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Changing Landscape of Alps: Europe

Why in News A recent study by the ETH technical university in Zurich, Switzerland shows that climate change has dramatically altered the Swiss Alp...

20 Jul 2021 Physical Geography
Heat Waves and Heat Dome

Why in News The Pacific North-west, known for its moderate climate, is experiencing a “historic” heat wave. The heat wave is being...

20 Jul 2021 Physical Geography
Moon’s Wobble Effect

Why in News Recently, the National Aeronautics and Space Administration (NASA) has highlighted Moon’s Wobble as a potential problem in the...

19 Jul 2021 Physical Geography
Discrete Auroras of Mars

Why in News Recently, the UAE’s Hope spacecraft has captured images of glowing atmospheric lights in the Mars night sky, known as discrete...

06 Jul 2021 Physical Geography
Heat Dome

Why in News Recently, the Pacific Northwest and some parts of Canada recorded temperatures around 47 degrees, causing a "historic" heat...

02 Jul 2021 Physical Geography
Exercise Sea Breeze

Why in News Ukraine and the United States launched joint naval Exercise ‘Sea Breeze’ in the Black Sea in a show of Western cooperation...

29 Jun 2021 Physical Geography
Black Sea

Why in News In a recent event, Russia alleged that the British warship had breached its territorial waters in Black Sea which Britain and most of...

25 Jun 2021 Physical Geography
Summer Solstice: 21st June

Why in News 21st June is the longest day in the Northern Hemisphere, technically this day is referred to as Summer solstice. In Delhi, the day...

21 Jun 2021 Physical Geography
Black Carbon and Glacier Melting

Why in News The report titled “Glaciers of the Himalayas: Climate Change, Black Carbon and Regional Resilience” says that the glaciers...

05 Jun 2021 Physical Geography
A-76: World’s Largest Iceberg

Why in News An enormous iceberg 'A-76' has calved from the western side of the Ronne Ice Shelf, lying in the Weddell Sea, in Antarctica. It...

21 May 2021 Physical Geography
Indian Monsoon Resembled Australian Monsoon

Why in News According to a recent study based on fossil leaves, Indian monsoon 25 million years ago resembled present day...

07 May 2021 Physical Geography
Climate Change Causing Shift in Earth’s Axis

Why in News A study published in Geophysical Research Letters of the American Geophysical Union (AGU) says that due to the significant melting of...

03 May 2021 Physical Geography
Assam Earthquake

Why in News Recently, a powerful earthquake measuring 6.4 on the Richter Scale jolted Assam and other parts of Northeast. According to the...

29 Apr 2021 Physical Geography
Types of Forests in India

Introduction Definition of Forest: At present, in India, there is no clear nationally-accepted definition of ‘forest’. States are...

26 Apr 2021 Physical Geography
Sulphur Dioxide Emissions from Caribbean Volcano

Why in News The Sulphur Dioxide (SO2) emissions from a volcanic eruption in the Caribbean (La Soufriere Volcano) have reached India, sparking fear...

20 Apr 2021 Physical Geography
Red Sea

Why in News An Iranian freighter was hit by Israel in the Red Sea in retaliation for past Iranian strikes on its vessels. The blast struck the...

08 Apr 2021 Physical Geography
Sangay Volcano: Ecuador

Why in News Recently, Ecuador’s Sangay volcano erupted. Key Points About Sangay Volcano: Sangay volcano is one of the highest active...

13 Mar 2021 Physical Geography
Declining Rainfall in Cherrapunji

Why in News A recent study that looked at the rainfall pattern in the past 119 years found a decreasing trend at Cherrapunji (Meghalaya) and nearby...

22 Feb 2021 Physical Geography
Deglaciation and Threats

Deglaciation Glaciers, ice caps and continental ice sheets cover some 10% of the earth’s land surface at the present time, whereas during...

22 Feb 2021 Physical Geography
Glaciers

About A glacier is a large, perennial accumulation of crystalline ice, snow, rock, sediment, and water that originates on land and moves down...

15 Feb 2021 Physical Geography

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		'article_id' => (int) 8914,
		'category_id' => (int) 21,
		'title' => 'Changing Landscape of Alps: Europe',
		'description' => '<h3>Why in News</h3>
<p>A recent study by the <strong>ETH technical university in Zurich, Switzerland</strong> shows that <a href="/daily-updates/daily-news-editorials/climate-change-and-development-in-india" target="_blank" rel="noopener"><strong>climate change</strong></a> has dramatically altered the <strong>Swiss Alp landscape.</strong></p>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>Important Findings:</strong><br />
<ul style="list-style-type: circle;">
<li>Melting<a href="/to-the-points/paper1/glaciers-6" target="_blank" rel="noopener"><strong> glaciers</strong></a> have <strong>created more than 1,000 new lakes</strong> across the mountains. <br />
<ul style="list-style-type: disc;">
<li>The inventory of Swiss Glacial lakes showed that almost <strong>1,200 new lakes have formed in formerly glaciated regions of the Swiss Alps</strong> since the end of the Little Ice Age around 1850 and around<strong> 1,000 of them still exist today.</strong></li>
</ul>
</li>
<li>Glaciers in the <strong>Swiss Alps are in steady decline,</strong> losing a full 2% of their volume last year alone.</li>
<li>Even if the world were to fully implement the <a href="/daily-updates/daily-news-analysis/five-years-of-paris-climate-accord" target="_blank" rel="noopener"><strong>2015 Paris Agreement</strong></a>, two-thirds of the Alpine glaciers will likely be lost.<br />
<ul style="list-style-type: disc;">
<li>The Paris Agreement is a legally binding international treaty on climate change. It was adopted by 196 Parties at COP 21 in Paris, in December 2015.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Alps:</strong><br />
<ul style="list-style-type: circle;">
<li><strong>About:<a href="http://www.drishtiias.com/images/uploads/1626765760_image3.png" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1626765760_image3.png" style="float: right;" width="350" caption="false" /></a></strong><br />
<ul style="list-style-type: disc;">
<li>The Alps <strong>emerged during the Alpine orogeny</strong> (mountain-building event), an event that began about <strong>65 million years</strong> ago as the <a href="/daily-updates/daily-news-analysis/monkeydactyl-pterosaur-species" target="_blank" rel="noopener"><strong>Mesozoic Era</strong></a> was drawing to a close.</li>
<li>Alps are <strong>young fold mountains</strong> with rugged relief and high conical peaks.</li>
<li>They are the<strong> most prominent of western Europe&rsquo;s physiographic regions.</strong> Some <strong>750 miles long</strong> and more than <strong>125 miles wide</strong> at their broadest point between Garmisch-Partenkirchen, Germany, and Verona, Italy, the<strong> Alps cover more than 80,000 square miles.</strong></li>
<li>The Alps extend north <strong>from the subtropical Mediterranean coast</strong> near Nice, France, <strong>to Lake Geneva before trending east-northeast to Vienna,</strong> Austria. There they touch the <a href="/daily-updates/daily-news-analysis/danube-sturgeon#:~:text=Danube%20is%20the%20second%20longest,mouth%20on%20the%20Black%20Sea." target="_blank" rel="noopener"><strong>Danube River</strong></a> and meld with the adjacent plain.</li>
<li>Because of their <strong>arclike shape,</strong> the Alps <strong>separate the marine west-coast climates</strong> of Europe<strong> from the Mediterranean areas</strong> of France, Italy, and the <a href="/daily-updates/daily-news-analysis/lithuania-quits-china-s-17-1" target="_blank" rel="noopener"><strong>Balkan region.</strong></a></li>
</ul>
</li>
<li><strong>Countries Covered:</strong><br />
<ul style="list-style-type: disc;">
<li>The Alps form part of<strong> France, Italy, Switzerland, Germany, Austria, Slovenia, Croatia, Bosnia and Herzegovina, Montenegro, Serbia, and Albania.</strong></li>
<li>Only<strong> Switzerland and Austria</strong> can be considered<strong> true Alpine countries.</strong></li>
</ul>
</li>
<li><strong>Important Peaks:</strong><br />
<ul style="list-style-type: disc;">
<li><strong>Mont Blanc</strong> is the highest peak in the Alps and in Europe, reaching a lofty 4,804 meters above sea level. It is located in the Graian Alps and lies within France, Switzerland, and Italy.</li>
<li><strong>Monte Rosa</strong> is a massif (a compact group of mountains) consisting of several peaks. The highest peak in this range<strong> (Dufourspitze)</strong> has an elevation of 4,634 meters, claiming the title of <strong>Switzerland&rsquo;s highest peak.</strong></li>
<li><strong>Dom,</strong> which is located near Monte Rosa, Dom stands at<strong> 4,545 meters</strong> and is known as one of the &ldquo;easier&rdquo; tall peaks in the Alps to summit because of it&rsquo;s<strong> straightforward routes.</strong></li>
<li>Other major peaks are Liskamm, Weisshorn, Matterhorn, Dent Blanche, Grand Combin etc.</li>
</ul>
</li>
</ul>
</li>
</ul>
<h3>Major Mountain Ranges of the World</h3>
<p><a href="http://www.drishtiias.com/images/uploads/1626765724_image1.png" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1626765724_image1.png" style="display: block; margin-left: auto; margin-right: auto;" width="750" caption="false" /></a></p>
<p><a href="https://www.thehindu.com/news/international/climate-change-has-added-over-1000-lakes-in-swiss-alps-study/article35413498.ece#:~:text=Share%20Article-,Glaciers%20there%20lost%20a%20full%202%25%20of%20their%20volume%20last,study%20published%20on%20Monday%20showed." target="_blank" rel="noopener"><strong>Source: TH</strong></a></p>',
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		'article_id' => (int) 8912,
		'category_id' => (int) 26,
		'title' => 'Heat Waves and Heat Dome',
		'description' => '<h3>Why in News</h3>
<ul style="list-style-type: square;">
<li>The Pacific North-west, known for its moderate climate, is experiencing a<strong> &ldquo;historic&rdquo;</strong> heat wave. The heat wave is being described as a &ldquo;<a href="/daily-updates/daily-news-analysis/heat-dome" target="_blank" rel="noopener"><strong>Heat Dome</strong></a>&rdquo;. <br />
<ul style="list-style-type: circle;">
<li>It has stretched emergency services, with at least 134 people dying suddenly since the last few days in parts of Canada.</li>
</ul>
</li>
</ul>
<h3>Heat Waves and Heat Dome</h3>
<ul style="list-style-type: square;">
<li><strong>Heat Wave:</strong> <br />
<ul style="list-style-type: circle;">
<li>A heat wave is a period of abnormally high temperatures, more than the normal maximum temperature that lasts for more than two days.</li>
<li>Heat waves can occur with or without high humidity and have the potential to cover a large area, exposing a high number of people to <strong>hazardous heat.</strong></li>
<li><strong>Increasing Trend of Heat Waves:</strong><br />
<ul style="list-style-type: disc;">
<li>In the past few decades, heat waves have become larger, <strong>affecting 25% more land area in the <a href="/daily-updates/daily-news-analysis/autumnal-equinox-in-northern-hemisphere" target="_blank" rel="noopener">Northern Hemisphere</a></strong> than they did in 1980. </li>
<li>Including the <strong>ocean areas, heat waves have grown by 50%.</strong></li>
</ul>
</li>
</ul>
</li>
<li><strong>Heat Dome:</strong> <br />
<ul style="list-style-type: circle;">
<li>A heat dome occurs when the atmosphere traps hot ocean air like a lid or cap.</li>
<li>As per <strong>National Oceanic and Atmospheric Administration (NOAA), USA,</strong> a heat dome is created when strong high-pressure atmospheric conditions combine with weather patterns like <strong><a href="/to-the-points/paper1/el-nino-and-la-nina" target="_blank" rel="noopener">La Ni&ntilde;a</a>.</strong> </li>
<li>They are <strong>more likely to form during La Ni&ntilde;a years</strong> like 2021, when waters are cool in the eastern Pacific and warm in the western Pacific. creating vast areas of sweltering. </li>
<li><strong>Duration of Heat Domes:</strong> <br />
<ul style="list-style-type: disc;">
<li>According to NOAA, a heat dome typically lasts<strong> a week.</strong> </li>
<li>The formation after a week becomes too bog to keep standing and falls over, releasing the trapped air and ending the swelter. </li>
</ul>
</li>
</ul>
</li>
<li><strong>Causes of Formation of Heat Dome: </strong><br />
<ul style="list-style-type: circle;">
<li><strong>Change in Ocean Temperature:</strong> The phenomenon begins when there is a <strong>strong change (or gradient) in ocean temperatures.</strong> <br />
<ul style="list-style-type: disc;">
<li>In the process known as <strong>convection,</strong> the gradient causes more warm air, heated by the ocean surface, to rise over the ocean surface.</li>
<li>As prevailing winds move the hot air east, the northern shifts of the jet stream trap the air and move it toward land, where it sinks, <strong>resulting in heat waves.</strong></li>
</ul>
</li>
<li><strong>Change in Atmospheric Pressure:</strong> Heat waves begin when <strong>high pressure in the atmosphere moves in and pushes warm air</strong> toward the ground. This effect is fuelled by heat rising from the ocean, creating an amplification loop.<br />
<ul style="list-style-type: disc;">
<li>The high-pressure system pressing down on the ground expands vertically, forcing other weather systems to change course. <br />
<ul style="list-style-type: disc;">
<li>It even minimizes wind and cloud cover, making the air more stifling. </li>
<li>This is also why a heat wave parks itself over an area for several days or longer.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Climate Change:</strong> The rising temperatures lead to hotter weather. Heat waves have been a regular phenomenon on land. <br />
<ul style="list-style-type: disc;">
<li>However, <strong>global warming has caused them to be hotter with a longer duration</strong> and an increased frequency.</li>
<li>Scientists studying the climate tend to agree that the heat waves occurring today are more likely to be a result of climate change for which humans are responsible.</li>
</ul>
</li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1626762592_image1.jpg" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1626762592_image1.jpg" style="display: block; margin-left: auto; margin-right: auto;" width="700" caption="false" /></a></p>
<ul style="list-style-type: square;">
<li><strong>Impact of Heat Waves and Heat Domes:</strong><br />
<ul style="list-style-type: circle;">
<li><strong>Risk of Wildfires:</strong> The heat domes act as fuel to <strong><a href="/daily-updates/daily-news-analysis/forest-fires-a-very-big-concern" target="_blank" rel="noopener">wildfires</a></strong>, which destroys a lot of land area every year in countries like the US.</li>
<li><strong>Prevents Cloud Formation:</strong> The condition also <strong>prevents clouds from forming,</strong> allowing for more radiation from the sun to hit the ground. </li>
<li><strong>Heat Strokes and Sudden Fatalities:</strong> The very high temperatures or humid conditions pose an elevated risk of <a href="/daily-updates/daily-news-analysis/heat-waves" target="_blank" rel="noopener"><strong>heatstroke</strong></a> or<strong> heat exhaustion.</strong><br />
<ul style="list-style-type: disc;">
<li><strong>Older people and people with chronic illness</strong> such as <a href="/daily-updates/daily-news-analysis/higher-mortality-from-cardio-vascular-diseases" target="_blank" rel="noopener"><strong>heart disease</strong></a>, <a href="/daily-updates/daily-news-analysis/acute-respiratory-infections" target="_blank" rel="noopener"><strong>respiratory disease</strong></a>, and <a href="/daily-updates/daily-news-analysis/world-diabetes-day-2019#:~:text=The%20World%20Health%20Organisation%20(WHO,is%20%E2%80%9CFamily%20and%20Diabetes%E2%80%9D." target="_blank" rel="noopener"><strong>diabetes</strong></a> are <strong>more susceptible to heatstroke,</strong> as the body&rsquo;s ability to regulate heat deteriorates with age.</li>
<li>Houses without air conditioners experience an unbearable rise in temperature of their home which can lead to<strong> sudden deaths.</strong></li>
</ul>
</li>
<li><strong>Effect on Vegetation:</strong> The trapping of heat can also <strong>damage crops, dry out vegetation</strong> and result in <a href="/daily-updates/daily-news-analysis/el-ni%C3%B1o-drought" target="_blank" rel="noopener"><strong>droughts.</strong></a></li>
<li><strong>Increased Energy Demands:</strong> The sweltering heat wave also leads to rise in energy demand, especially electricity, leading to pushing up rates.</li>
<li><strong>Power Related Issues:</strong> Heat waves are often high mortality disasters.<br />
<ul style="list-style-type: disc;">
<li>Avoiding heat-related disasters depends on the resilience of the electrical grid, which can fail if electricity demand due to air conditioning use exceeds supply.</li>
<li>As a result, there is the <strong>double risk of infrastructure failure and health impacts.</strong></li>
</ul>
</li>
</ul>
</li>
</ul>
<h3>Steps for Avoiding Heat Waves</h3>
<ul style="list-style-type: square;">
<li><strong>Individual Level: </strong><br />
<ul style="list-style-type: circle;">
<li><strong>Staying Hydrated:</strong> Staying indoor and at rest in a very dry room with about 10% relative humidity, and drinking water constantly (for producing sweat), can help avoid overheating at temperatures as high as 46℃.<br />
<ul style="list-style-type: disc;">
<li>However, there is a limit to this, called the<strong> wet-bulb temperature,</strong> which considers heat and humidity, beyond which humans cannot tolerate high temperatures.</li>
</ul>
</li>
<li><strong>Altering Workout Routines:</strong> Exercising early in the morning when it is still cool or in air conditioned indoor spaces. <br />
<ul style="list-style-type: disc;">
<li>Skipping workout routines can also be considered given the extreme heat. </li>
</ul>
</li>
</ul>
</li>
<li><strong>Public Level: </strong><br />
<ul style="list-style-type: circle;">
<li><strong>Public Cooling Shelters:</strong> A number of emergency cooling shelters can be opened so that people without domestic air conditioning units can escape the heat.<br />
<ul style="list-style-type: disc;">
<li>Air-conditioned rooms and buildings are the biggest help to people caught under a heat dome.</li>
</ul>
</li>
<li><strong>Portable ACs:</strong> Portable air-conditioning units, along with fans and even ice are also useful. </li>
</ul>
</li>
<li><strong>Long Term Solutions: </strong><br />
<ul style="list-style-type: circle;">
<li><strong>Afforestation:</strong> Trees don&rsquo;t just provide much-needed shade for a sweaty city. The water evaporating from their leaves can cool a neighborhood by a few degrees during the hottest periods.<br />
<ul style="list-style-type: disc;">
<li>Tree leaves also absorb and filter local air pollution; heat waves can worsen urban smog, which may put comorbids at risk.</li>
</ul>
</li>
<li><strong>Replacing Dark Roofs:</strong> A big reason that cities are so much hotter than rural areas is that they are covered by dark roofs, roads and parking lots that absorb and retain heat. <br />
<ul style="list-style-type: disc;">
<li>Replacing the dark surfaces with lighter more reflective materials will result in a comparatively cooler environment.</li>
</ul>
</li>
<li><strong>Preparing for the Blackout:</strong> A widespread blackout during a heat wave can leave millions of people without electricity for fans or air-conditioners. <br />
<ul style="list-style-type: disc;">
<li>Smarter grids and new forecasting tools could help electric utilities prepare for heat waves. </li>
<li>Using electronic controls to pre-cool buildings before temperatures peak in the daytime.</li>
</ul>
</li>
</ul>
</li>
</ul>',
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		'article_id' => (int) 8909,
		'category_id' => (int) 21,
		'title' => 'Moon’s Wobble Effect',
		'description' => '<h3>Why in News</h3>
<p>Recently, the <a href="/important-institutions/drishti-specials-important-institutions-international-institution/national-aeronautics-and-space-administration-nasa" target="_blank" rel="noopener"><strong>National Aeronautics and Space Administration</strong></a> (NASA) has highlighted<strong> Moon&rsquo;s Wobble</strong> as a<strong> potential problem in the near future.</strong></p>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>Moon&rsquo;s Wobble:</strong><br />
<ul style="list-style-type: circle;">
<li>When the Moon makes its <strong>elliptical orbit,</strong> its<strong> velocity varies and alters causing our perspective of the "light side"</strong> to appear at <strong>slightly different angles.</strong> This is what it calls the Moon&rsquo;s wobble or that is how it appears to our eyes.</li>
<li>It is a <strong>cyclical shift in the moon&rsquo;s orbit,</strong> it is a <strong>regular swaying (Oscillation) in the moon&rsquo;s orbit.</strong></li>
<li>It was first documented <strong>way back in 1728.</strong> This wobble takes<strong> over an 18.6-year</strong> period to complete. It acts as a background of <a href="/daily-updates/daily-news-analysis/rising-sea-levels" target="_blank" rel="noopener"><strong>sea level rise.</strong></a></li>
</ul>
</li>
<li><strong>Impact of Wobble on Earth:</strong><br />
<ul style="list-style-type: circle;">
<li>The moon wobble impacts the gravitational pull of the moon, and therefore, indirectly influences <strong>the ebb and flow of tides</strong> on the Earth.</li>
<li>Each wobble cycle has the <strong>power to amplify and suppress the tides on Earth.</strong><br />
<ul style="list-style-type: disc;">
<li>During<strong> half of the Moon&rsquo;s orbit of 18.6 years, the Earth's regular tides are suppressed</strong> i.e. high tides are lower than normal and low tides higher than normal (Current situation).</li>
<li>In the <strong>other half, the effect is reversed, which is called the tide-amplifying phase</strong> of the Moon.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Related Concerns:</strong><br />
<ul style="list-style-type: circle;">
<li>The<strong> lunar cycle is expected to shift again by mid-2030,</strong> and in the coming phase, the <strong>tides will amplify once again.</strong></li>
<li>The upcoming changes in the lunar cycle will pose a serious threat, as the amplified <strong>high tides coupled with the rising sea levels</strong> will make the risk of flooding far greater across<strong> all coastal regions of the globe.</strong><br />
<ul style="list-style-type: disc;">
<li>It raises<strong> the baseline,</strong> and the more the baseline is raised, the smaller the weather event to cause flooding.</li>
</ul>
</li>
<li>The <strong>high tide-associated <a href="/daily-updates/daily-news-editorials/flood-management-in-india" target="_blank" rel="noopener">floods</a></strong>&mdash;also known as nuisance floods or sunny day floods&mdash;<strong>may occur in clusters that could last for months</strong> or even for longer periods.</li>
<li>This surge will be closely associated with the <strong>position of the Moon, Earth and the Sun. </strong></li>
</ul>
</li>
</ul>
<div class="border-bg">
<p><strong>Tides</strong></p>
<ul style="list-style-type: square;">
<li><strong>About:<a href="http://www.drishtiias.com/images/uploads/1626691979_image3.png" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1626691979_image3.png" style="float: right;" width="350" caption="false" /></a></strong><br />
<ul style="list-style-type: circle;">
<li>Tides can be defined as the <strong>alternate rise and fall of the ocean water. </strong></li>
</ul>
</li>
<li><strong>Occurrence:</strong><br />
<ul style="list-style-type: circle;">
<li>It is caused by the combined effects of the <strong>gravitational force</strong> exerted on Earth<strong> by the Sun,</strong> the gravitational force exerted on Earth <strong>by the Moon and rotation of the Earth.</strong></li>
</ul>
</li>
<li><strong>Types:</strong> <br />
<ul style="list-style-type: circle;">
<li><strong>Spring Tide:</strong> It occurs during the<strong> full moon and new moon days</strong> when the sun, the moon and the earth are in the same line twice each lunar month all year long, without regard to the season.</li>
<li><strong>Neap Tide:</strong> It occurs when the moon is in<strong> its first and last quarter,</strong> the ocean waters get drawn<strong> in diagonally opposite directions</strong> by the gravitational pull of sun and earth resulting in low tides.</li>
</ul>
</li>
<li><strong>Stages of Tidal Changes:<a href="http://www.drishtiias.com/images/uploads/1626691998_image5.png" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1626691998_image5.png" style="float: right;" width="350" caption="false" /></a></strong><br />
<ul style="list-style-type: circle;">
<li><strong>High tide</strong> is the stage when the tidal crest arrives at a particular location on shore, raising the local sea level.</li>
<li><strong>Low tide</strong> is the stage when the trough arrives, lowering the local sea level.</li>
<li><strong>Flood tide</strong> is a rising or incoming tide between low tide and high tide.</li>
<li><strong>Ebb tide</strong> is a falling or outgoing tide between high tide and low tide. <br />
<ul style="list-style-type: disc;">
<li>The vertical distance between high tide and low tide is the tidal range.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Impact:</strong><br />
<ul style="list-style-type: circle;">
<li>Tides affect other aspects of <strong>oceanic life, including the reproductive activities</strong> of fish and ocean plants.</li>
<li>High tides <strong>help in navigation.</strong> They raise the water level close to the shores which helps the <strong>ships to arrive at the harbour more easily.</strong></li>
<li>Tides stirr the ocean water that<strong> makes habitable climatic conditions</strong> and balance the temperatures on the planets.</li>
<li>The fast movement of water<strong> during the inflow and outflow</strong> will provide a source of renewable energy to communities living along the coast.</li>
</ul>
</li>
</ul>
</div>
<p><a href="https://indianexpress.com/article/explained/explained-how-the-moon-wobble-affects-rising-tides-7410814/" target="_blank" rel="noopener"><strong>Source: IE</strong></a></p>',
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	(int) 3 => object(Cake\ORM\Entity) {

		'article_id' => (int) 8789,
		'category_id' => (int) 21,
		'title' => 'Discrete Auroras of Mars',
		'description' => '<h3>Why in News</h3>
<p>Recently, the <strong>UAE&rsquo;s <a href="/daily-updates/daily-news-analysis/uae-s-hope-mars-mission" target="_blank" rel="noopener">Hope spacecraft</a></strong> has captured <strong>images of glowing atmospheric lights in the Mars night sky, known as discrete auroras.</strong></p>
<ul style="list-style-type: square;">
<li>The Hope Probe, the Arab world&rsquo;s first mission to Mars, took off from Earth in July 2020, and has been orbiting the Red Planet (Mars) since February 2021. It is expected to create the <strong>first complete portrait of the planet&rsquo;s atmosphere.</strong></li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1625558022_image.png" target="_blank" rel="noopener"><strong><img class="content-img" src="http://www.drishtiias.com/images/uploads/1625558022_image.png" style="display: block; margin-left: auto; margin-right: auto;" width="400" caption="false" /></strong></a></p>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>Auroras:</strong><br />
<ul style="list-style-type: circle;">
<li>An Aurora is <strong>a display of light in the sky predominantly seen in the high latitude regions</strong> (Arctic and Antarctic). It is <strong>also known as a Polar light.</strong></li>
<li>They commonly occur at high northern and southern latitudes, less frequent at mid-latitudes, and seldom seen near the equator.</li>
<li>While <strong>usually a milky greenish color</strong>, auroras can also show red, blue, violet, pink, and white. These colors appear in a variety of continuously changing shapes.</li>
<li>Auroras are <strong>not just something that happens on Earth.</strong> If a planet has an atmosphere and magnetic field, they probably have auroras.</li>
</ul>
</li>
<li><strong>Cause of Auroras on Earth:</strong><br />
<ul style="list-style-type: circle;">
<li>Auroras are caused <strong>when charged particles ejected from the Sun&rsquo;s surface - called the solar wind - enter the Earth&rsquo;s atmosphere.</strong></li>
<li>The typical aurora is <strong>caused by collisions between charged particles from space with the oxygen and nitrogen in Earth&rsquo;s upper atmosphere.</strong></li>
<li>The electrons - which come from the<a href="/daily-updates/daily-news-analysis/1-d-simulation-code-to-study-earth-s-magnetosphere" target="_blank" rel="noopener"><strong> Earth&rsquo;s magnetosphere</strong></a>, the region of space controlled by Earth&rsquo;s magnetic field - transfer their energy to the oxygen and nitrogen atoms and molecules, making them &ldquo;excited&rdquo;.</li>
<li>When a large number of electrons come from the magnetosphere to bombard the atmosphere, the<strong> oxygen and nitrogen can emit enough light for the eye to detect, giving us beautiful auroral displays.</strong></li>
<li>In the <strong>northern part of our globe, </strong>the<strong> polar lights are called aurora borealis or Northern Lights</strong>, and are seen from the US (Alaska), Canada, Iceland, Greenland, Norway, Sweden and Finland.</li>
<li>In the <strong>south, they are called aurora australis or southern lights</strong>, and are visible from high latitudes in Antarctica, Chile, Argentina, New Zealand and Australia.</li>
</ul>
</li>
<li><strong>Discrete Auroras of Mars:</strong><br />
<ul style="list-style-type: circle;">
<li>Unlike auroras on Earth, which are seen only near the north and south poles, <strong>Discrete Auroras (DA) on Mars are seen all around</strong> the planet at night time.</li>
<li>These DAs are traced out where <strong>energetic particles excite the atmosphere</strong> after being funneled down by a patchy network of crustal <strong>magnetic fields that originate from minerals</strong> on the surface of Mars.</li>
</ul>
</li>
<li><strong>Martian Auroras are Different:</strong><br />
<ul style="list-style-type: circle;">
<li>Unlike Earth, which has a strong magnetic field, the <strong>Martian magnetic field has largely died out.</strong> This is because the molten iron at the interior of the planet - which produces magnetism - has cooled.</li>
<li>However, the <strong>Martian crust</strong>, which hardened billions of years ago when the magnetic field still existed, <strong>retains some magnetism.</strong></li>
<li>So, in contrast with Earth, which acts like one single bar magnet, <strong>magnetism on Mars is unevenly distributed</strong>, with fields strewn across the planet and differing in direction and strength.</li>
<li>These <strong>disjointed fields channel the solar wind to different parts of the Martian atmosphere</strong>, creating &ldquo;discrete&rdquo; auroras over the entire surface of the planet as charged particles interact with atoms and molecules in the sky&ndash; as they do on Earth.</li>
</ul>
</li>
<li><strong>Significance:</strong><br />
<ul style="list-style-type: circle;">
<li>Studying Martian auroras is important for scientists, for it <strong>can offer clues as to why the Red Planet lost its magnetic field and thick atmosphere</strong>&ndash; among the essential requirements for sustaining life.</li>
<li>With the information gathered during the UAE&rsquo;s Mars mission, scientists will have<strong> a better understanding of the climate dynamics of different layers of Mars&rsquo; atmosphere.</strong></li>
</ul>
</li>
</ul>
<div class="border-bg">
<p><strong>Other Mars Missions</strong></p>
<ul style="list-style-type: square;">
<li><a href="/daily-updates/daily-news-analysis/nasa-s-mars-2020-mission" target="_blank" rel="noopener"><strong>NASA's Mars 2020 Mission</strong></a> <strong>(Perseverance Rover)</strong>: The mission is designed to better understand the geology of Mars and seek signs of ancient life.</li>
<li><strong><a href="/daily-updates/daily-news-analysis/tianwen-1-china-s-mars-mission-1" target="_blank" rel="noopener">Tianwen-1: China's Mars Mission</a>:</strong> It was launched in 2019 to conduct scientific investigations into the planet&rsquo;s soil, geological structure, environment, atmosphere and water.</li>
<li><strong>India&rsquo;s <a href="/important-institutions/drishti-specials-important-institutions-national-institutions/indian-space-research-organisation-isro" target="_blank" rel="noopener">Mars Orbiter Mission (MOM)</a> or Mangalyaan:</strong> It was launched from the Satish Dhawan Space Centre in Andhra Pradesh by Indian Space Research Organisation in November 2013.</li>
</ul>
</div>
<p><a href="https://indianexpress.com/article/explained/uae-hope-orbiter-discrete-auroras-mars-7390298/" target="_blank" rel="noopener"><strong>Source: IE</strong></a></p>',
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		'article_id' => (int) 8761,
		'category_id' => (int) 21,
		'title' => 'Heat Dome',
		'description' => '<h3>Why in News</h3>
<p>Recently, the Pacific Northwest and some parts of Canada recorded temperatures around 47 degrees, causing a "historic" heat wave.</p>
<ul style="list-style-type: square;">
<li>This is a result of a phenomenon referred to as a <strong>"heat dome".</strong></li>
</ul>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>About:</strong><br />
<ul style="list-style-type: circle;">
<li>The phenomenon begins when there is<strong> a strong change (or gradient) in ocean temperatures.</strong> In the process<strong> known as convection,</strong> the gradient causes more warm air, heated by the ocean surface, to rise over the ocean surface.</li>
<li>As prevailing <strong>winds move the hot air east,</strong> the <strong>northern shifts of the jet stream trap the air</strong> and move it toward land, where it sinks, resulting in heat waves.<br />
<ul style="list-style-type: disc;">
<li><strong>Jet streams are relatively narrow bands of strong wind</strong> in the upper levels of the atmosphere. The winds blow <strong>from west to east in jet streams</strong> but the flow often<strong> shifts to the north and south.</strong></li>
</ul>
</li>
<li>This <strong>strong change in ocean temperature from the west to the east</strong> is the reason for the<strong> heat dome (HD).</strong><br />
<ul style="list-style-type: disc;">
<li>The<strong> western Pacific ocean&rsquo;s temperatures</strong> have increased in the past few decades and are<strong> relatively more than the temperature in the eastern Pacific.</strong></li>
</ul>
</li>
<li>HD also prevents clouds from forming, allowing for more radiation from the sun to hit the ground.</li>
<li>A heat dome is<strong> effectively what it sounds like</strong> - an area of high pressure that parks over a region like a lid on a pot, trapping heat. They are more likely to form during<a href="/to-the-points/paper1/el-nino-and-la-nina" target="_blank" rel="noopener"><strong> La Ni&ntilde;a</strong></a> years like 2021, when waters are cool in the eastern Pacific and warm in the western Pacific.</li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1625217033_image1.jpg" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1625217033_image1.jpg" style="display: block; margin-left: auto; margin-right: auto;" caption="false" width="628" height="454" /></a></p>
<ul style="list-style-type: square;">
<li><strong>Heat Wave:</strong><br />
<ul style="list-style-type: circle;">
<li>A heat wave is <strong>a period of abnormally high temperatures,</strong> more than the normal maximum temperature that lasts for more than two days.</li>
<li>Heat waves <strong>typically occur between March and June,</strong> and in some rare cases even extend till July.</li>
<li>Heat waves can occur with or without high humidity and have the potential to cover a large area,<strong> &ldquo;exposing a high number of people to hazardous heat.&rdquo;</strong></li>
</ul>
</li>
<li><strong>Impact on Humans (Wet-bulb temperature):</strong><br />
<ul style="list-style-type: circle;">
<li>As long as the body is producing sweat, which is then able to evaporate quickly, the <strong>body will be able to remain cool even under high temperatures.</strong></li>
<li>Wet-bulb temperature (WBT) is <strong>a limit that considers heat and humidity beyond which humans can not tolerate high temperatures.</strong></li>
<li>Temperatures beyond WBT<strong> can cause heat related illnesses including heat stroke, heat exhaustion, sunburn and heat rashes.</strong> Sometimes these can prove fatal.</li>
</ul>
</li>
<li><strong>Effects of Heat Dome:</strong><br />
<ul style="list-style-type: circle;">
<li>Those living without an air conditioner see the temperatures of their homes rising to unbearably high, leading to sudden fatalities.</li>
<li>The trapping of heat <strong>can also damage crops, dry out vegetation and result in droughts.</strong></li>
<li>The sweltering heat wave will also<strong> lead to rise in energy demand,</strong> especially electricity, leading to pushing up rates.</li>
<li>The heat domes <strong>can also act as fuel to wildfires,</strong> which destroys a lot of land area in the US every year.</li>
</ul>
</li>
<li><strong>Climate change and heat domes:</strong><br />
<ul style="list-style-type: circle;">
<li>The weather scientists have been highlighting the effects of climate change on more extreme heat waves.<br />
<ul style="list-style-type: disc;">
<li>According to a 2017 NOAA (National Oceanic and Atmospheric Administration) survey, average US temperatures have increased since the late 19<sup>th</sup> century.</li>
</ul>
</li>
<li>However, Scientists are usually wary of linking climate change to any contemporary event mainly because of the difficulty in completely ruling out the possibility of the event having been caused by some other reason, or being a result of natural variability.</li>
</ul>
</li>
</ul>
<p><a href="https://indianexpress.com/article/explained/what-is-the-heat-dome-causing-record-high-temperatures-in-parts-of-north-america-7384994/" target="_blank" rel="noopener"><strong>Source: IE</strong></a></p>',
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	(int) 5 => object(Cake\ORM\Entity) {

		'article_id' => (int) 8730,
		'category_id' => (int) 21,
		'title' => 'Exercise Sea Breeze',
		'description' => '<h3>Why in News</h3>
<p><strong>Ukraine and the United States</strong> launched<strong> joint naval Exercise &lsquo;Sea Breeze&rsquo; in the Black Sea</strong> in a show of Western cooperation with Ukraine as it faces off with Russia.</p>
<ul style="list-style-type: square;">
<li>The drills come just days after the <a href="/daily-updates/daily-news-analysis/black-sea" target="_blank" rel="noopener"><strong>British Royal Navy&rsquo;s HMS Defender passed near Russian-annexed Crimea</strong></a> in the Black Sea.</li>
</ul>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>About the Exercise:</strong><br />
<ul style="list-style-type: circle;">
<li>The exercise Sea Breeze <strong>has been held since 1997,</strong> involving <a href="/daily-updates/daily-news-analysis/nato-ally-status-to-india" target="_blank" rel="noopener"><strong>NATO states </strong></a>and<strong> their allies in the Black Sea region.</strong></li>
<li>It has taken place <strong>21 times since 1997.</strong> This edition (2021) will be the <strong>largest In Exercise&rsquo;s history</strong> that will involve some 5,000 military personnel from more than 30 countries.</li>
</ul>
</li>
<li><strong>Aim of the Exercise:</strong><br />
<ul style="list-style-type: circle;">
<li>The drill is<strong> aimed at improving naval and land operations</strong> and improving cooperation among participating counties.</li>
<li>The exercise is also aimed at sending a powerful message to <strong>maintain stability and peace in the region.</strong></li>
</ul>
</li>
<li><strong>Significance of Black Sea for Russia:</strong><br />
<ul style="list-style-type: circle;">
<li>The unique geography of the Black Sea region confers several <strong>geopolitical advantages to Russia</strong> and thus Russia always wanted to control the region. <br />
<ul style="list-style-type: disc;">
<li>Firstly, it is an <strong>important crossroads and strategic intersection</strong> for the entire region. Access to the Black Sea is<strong> vital for all littoral and neighboring states,</strong> and greatly enhances the projection of power into several adjacent regions.</li>
<li>Secondly, the region is an <strong>important transit corridor for goods and energy.</strong></li>
<li>Thirdly, the Black Sea region is<strong> rich in cultural and ethnic diversity,</strong> and due to geographical proximity, shares <strong>close historical ties with Russia.</strong></li>
</ul>
</li>
<li>Following such interest, <strong>Russia annexed Crimea from Ukraine in 2014</strong> and claims the waters around the peninsula as part of its territory. <br />
<ul style="list-style-type: disc;">
<li>Most countries do not recognise the takeover and stand behind Ukraine&rsquo;s claims to the waters.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Black Sea:</strong><br />
<ul style="list-style-type: circle;">
<li>This marginal sea of the Atlantic Ocean, located between Eastern Europe and Western Asia.</li>
<li>The bordering countries of Black Sea are:<strong> Russia, Ukraine, Georgia, Turkey, Bulgaria and Romania.</strong></li>
<li>The Black Sea <strong>happens to be the largest water body with a meromictic basin,</strong> which means the movement of water between the lower and upper layers of the sea is a rare phenomenon which is also responsible for its <strong>Anoxic Water</strong> (i.e. a significant absence of oxygen in the water).</li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1624962298_image4.png" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1624962298_image4.png" style="display: block; margin-left: auto; margin-right: auto;" caption="false" width="512" height="288" /></a></p>
<p><a href="https://www.thehindu.com/news/international/ukraine-us-launch-black-sea-drills/article35023668.ece" target="_blank" rel="noopener"><strong>Source: TH</strong></a></p>',
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	(int) 6 => object(Cake\ORM\Entity) {

		'article_id' => (int) 8695,
		'category_id' => (int) 21,
		'title' => 'Black Sea',
		'description' => '<h3>Why in News</h3>
<p>In a recent event, Russia alleged that the British warship had <strong>breached its territorial waters in Black Sea</strong> which Britain and most of the world say <strong>belong to Ukraine.</strong></p>
<ul style="list-style-type: square;">
<li>Russia seized and annexed the Crimea peninsula from Ukraine in 2014 and considers areas around its coast to be Russian waters.</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1624606295_pasted%20image 0 (2).png" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1624606295_pasted image 0 (2).png" style="display: block; margin-left: auto; margin-right: auto;" width="450" caption="false" /></a></p>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>Geographical Location of Black Sea:</strong><br />
<ul style="list-style-type: circle;">
<li>The Black Sea,<strong> also known as the Euxine Sea</strong>, is one of the major water bodies and <strong>a famous inland</strong> sea of the world.</li>
<li>This <strong>marginal sea of the Atlantic Ocean</strong>, located <strong>between Eastern Europe and Western Asia.</strong></li>
<li>It is surrounded by the <strong>Pontic, Caucasus, and Crimean Mountains</strong> in the south, east and north respectively.</li>
<li>The Turkish straits system - the <strong>Dardanelles, Bosporus and Marmara Sea</strong> - forms a transitional zone between the <strong>Mediterranean</strong> and the Black Sea.</li>
<li>The Black Sea is also connected to the <strong>Sea of Azov</strong> by the <strong>Strait of Kerch.</strong></li>
<li>The <strong>bordering countries</strong> of Black Sea are: <strong>Russia, Ukraine, Georgia, Turkey, Bulgaria and Romania.</strong></li>
</ul>
</li>
<li><strong>Anoxic Water:</strong><br />
<ul style="list-style-type: circle;">
<li>There is a <strong>significant absence of oxygen in the water.</strong></li>
<li>The Black Sea happens to be the largest water body with a <strong>meromictic basin</strong>, which means the <strong>movement of water between the lower and upper layers of the sea is a rare phenomenon</strong> to find anywhere in the world.</li>
<li>The anoxic condition is also caused due to the presence of the process of <a href="/to-the-points/paper3/marine-pollution#:~:text=Eutrophication%3A%20When%20a%20water%20body,depletion%20of%20the%20water%20body." target="_blank" rel="noopener"><strong>Eutrophication</strong> </a>in the sea.</li>
</ul>
</li>
</ul>
<div class="border-bg">
<p><strong>Anoxic Waters</strong></p>
<ul style="list-style-type: square;">
<li>Anoxic waters are areas of sea water, fresh water, or groundwater that are <strong>depleted of dissolved oxygen</strong> and are a more severe condition of hypoxia.</li>
<li>This condition is <strong>generally found in areas that have restricted water exchange.</strong></li>
</ul>
</div>
<ul style="list-style-type: square;">
<li><strong>International Rules of Passage through Sea:</strong><br />
<ul style="list-style-type: circle;">
<li>Under international law of the sea <a href="/daily-updates/daily-news-analysis/unclos-maritime-zones" target="_blank" rel="noopener"><strong>(United Nations Convention on the Law of the Sea (UNCLOS) 1982)</strong></a>, <strong>innocent passage permits a vessel to pass</strong> through another state&rsquo;s territorial waters so long as this does not affect its security.</li>
</ul>
</li>
</ul>
<p><a href="https://www.thehindu.com/news/international/russia-uk-spar-over-black-sea-incident/article34955128.ece" target="_blank" rel="noopener"><strong>Source:TH</strong></a></p>',
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	(int) 7 => object(Cake\ORM\Entity) {

		'article_id' => (int) 8658,
		'category_id' => (int) 21,
		'title' => 'Summer Solstice: 21st June',
		'description' => '<h3>Why in News</h3>
<p>21<sup>st</sup> June is the <strong>longest day</strong> in the Northern Hemisphere, technically this day is referred to as <strong>Summer solstice.</strong> In <strong>Delhi, the day length</strong> is around <strong>14 hours.</strong></p>
<ul style="list-style-type: square;">
<li>The amount of light received by <strong>a specific area</strong> in the <strong>Northern Hemisphere</strong> during the summer solstice depends on the<strong> latitudinal location</strong> of the place.</li>
<li>21<sup>st</sup> June is also observed as the <a href="/daily-updates/daily-news-analysis/international-day-of-yoga" target="_blank" rel="noopener"><strong>International Yoga Day.</strong></a></li>
</ul>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>Meaning of the Word &lsquo;Solstice&rsquo;:</strong><br />
<ul style="list-style-type: circle;">
<li>It is a Latin word that means <strong>&lsquo;stalled sun&rsquo;.</strong> It is a natural phenomenon that<strong> occurs twice every year,</strong> once in the summer and again during winter, in <strong>each hemisphere of the earth - Summer and <a href="/daily-updates/daily-news-analysis/winter-solstice#:~:text=21st%20December%20or%20the,day%2C%20in%20the%20Southern%20Hemisphere." target="_blank" rel="noopener">Winter Solstice</a>.</strong></li>
</ul>
</li>
<li><strong>About Summer Solstice:<a href="http://www.drishtiias.com/images/uploads/1624276808_image3.png" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1624276808_image3.png" style="display: block; margin-left: auto; margin-right: auto;" width="500" caption="false" /></a></strong><br />
<ul style="list-style-type: circle;">
<li>It is the<strong> longest day and shortest night</strong> of the year in the <strong>Northern Hemisphere.</strong></li>
<li>During this, <strong>countries in the Northern Hemisphere are nearest to the Sun </strong>and the <strong>Sun shines overhead on the Tropic of Cancer (23.5&deg; North).</strong><br />
<ul style="list-style-type: disc;">
<li>At latitudes of 23.5&deg; are the Tropics of Cancer and Capricorn, north and south of the Equator.</li>
<li>At 66.5&deg; are the Arctic and Antarctic Circles, to the north and south.</li>
<li>Latitudes are a measure of a location&rsquo;s distance from the Equator.</li>
</ul>
</li>
<li>During the solstice, the<strong> Earth&rsquo;s axis &mdash; around which the planet spins,</strong> completing one turn each day &mdash; is <strong>tilted in a way that the North Pole is tipped towards the sun</strong> and the South Pole is away from it.</li>
<li>Typically, this imaginary axis passes right through the middle of the Earth from top to bottom and is always<strong> tilted at 23.5 degrees with respect to the sun.</strong></li>
<li>At the<strong> Arctic Circle,</strong> the <strong>sun never sets during the solstice.</strong></li>
</ul>
</li>
<li><strong>Greater Amount of Energy:</strong><br />
<ul style="list-style-type: circle;">
<li>This day is characterised by a greater amount of energy received from the sun. According to <a href="/important-institutions/drishti-specials-important-institutions-international-institution/national-aeronautics-and-space-administration-nasa" target="_blank" rel="noopener"><strong>NASA (National Aeronautics and Space Administration)</strong></a>, the amount of incoming energy the Earth received from the sun on this day is 30% higher at the North Pole than at the Equator.</li>
<li>The maximum amount of sunlight received by the Northern Hemisphere during this time is usually on June 20, 21 or 22. In contrast, the <strong>Southern Hemisphere receives most sunlight on December 21, 22 or 23</strong> when the northern hemisphere has its longest nights&ndash; or the<strong> winter solstice.</strong></li>
</ul>
</li>
<li><strong>Geography Behind:</strong><br />
<ul style="list-style-type: circle;">
<li>The <strong>reason behind the changing lengths of the days </strong>is the<strong> Earth&rsquo;s tilt.</strong></li>
<li>The Earth&rsquo;s axis of rotation is tilted at an angle of 23.5&deg; to its orbital plane. This tilt, <strong>combined with factors such as Earth&rsquo;s spin and orbit,</strong> leads to variations in the duration of sunlight, due to which any location on the planet receives different lengths of days.<br />
<ul style="list-style-type: disc;">
<li>The Northern Hemisphere spends half the year tilted in the direction of the Sun, getting direct sunlight during long summer days. During the other half of the year, it tilts away from the Sun, and the days are shorter.</li>
</ul>
</li>
<li>The tilt is <strong>also responsible for the different seasons on Earth.</strong> This phenomenon causes the movement of the Sun from the northern to the southern hemisphere and vice versa bringing in seasonal changes in the year.</li>
</ul>
</li>
</ul>
<div class="border-bg">
<p><strong>The Equinox</strong></p>
<ul style="list-style-type: square;">
<li><strong>Twice each year,</strong> during the equinoxes (&ldquo;equal nights&rdquo;), Earth's axis is <strong>not pointed toward our Sun, but is perpendicular to the incoming rays.</strong></li>
<li>It results in a <strong>"nearly" equal amount of daylight and darkness at all latitudes.</strong></li>
<li>The<strong> vernal or spring equinox</strong> occurs in the northern hemisphere on March 20 or 21. September 22 or 23 marks the northern hemisphere <a href="/daily-updates/daily-news-analysis/autumnal-equinox-in-northern-hemisphere#:~:text=The%20word%20equinox%20is%20derived,are%20referred%20to%20as%20Equinoxes." target="_blank" rel="noopener"><strong>autumnal or fall equinox.</strong></a></li>
</ul>
</div>
<p><a href="https://indianexpress.com/article/explained/summer-solstice-explained-why-june-21-will-be-the-longest-day-of-the-year-in-northern-hemisphere-7367636/" target="_blank" rel="noopener"><strong>Source: IE</strong></a></p>',
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	(int) 8 => object(Cake\ORM\Entity) {

		'article_id' => (int) 8530,
		'category_id' => (int) 21,
		'title' => 'Black Carbon and Glacier Melting',
		'description' => '<h3>Why in News</h3>
<p>The report titled <strong>&ldquo;Glaciers of the Himalayas: Climate Change, Black Carbon and Regional Resilience&rdquo;</strong> says that the <a href="/to-the-points/paper1/glaciers-6" target="_blank" rel="noopener"><strong>glaciers</strong></a> are melting faster than the global average ice mass. However, the strong policy on <a href="/daily-updates/daily-news-analysis/concentration-of-black-carbon-on-gangotri-glacier" target="_blank" rel="noopener"><strong>black carbon</strong></a> can sharply cut glacier melt.</p>
<ul style="list-style-type: square;">
<li>The research report is <strong>released by the <a href="/important-institutions/drishti-specials-important-institutions-international-institution/world-bank-group" target="_blank" rel="noopener">World Bank</a></strong> and covers the <strong><a href="/daily-updates/daily-news-analysis/national-mission-on-sustaining-himalayan-ecosystem" target="_blank" rel="noopener">Himalaya</a>, Karakoram</strong>, and <a href="/daily-updates/daily-news-analysis/hindu-kush-himalayan-region" target="_blank" rel="noopener"><strong>Hindu Kush (HKHK)</strong></a> mountain ranges.</li>
</ul>
<div class="border-bg">
<p><strong>Black Carbon</strong></p>
<ul style="list-style-type: square;">
<li>Black carbon is <strong>a kind of an aerosol.</strong> <br />
<ul style="list-style-type: circle;">
<li>An <strong>aerosol</strong> is a suspension of fine solid particles or liquid droplets in the air.</li>
</ul>
</li>
<li>Among aerosols (such as brown carbon, sulphates), Black Carbon (BC) has been <strong>recognized as the second most important anthropogenic agent for climate change</strong> and the <strong>primary marker to understand the adverse effects caused by air pollution.</strong></li>
<li>It <strong>gets emitted</strong> from gas and diesel engines, coal-fired power plants, and other sources that burn fossil fuel. It <strong>comprises a significant portion of <a href="/daily-updates/daily-news-analysis/dashboard-for-monitoring-air-quality" target="_blank" rel="noopener">particulate matter or PM</a></strong>, which is an air pollutant.</li>
</ul>
<p><strong>HKHK Mountain Region:</strong></p>
<ul style="list-style-type: square;">
<li>HKHK Region <strong>spans eight countries</strong>; Afghanistan, Pakistan, India, Nepal, China, Bhutan, Bangladesh and Myanmar and also <strong>has some of the world&rsquo;s tallest mountains including <a href="/daily-updates/daily-news-analysis/new-height-for-mount-everest" target="_blank" rel="noopener">Mt. Everest</a> and K2.</strong></li>
<li>HKHK Glaciers <strong>feed into river systems</strong> including Ganga, Yangtze, Irrawaddy, and Mekong.<br />
<ul style="list-style-type: circle;">
<li>The water that runs down from glaciers <strong>feeds the agriculture</strong>, on which nearly 2 billion people are dependent upon.</li>
</ul>
</li>
<li>HKHK Region, also known as the <strong>third pole</strong>, along with China&rsquo;s Tien Shan Mountains holds most ice outside the North and the South Pole.</li>
</ul>
</div>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>About Black Carbon:</strong><br />
<ul style="list-style-type: circle;">
<li>BC is a <strong>short-lived pollutant</strong> that is the <strong>second-largest contributor to warming the planet behind carbon dioxide (CO<sub>2</sub>).</strong> <br />
<ul style="list-style-type: disc;">
<li>Unlike other greenhouse gas emissions, BC is <strong>quickly washed out and can be eliminated from the atmosphere if emissions stop.</strong></li>
<li>Unlike historical carbon emissions it is <strong>also a localised source with greater local impact.</strong></li>
</ul>
</li>
</ul>
</li>
<li><strong>Source of Black Carbon in Himalayan Region:</strong> <br />
<ul style="list-style-type: circle;">
<li><strong>Industry</strong> (primarily brick kilns) and <strong>residential burning of solid fuel</strong> together account for 45-66% of regional anthropogenic (man-made) BC deposition, followed by <strong>on-road diesel fuels</strong> (7-18%) and <strong>open burning</strong> (less than 3% in all seasons) in the region.</li>
</ul>
</li>
<li><strong>Impact of Deposits of BC:</strong> <br />
<ul style="list-style-type: circle;">
<li>It <strong>acts in two ways</strong> hastening the pace of glacier melt:<br />
<ul style="list-style-type: disc;">
<li>By decreasing surface reflectance of sunlight.</li>
<li>By raising the air temperature.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Rate of De-glaciation:</strong> <br />
<ul style="list-style-type: circle;">
<li>The rate of retreat of HKHK glaciers is <strong>estimated to be 0.3 metres per year in the west to 1.0 metre per year</strong> in the east.</li>
<li>Full implementation of <strong>current policies to mitigate BC can achieve a 23% reduction</strong> but <strong>enacting new policies</strong> and incorporating them through regional cooperation among countries can achieve enhanced benefits.<br />
<ul style="list-style-type: disc;">
<li><strong>National Mission on Sustaining Himalayan Ecosystem (NMSHE)</strong> is one such policy adopted in India. It is one of the eight missions under the <strong><a href="/to-the-points/Paper2/national-action-plan-on-climate-change" target="_blank" rel="noopener">National Action Plan on Climate Change (NAPCC)</a>.</strong></li>
</ul>
</li>
<li><strong>BC deposits can be sharply reduced</strong> through new, currently feasible policies <strong>by an additional 50%</strong> from current levels.</li>
</ul>
</li>
<li><strong>Impact of Glacier Melt:</strong><br />
<ul style="list-style-type: circle;">
<li>Glacier melt <strong>produces <a href="/daily-updates/daily-news-analysis/uttarakhand-flash-flood" target="_blank" rel="noopener">flash floods</a>, landslips, <a href="/daily-updates/daily-news-analysis/India%20lost%20One-Third%20of%20its%20Coastline%20Due%20to%20Soil%20Erosion" target="_blank" rel="noopener">soil erosion</a>, and <a href="/daily-updates/daily-news-analysis/himalayan-glaciers-impacted-by-climate-change" target="_blank" rel="noopener">glacial lake outburst floods (GLOF)</a>.</strong></li>
<li>In the short run, the higher volumes of melt water <strong>could replace receding groundwater downstream.</strong> But in the long run, decreased water availability would <strong>aggravate water shortage.</strong></li>
</ul>
</li>
<li><strong>Measures to be Taken:</strong><br />
<ul style="list-style-type: circle;">
<li>In the Himalayas, <strong>reducing black carbon emissions from cookstoves, diesel engines, and open burning</strong> would have the greatest impact and could significantly <strong>reduce radiative forcing</strong> and help to maintain a greater portion of Himalayan glacier systems. <br />
<ul style="list-style-type: disc;">
<li><strong>Radiative forcing is a measure of the change in energy balance</strong> as a result of a change in a forcing agent (e.g., greenhouse gases, aerosol, cloud, and surface albedo) to affect the global energy balance and contribute to climate change.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Steps to be Taken by Regional Governments:</strong><br />
<ul style="list-style-type: circle;">
<li>Review the <strong>policies on water management</strong>, with an emphasis on basin-based regulation and use of price signals (value of a particular action) for efficiency.</li>
<li>Careful <strong>planning and use of hydropower</strong> to reflect changes in water flows and availability.</li>
<li>Increasing the <strong>efficiency of brick kilns</strong> through proven technologies.</li>
<li>There must also be greater <strong>knowledge sharing</strong> in the region.</li>
</ul>
</li>
</ul>
<p><a href="https://www.thehindu.com/sci-tech/energy-and-environment/strong-policies-on-black-carbon-can-sharply-cut-glacier-melt-says-world-bank-study/article34719913.ece/amp/" target="_blank" rel="noopener"><strong>Source: TH</strong></a></p>',
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	(int) 9 => object(Cake\ORM\Entity) {

		'article_id' => (int) 8416,
		'category_id' => (int) 21,
		'title' => 'A-76: World’s Largest Iceberg',
		'description' => '<h3>Why in News</h3>
<p>An <strong>enormous iceberg 'A-76'</strong> has<strong> calved from the western side of the Ronne Ice Shelf,</strong> lying in the <strong>Weddell Sea, in <a href="/daily-updates/daily-news-analysis/covid-in-antarctica" target="_blank" rel="noopener">Antarctica</a>.</strong></p>
<ul style="list-style-type: square;">
<li>It measures around 4320 sq km in size &ndash; <strong>currently making it the largest berg in the world.</strong></li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1621591787_image7.jpg" target="_blank" rel="noopener"><strong><img class="content-img" src="http://www.drishtiias.com/images/uploads/1621591787_image7.jpg" style="display: block; margin-left: auto; margin-right: auto;" width="500" caption="false" /></strong></a></p>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>About A-76:</strong><br />
<ul style="list-style-type: circle;">
<li>The <strong>newly calved berg 'A-76'</strong> was spotted in recent satellite images captured by the <a href="/daily-updates/daily-news-analysis/sentinel-6-satellite-jason-cs-mission" target="_blank" rel="noopener"><strong>Copernicus Sentinel-1 mission.</strong></a><br />
<ul style="list-style-type: disc;">
<li>Sentinel-1 is one of the missions of the European Space Agency (ESA) under Copernicus initiative (an earth observation programme).</li>
</ul>
</li>
<li>It has <strong>surpassed the now second-place A-23A,</strong> about 3,380 sq km in size and also floating in the <strong>Weddell Sea.</strong></li>
</ul>
</li>
<li><strong>Iceberg:</strong><br />
<ul style="list-style-type: circle;">
<li>An iceberg is<strong> ice that broke off from glaciers or shelf ice</strong> and is floating in open water.</li>
<li>Icebergs<strong> travel with ocean currents</strong> and either get caught up in shallow waters or ground themselves.</li>
<li>The <strong>US National Ice Center (USNIC)</strong> is the<strong> only organisation</strong> that names and tracks Antarctic Icebergs.<br />
<ul style="list-style-type: disc;">
<li>Icebergs <strong>are named according to the Antarctic quadrant</strong> in which they are spotted.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Ice Shelves:</strong><br />
<ul style="list-style-type: circle;">
<li>An ice shelf is <strong>a floating extension of land ice.</strong> The Antarctic continent is surrounded by ice shelves.</li>
<li>The<strong> Ronne Ice Shelf</strong> on the flank of the Antarctic Peninsula is <strong>one of the largest of several enormous floating sheets of ice</strong> that connect to the<strong> continent's landmass and extend out into the surrounding seas.</strong></li>
</ul>
</li>
<li><strong>Iceberg Calving:</strong><br />
<ul style="list-style-type: circle;">
<li><strong>Meaning:</strong><br />
<ul style="list-style-type: disc;">
<li><a href="/daily-updates/daily-news-analysis/iceberg-a68a" target="_blank" rel="noopener"><strong>Calving</strong></a> is the <strong>glaciological term for the mechanical loss</strong> (or simply, breaking off) <strong>of ice</strong> from a glacier margin.</li>
<li>Calving is most common when a glacier flows into water (i.e. lakes or the ocean) but can also occur on dry land, where it is known as <strong>dry calving.</strong></li>
</ul>
</li>
<li><strong>Recent Cases of Calving:</strong><br />
<ul style="list-style-type: disc;">
<li>Up to the end of the 20<sup>th</sup> century, the <strong>Larsen Ice Shelf</strong> (on the West Antarctic Peninsula) had been stable for more than 10,000 years.<br />
<ul style="list-style-type: disc;">
<li>In 1995, however, a huge chunk broke off, followed by another in 2002.</li>
<li>This was followed by the <strong>breakup of the nearby Wilkins Ice Shelf in 2008 and 2009, and <a href="/daily-updates/daily-news-analysis/iceberg-a68a" target="_blank" rel="noopener">A68a</a> in 2017.</strong></li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1621592439_image4.png" target="_blank" rel="noopener"><strong><img class="content-img" src="http://www.drishtiias.com/images/uploads/1621592439_image4.png" style="display: block; margin-left: auto; margin-right: auto;" width="450" caption="false" /></strong></a></p>
<ul style="list-style-type: square;">
<li><strong>Concerns:</strong><br />
<ul style="list-style-type: circle;">
<li>Periodic calving off of large chunks of those shelves is part of a<strong> natural cycle,</strong> but the process has been <strong>accelerated by climate change.</strong></li>
<li><strong>Average sea levels</strong> have risen about <strong>nine inches since 1880,</strong> and about <strong>a quarter of that increase</strong> comes from <strong>ice melting in the Greenland and Antarctica ice sheets,</strong> along with land-based glaciers elsewhere.</li>
<li>According to a recent study, <strong>more ambitious national goals</strong> to cut <a href="/infographics/info-paper3/greenhouse-gas-emission" target="_blank" rel="noopener"><strong>greenhouse gas emissions</strong></a> and<strong> slow down climate change</strong> set recently are <strong>not enough to stop sea levels from rising.</strong><br />
<ul style="list-style-type: disc;">
<li>In fact, melting glaciers and ice sheets will raise sea levels twice as fast as they would if countries fulfilled their earlier pledges under the<a href="/daily-updates/daily-news-analysis/five-years-of-paris-climate-accord" target="_blank" rel="noopener"><strong> Paris Agreement.</strong></a></li>
</ul>
</li>
</ul>
</li>
</ul>
<p><a href="https://www.thehindu.com/news/international/antarctica-gives-birth-to-worlds-largest-iceberg/article34602010.ece" target="_blank" rel="noopener"><strong>Source: TH</strong></a></p>',
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	(int) 10 => object(Cake\ORM\Entity) {

		'article_id' => (int) 8318,
		'category_id' => (int) 21,
		'title' => 'Indian Monsoon Resembled Australian Monsoon',
		'description' => '<h3>Why in News</h3>
<p>According to a recent <strong>study based on fossil leaves, Indian monsoon 25 million years ago resembled present day Australia&rsquo;s.</strong></p>
<ul style="list-style-type: square;">
<li>Understanding the past dynamics of Indian monsoon <strong>will help in climate modelling for future monsoon prediction.</strong></li>
</ul>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>About the Study:</strong><br />
<ul style="list-style-type: circle;">
<li>The <strong>morphological characters of fossil leaves</strong> from <strong>different geological ages</strong> collected<strong> from Deccan Volcanic Province, East Garo Hills of Meghalaya, Gurha mine in Rajasthan and Makum Coalfield in Assam</strong> were analysed.<br />
<ul style="list-style-type: disc;">
<li>Plant leaf morphological characters such as apex, base and shape are <strong>ecologically tuned with the prevailing climatic conditions</strong> to adapt for all the seasons throughout the year.</li>
</ul>
</li>
<li>The results indicated that the <strong>fossil leaves from India were adapted to an Australian type of monsoon and not the current Indian monsoon system during its voyage.</strong><br />
<ul style="list-style-type: disc;">
<li>After <strong>India separated from Gondwana,</strong> its 9000 km northward <strong>voyage from the Southern Hemisphere to its modern position joined with Eurasia</strong> took 160 million years.</li>
</ul>
</li>
<li>The reconstructed temperature data show that<strong> the climate was warm (tropical to subtropical)</strong> at all the studied fossil sites with<strong> temperatures varying from 16.3&ndash;21.3 degrees C.</strong></li>
<li>All the fossil sites <strong>experienced high rainfall,</strong> which varied from 191.6 cm to 232 cm.</li>
</ul>
</li>
<li><strong>Separation of India from Gondwana:</strong><br />
<ul style="list-style-type: circle;">
<li>More than 140 million years ago,<strong> India was a part of the supercontinent called Gondwana.</strong><br />
<ul style="list-style-type: disc;">
<li>The <strong>Gondwana</strong> was composed of modern <strong>South America, Africa, Antarctica, and Australia.</strong></li>
<li><strong>Tethys Ocean -</strong> an immense body of water separated Gondwana from Eurasia.</li>
</ul>
</li>
<li>When this <strong>supercontinent split up, a tectonic plate composed of India and modern Madagascar</strong> started to<strong> drift away.</strong></li>
<li>Then, <strong>India split from Madagascar</strong> and <strong>drifted north-eastward</strong> with a velocity of about <strong>20 cm/year.</strong></li>
<li>The continent <strong>collided with Eurasia about 50 million years ago,</strong> giving<strong> rise to the Himalayas.</strong></li>
<li>Nowadays, <strong>India is still moving in the same direction</strong> but with <strong>a lower velocity of about 4 cm/year,</strong> due to the resistance of the Eurasian plate.</li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1620375815_image2.png" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1620375815_image2.png" style="display: block; margin-left: auto; margin-right: auto;" width="400" caption="false" /></a></p>
<h3>Indian Monsoon</h3>
<ul style="list-style-type: square;">
<li>The <strong>climate of India is described as the &lsquo;monsoon&rsquo; type.</strong> In Asia, this type of climate is found mainly in the south and the southeast.</li>
<li>Out of a total of 4 seasonal divisions of India, <strong><a href="/to-the-points/paper1/monsoon-2" target="_blank" rel="noopener">monsoon</a> occupies 2 divisions,</strong> namely,<br />
<ul style="list-style-type: circle;">
<li><strong>The southwest monsoon season -</strong> Rainfall received from the southwest monsoons is seasonal in character, which occurs between June and September.</li>
<li><strong>The retreating monsoon season -</strong> The months of October and November are known for retreating monsoons.</li>
</ul>
</li>
<li><strong>Factors Influencing Southwest Monsoon Formation:</strong><br />
<ul style="list-style-type: circle;">
<li><strong>The differential heating and cooling of land and water</strong> creates a low pressure on the landmass of India while the seas around experience comparatively high pressure.</li>
<li><strong>The shift of the position of Inter Tropical Convergence Zone (ITCZ)</strong> in summer, over the Ganga plain (this is the equatorial trough normally positioned about 5&deg;N of the equator. It is also known as the monsoon-trough during the monsoon season).</li>
<li><strong>The presence of the high-pressure area, east of Madagascar,</strong> approximately at 20&deg;S over the Indian Ocean. The intensity and position of this high-pressure area affect the Indian Monsoon.</li>
<li><strong>The Tibetan plateau</strong> gets intensely heated during summer, which results in strong vertical air currents and the formation of low pressure over the plateau at about 9 km above sea level.</li>
<li><strong>The movement of the westerly jet stream</strong> to the north of the Himalayas and the presence of the tropical easterly jet stream over the Indian peninsula during summer.</li>
<li><strong>Tropical Easterly Jet (African Easterly Jet).</strong></li>
<li><strong>El Nino/Southern Oscillation (SO):</strong> Normally when the tropical eastern south Pacific Ocean experiences high pressure, the tropical eastern Indian Ocean experiences low pressure. But in certain years, there is a reversal in the pressure conditions and the eastern Pacific has lower pressure in comparison to the eastern Indian Ocean. This periodic change in pressure conditions is known as the SO.</li>
</ul>
</li>
</ul>
<p><a href="https://www.thehindu.com/sci-tech/science/indian-monsoon-25-million-years-ago-resembled-present-day-australias/article34118683.ece" target="_blank" rel="noopener"><strong>Source: TH</strong></a></p>',
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	(int) 11 => object(Cake\ORM\Entity) {

		'article_id' => (int) 8286,
		'category_id' => (int) 21,
		'title' => 'Climate Change Causing Shift in Earth’s Axis',
		'description' => '<h3>Why in News</h3>
<p>A study published in Geophysical Research Letters of the American Geophysical Union (AGU) says that <strong>due to the significant melting of glaciers</strong> because of global temperature rise, <strong>Earth&rsquo;s axis of rotation has been moving more than usual</strong> since the 1990s.</p>
<ul style="list-style-type: square;">
<li>While this change is <strong>not expected to affect daily life</strong>, it can <strong>change the length of the day by a few milliseconds.</strong></li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1620037413_image%20 (1).png" target="_blank" rel="noopener"><strong><img class="content-img" src="http://www.drishtiias.com/images/uploads/1620037413_image  (1).png" style="display: block; margin-left: auto; margin-right: auto;" width="350" caption="false" /></strong></a></p>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>Earth&rsquo;s Axis of Rotation:</strong><br />
<ul style="list-style-type: circle;">
<li>It is the <strong>line along which it spins around itself</strong> as it revolves around the Sun.<br />
<ul style="list-style-type: disc;">
<li><strong>Earth's axial tilt</strong> (also known as the obliquity of the ecliptic) is about <strong>23.5 degrees.</strong> Due to this axial tilt, the sun shines on different latitudes at different angles throughout the year. This <strong>causes the seasons.</strong></li>
</ul>
</li>
<li>The <strong>points</strong> on which the <strong>axis intersects the planet&rsquo;s surface</strong> are the <strong>geographical north and south poles.</strong><br />
<ul style="list-style-type: disc;">
<li>The <strong>location of the poles is not fixed.</strong> The <strong>axis moves</strong> due to <strong>changes in how the Earth&rsquo;s mass is distributed</strong> around the planet. Thus, the <strong>poles move when the axis moves</strong>, and the movement is called <strong>&ldquo;polar motion&rdquo;.</strong></li>
<li>Generally, polar motion is <strong>caused by</strong> changes in the hydrosphere, atmosphere, oceans, or solid Earth. But now, climate change is adding to the degree with which the poles wander.</li>
</ul>
</li>
<li>According to NASA, data from the <strong>20<sup>th</sup> century</strong> shows that the <strong>spin axis drifted about 10 centimetres per year.</strong> Meaning over a century, <strong>polar motion exceeds 10 metres.</strong></li>
</ul>
</li>
<li><strong>Findings from the New Study:</strong><br />
<ul style="list-style-type: circle;">
<li>Since the <strong>1990s, climate change has caused billions of tonnes of glacial ice to melt</strong> into oceans. This has <strong>caused the Earth&rsquo;s poles to move in new directions.</strong></li>
<li>The <strong>north pole has shifted in a new eastward direction</strong> since the 1990s, <strong>because of changes in the hydrosphere</strong> (meaning the way in which water is stored on Earth).</li>
<li>From 1995 to 2020, the average speed of drift was <strong>17 times faster</strong> than from 1981 to 1995.</li>
<li>Also, in the last four decades, the <strong>poles moved by about 4 metres in distance.</strong></li>
<li>The calculations were based on satellite data from <strong>NASA&rsquo;s Gravity Recovery and Climate Experiment (GRACE) mission.</strong></li>
<li><strong>Causes of Polar Drift:</strong><br />
<ul style="list-style-type: disc;">
<li><strong>Ice Melting:</strong><br />
<ul style="list-style-type: disc;">
<li>The faster ice melting under global warming was the most likely cause of the directional change of the polar drift in the 1990s.</li>
<li>As glaciers melt, water mass redistributes, causing shifts in the planet's axis.</li>
</ul>
</li>
<li><strong>Change in Non-Glacial Regions (Terrestrial Water Storage):</strong><br />
<ul style="list-style-type: disc;">
<li>Due to climate change and unsustainable consumption of groundwater for irrigation and other anthropogenic activities.</li>
</ul>
</li>
<li><strong>Groundwater Depletion:</strong><br />
<ul style="list-style-type: disc;">
<li>As millions of tonnes of water from below the land is pumped out every year for drinking, industries or agriculture, most of it eventually joins the sea, thus redistributing the planet&rsquo;s mass.</li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
</ul>
<p><a href="https://indianexpress.com/article/explained/explained-what-new-research-says-about-climate-change-causing-a-shift-in-earths-axis-7299258/" target="_blank" rel="noopener"><strong>Source: IE</strong></a></p>',
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	(int) 12 => object(Cake\ORM\Entity) {

		'article_id' => (int) 8262,
		'category_id' => (int) 21,
		'title' => 'Assam Earthquake',
		'description' => '<h3>Why in News</h3>
<p>Recently, a powerful earthquake <strong>measuring 6.4 on the Richter Scale</strong> jolted Assam and other parts of Northeast.</p>
<ul style="list-style-type: square;">
<li>According to the <strong>National Centre for Seismology (NCS)</strong> report, the tremors have been attributed to <strong>Kopili Fault zone closer to Himalayan Frontal Thrust (HFT).</strong><br />
<ul style="list-style-type: circle;">
<li>NCS is the <strong>nodal agency</strong> <strong>of the Government of India for monitoring earthquake activity in the country.</strong> It comes under the <strong>Ministry of Earth Sciences.</strong></li>
</ul>
</li>
</ul>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>Himalayan Frontal Thrust (HFT):</strong><br />
<ul style="list-style-type: circle;">
<li>HFT, also known as the <strong>Main Frontal Thrust (MFT)</strong>, is a geological fault along the boundary of the <strong>Indian and Eurasian tectonic plates.</strong></li>
</ul>
</li>
<li><strong>Kopili Fault Zone:</strong><br />
<ul style="list-style-type: circle;">
<li>The Kopili fault zone is a 300 km long and 50 km wide lineament (linear feature) extending from the <strong>western part of Manipur up to the tri-junction of Bhutan, Arunachal Pradesh and Assam.</strong></li>
<li>The area is seismically very active falling in the highest <strong>Seismic Hazard zone V</strong> associated with collisional tectonics where <strong>Indian plate subducts beneath the Eurasian Plate.</strong><br />
<ul style="list-style-type: disc;">
<li>Subduction is a geological process in which one crustal plate is forced below the edge of another.</li>
<li>Squeezed between the subduction and collision zones of the Himalayan belt and Sumatran belt, the North East is highly prone to earthquake occurrences.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Fault:</strong><br />
<ul style="list-style-type: circle;">
<li>A fault is a fracture along which the blocks of crust on either side have moved relative to one another parallel to the fracture.</li>
<li>When an earthquake occurs, the rock on one side of the fault slips with respect to the other.</li>
<li>The fault surface can be <strong>vertical, horizontal, or at some angle to the surface of the earth.</strong></li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1619689044_image%201.png" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1619689044_image 1.png" style="display: block; margin-left: auto; margin-right: auto;" width="450" caption="false" /></a></p>
<ul style="list-style-type: square;">
<li><strong>Tectonic Plates:</strong><br />
<ul style="list-style-type: circle;">
<li>A <a href="/to-the-points/paper1/tectonic-plates" target="_blank" rel="noopener"><strong>tectonic plate</strong></a> (also called lithospheric plate) is a massive, irregularly-shaped slab of solid rock, generally composed of both continental and oceanic lithosphere.</li>
<li>A tectonic plate may be a continental plate or an oceanic plate, depending on which of the two occupies the larger portion of the plate.</li>
<li>The Pacific plate is largely an oceanic plate whereas the Eurasian plate is a continental plate.</li>
</ul>
</li>
</ul>
<div class="border-bg">
<p><strong>Earthquake</strong></p>
<ul style="list-style-type: square;">
<li>An earthquake in simple words is the shaking of the earth. It is a natural event. It is caused due to release of energy, which generates waves that travel in all directions.</li>
<li>The vibrations called <strong>seismic waves</strong> are generated from earthquakes that travel through the Earth and are recorded on instruments called seismographs.</li>
<li>The location below the earth&rsquo;s surface where the earthquake starts is called the <strong>hypocenter,</strong> and the location directly above it on the surface of the earth is called the <strong>epicenter.</strong></li>
<li><strong><a href="/to-the-points/paper1/earthquake-4#:~:text=Fault%20Zones%3A,the%20friction%20locks%20them%20together." target="_blank" rel="noopener">Types of Earthquake</a>:</strong> Fault Zones, Tectonic Earthquakes, Volcanic Earthquake, Human Induced Earthquakes.</li>
</ul>
<p><strong>Seismic Hazard Map of India</strong></p>
<ul style="list-style-type: square;">
<li>India is one of the highly earthquake affected countries because of the presence of technically active young fold mountains - Himalaya.</li>
<li>India has been divided into <strong>four seismic zones (II, III, IV, and V)</strong> based on scientific inputs relating to seismicity, earthquakes occurred in the past and tectonic setup of the region.<br />
<ul style="list-style-type: circle;">
<li>Previously, earthquake zones were divided into five zones with respect to the severity of the earthquakes but the <a href="/daily-updates/daily-news-analysis/bureau-of-indian-standards-bis-act-2016" target="_blank" rel="noopener"><strong>Bureau of Indian Standards</strong></a> (BIS) grouped the country into four seismic zones by unifying the first two zones.</li>
<li>BIS is the official agency for publishing the seismic hazard maps and codes.</li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1619689133_image%202.png" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1619689133_image 2.png" style="display: block; margin-left: auto; margin-right: auto;" width="450" caption="false" /></a></p>
<ul style="list-style-type: square;">
<li><strong>Seismic Zone II:</strong><br />
<ul style="list-style-type: circle;">
<li>Area with minor damage earthquakes corresponding to intensities V to VI of MM scale (MM-Modified Mercalli Intensity scale).</li>
</ul>
</li>
<li><strong>Seismic Zone III:</strong><br />
<ul style="list-style-type: circle;">
<li>Moderate damage corresponding to intensity VII of MM scale.</li>
</ul>
</li>
<li><strong>Seismic Zone IV:</strong><br />
<ul style="list-style-type: circle;">
<li>Major damage corresponding to intensity VII and higher of MM scale.</li>
</ul>
</li>
<li><strong>Seismic Zone V:</strong><br />
<ul style="list-style-type: circle;">
<li>Area determined by pro seismically of certain major fault systems and is seismically the most active region.</li>
<li>Earthquake zone V is the most vulnerable to earthquakes, where historically some of the country&rsquo;s most powerful shocks have occurred.</li>
<li>Earthquakes with magnitudes in excess of 7.0 have occured in these areas, and have had intensities higher than IX.</li>
</ul>
</li>
</ul>
</div>
<p><a href="https://indianexpress.com/article/explained/explained-in-assam-earthquake-reminder-of-seismic-hazard-along-hft-faultline-7292770/" target="_blank" rel="noopener"><strong>Source: IE</strong></a></p>',
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	(int) 13 => object(Cake\ORM\Entity) {

		'article_id' => (int) 8239,
		'category_id' => (int) 26,
		'title' => 'Types of Forests in India',
		'description' => '<h3>Introduction</h3>
<ul style="list-style-type: square;">
<li><strong>Definition of Forest:</strong>
<ul style="list-style-type: circle;">
<li>At present, in India, there is no clear nationally-accepted definition of &lsquo;forest&rsquo;.</li>
<li>States are responsible for determining their definition of forests.</li>
<li>The prerogative of the states to define forests stems from a 1996 Supreme Court order called the <strong>T.N. Godavarman Thirumulkpad vs the Union of India</strong> judgment.
<ul style="list-style-type: disc;">
<li>In the judgement, the Supreme Court interpreted that the word &ldquo;forest&rdquo; must be understood according to its &ldquo;dictionary meaning&rdquo;.</li>
<li>This description covers all statutorily recognised forests, whether designated as reserved, protected or otherwise.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Constitutional Provisions:</strong>
<ul style="list-style-type: circle;">
<li>Forests are included in the <strong>Concurrent List</strong> in the (Seventh Schedule) of the Constitution of India.</li>
<li>Through the<a href="/to-the-points/Paper2/major-constitutional-amendments-part-2" target="_blank" rel="noopener"><strong> 42<sup>nd</sup> Amendment Act</strong></a>, 1976 Forests and Protection of Wild Animals and Birds were transferred from State to Concurrent List.</li>
<li><strong>Article 51 A (g)</strong> of the Constitution states that it shall be the<a href="/daily-updates/daily-news-analysis/fundamental-duties" target="_blank" rel="noopener"><strong> fundamental duty</strong> </a>of every citizen to protect and improve the natural environment including forests and Wildlife.</li>
<li><strong>Article 48 A</strong> in the <a href="/mains-practice-question/question-180" target="_blank" rel="noopener"><strong>Directive Principles of State policy</strong></a>, mandates that the State shall endeavor to protect and improve the environment and to safeguard the forests and wildlife of the country.</li>
</ul>
</li>
<li><strong>Statute:</strong>
<ul style="list-style-type: circle;">
<li>India&rsquo;s forests are currently governed by the<a href="/daily-updates/daily-news-analysis/review-of-national-forest-policy-1988" target="_blank" rel="noopener"><strong> National Forest Policy, 1988</strong></a> which has environmental balance and livelihood at its centre.</li>
</ul>
</li>
<li><strong>Forestry Report:</strong>
<ul style="list-style-type: circle;">
<li>According to <a href="/daily-updates/daily-news-analysis/india-state-of-forest-report-isfr-2019" target="_blank" rel="noopener"><strong>India State of Forest Report, 2019,</strong></a> tree and forest cover together made up 24.56% (8,07,276 sq km) of India's area.</li>
<li>The country is pursuing a long-term goal of having 33 percent of its land under forest cover.</li>
</ul>
</li>
</ul>
<h3>Classification of Forests</h3>
<p><strong>On Administration-Basis</strong></p>
<table border="1" style="border-collapse: collapse; width: 100%;">
<tbody>
<tr style="height: 19px;">
<td style="width: 33.3333%; height: 19px; background-color: #132b18; text-align: center;"><span style="color: #ffffff;"><strong>Reserved Forests</strong></span></td>
<td style="width: 33.3333%; height: 19px; background-color: #132b18; text-align: center;"><span style="color: #ffffff;"><strong>Protected Forests</strong></span></td>
<td style="width: 33.3333%; height: 19px; background-color: #132b18; text-align: center;"><span style="color: #ffffff;"><strong>Unprotected Forests</strong></span></td>
</tr>
<tr style="height: 67px;">
<td style="width: 33.3333%; height: 67px; text-align: left; vertical-align: top; background-color: #f5f7ff;">
<ul style="list-style-type: square;">
<li>Under direct supervision of the Government.</li>
</ul>
</td>
<td style="width: 33.3333%; height: 67px; text-align: left; vertical-align: top; background-color: #f5f7ff;">
<ul style="list-style-type: square;">
<li>Looked after by the government.</li>
</ul>
</td>
<td style="width: 33.3333%; height: 67px; text-align: left; vertical-align: top; background-color: #f5f7ff;">
<ul style="list-style-type: square;">
<li>Unclassified Forests.</li>
</ul>
</td>
</tr>
<tr style="height: 133px;">
<td style="width: 33.3333%; height: 133px; text-align: left; vertical-align: top; background-color: #f5f7ff;">
<ul style="list-style-type: square;">
<li>No public entry allowed for the commercial purpose of cattle grazing.</li>
</ul>
</td>
<td style="width: 33.3333%; height: 133px; text-align: left; vertical-align: top; background-color: #f5f7ff;">
<ul style="list-style-type: square;">
<li>Local people are allowed to collect forest produce and cattle grazing without causing any serious damage.</li>
</ul>
</td>
<td style="width: 33.3333%; height: 133px; text-align: left; vertical-align: top; background-color: #f5f7ff;">
<ul style="list-style-type: square;">
<li>No restriction on cutting trees or grazing cattle.</li>
</ul>
</td>
</tr>
<tr>
<td style="width: 33.3333%; text-align: left; vertical-align: top; background-color: #f5f7ff;">
<ul style="list-style-type: square;">
<li>53% of the<strong> Total Forest Area (TFA)</strong> of the country under this category.</li>
</ul>
</td>
<td style="width: 33.3333%; text-align: left; vertical-align: top; background-color: #f5f7ff;">
<ul style="list-style-type: square;">
<li>Occupy about 29% of the TFA.</li>
</ul>
</td>
<td style="width: 33.3333%; text-align: left; vertical-align: top; background-color: #f5f7ff;">
<ul style="list-style-type: square;">
<li>Occupy 18% of the TFA.</li>
</ul>
</td>
</tr>
</tbody>
</table>
<p><strong>Classification as per Constitution of India</strong></p>
<table border="1" style="border-collapse: collapse; width: 100%;">
<tbody>
<tr style="height: 19px;">
<td style="width: 33.3333%; vertical-align: top; text-align: center; height: 19px; background-color: #322554;">
<p><span style="color: #ffffff;"><strong>State Forests</strong></span></p>
</td>
<td style="width: 33.3333%; vertical-align: top; text-align: center; height: 19px; background-color: #322554;">
<p><span style="color: #ffffff;"><strong>Commercial Forests</strong></span></p>
</td>
<td style="width: 33.3333%; vertical-align: top; text-align: center; height: 19px; background-color: #322554;">
<p><span style="color: #ffffff;"><strong>Private Forests</strong></span></p>
</td>
</tr>
<tr style="height: 133px;">
<td style="width: 33.3333%; text-align: left; vertical-align: top; height: 73px; background-color: #f4edfa;">
<ul style="list-style-type: square;">
<li>Include almost all important forest areas of the country and are under full control of the government (state/central).</li>
</ul>
</td>
<td style="width: 33.3333%; text-align: left; vertical-align: top; height: 73px; background-color: #f4edfa;">
<ul style="list-style-type: square;">
<li>Owned and administered by local bodies (municipal corporations, village panchayats, district boards etc.)</li>
</ul>
</td>
<td style="width: 33.3333%; text-align: left; vertical-align: top; height: 73px; background-color: #f4edfa;">
<ul style="list-style-type: square;">
<li>Under private ownership.</li>
</ul>
</td>
</tr>
<tr style="height: 67px;">
<td style="width: 33.3333%; text-align: left; vertical-align: top; height: 67px; background-color: #f4edfa;">
<ul style="list-style-type: square;">
<li>Cover almost 94% of the TFA.</li>
</ul>
</td>
<td style="width: 33.3333%; text-align: left; vertical-align: top; height: 67px; background-color: #f4edfa;">
<ul style="list-style-type: square;">
<li>Cover 5% of the TFA.</li>
</ul>
</td>
<td style="width: 33.3333%; text-align: left; vertical-align: top; height: 67px; background-color: #f4edfa;">
<ul style="list-style-type: square;">
<li>Cover slightly more than 1% of the TFA.</li>
</ul>
</td>
</tr>
</tbody>
</table>
<p><strong>On Merchantability</strong></p>
<table border="1" style="border-collapse: collapse; width: 100%;">
<tbody>
<tr style="height: 19px;">
<td style="width: 50%; height: 19px; text-align: center; background-color: #3b5248;">
<p><span style="color: #ffffff;"><strong>Merchantable</strong></span></p>
</td>
<td style="width: 50%; height: 19px; text-align: center; background-color: #3b5248;">
<p><span style="color: #ffffff;"><strong>Non- Merchantable</strong></span></p>
</td>
</tr>
<tr style="height: 52px;">
<td style="width: 50%; height: 52px; background-color: #e7ffe6;">
<ul style="list-style-type: square;">
<li>Forests that are accessible.</li>
</ul>
</td>
<td style="width: 50%; height: 52px; background-color: #e7ffe6;">
<ul style="list-style-type: square;">
<li>Forests that are situated at high mountainous peaks; non accessible.</li>
</ul>
</td>
</tr>
<tr style="height: 19px;">
<td style="width: 50%; height: 19px; background-color: #e7ffe6;">
<ul style="list-style-type: square;">
<li>Cover 82% of the TFA.</li>
</ul>
</td>
<td style="width: 50%; height: 19px; background-color: #e7ffe6;">
<ul style="list-style-type: square;">
<li>Cover 18% of the TFA.</li>
</ul>
</td>
</tr>
</tbody>
</table>
<ul style="list-style-type: square;"></ul>
<p><strong>Based on Composition</strong></p>
<table border="1" style="border-collapse: collapse; width: 100%;">
<tbody>
<tr style="height: 19px;">
<td style="width: 50%; height: 19px; vertical-align: top; text-align: center; background-color: #fac014;">
<p><span style="color: #000000;"><strong>Coniferous Forests</strong></span></p>
</td>
<td style="width: 50%; height: 19px; vertical-align: top; text-align: center; background-color: #fac014;">
<p><span style="color: #000000;"><strong>Broad-Leaf Forests</strong></span></p>
</td>
</tr>
<tr style="height: 45px;">
<td style="width: 50%; height: 45px; text-align: left; vertical-align: top; background-color: #fffaed;">
<ul style="list-style-type: square;">
<li>Temperate Forests</li>
</ul>
</td>
<td style="width: 50%; height: 45px; text-align: left; vertical-align: top; background-color: #fffaed;">
<ul style="list-style-type: square;">
<li>Tropical and subtropical monsoon forests.</li>
</ul>
</td>
</tr>
<tr style="height: 19px;">
<td style="width: 50%; height: 19px; text-align: left; vertical-align: top; background-color: #fffaed;">
<ul style="list-style-type: square;">
<li>Found in middle and upper elevations of the eastern Middle Himalayas and N-E Indian states like Arunachal Pradesh.</li>
</ul>
</td>
<td style="width: 50%; height: 19px; text-align: left; vertical-align: top; background-color: #fffaed;">
<ul style="list-style-type: square;">
<li>Found in the plateaus, plains and mountainous areas of the country.</li>
</ul>
</td>
</tr>
<tr style="height: 10px;">
<td style="width: 50%; height: 10px; text-align: left; vertical-align: top; background-color: #fffaed;">
<ul style="list-style-type: square;">
<li>Cover 6.50% of the TFA of the country.</li>
</ul>
</td>
<td style="width: 50%; height: 10px; text-align: left; vertical-align: top; background-color: #fffaed;">
<ul style="list-style-type: square;">
<li>Cover about 94% of the TFA of the country.</li>
</ul>
</td>
</tr>
</tbody>
</table>
<ul style="list-style-type: square;"></ul>
<h3>Based on Average Annual Rainfall</h3>
<p>In India, the Forests, on the basis of average annual rainfall, can be categorised broadly into five categories:</p>
<p><strong>Tropical Evergreen Forests</strong></p>
<ul style="list-style-type: square;">
<li><strong>Moist Evergreen Forests:</strong>
<ul style="list-style-type: circle;">
<li><strong>Region:</strong> Found in southern India along the <strong>Western Ghats, Andaman and Nicobar Islands</strong> and<strong> north-eastern region.</strong></li>
<li><strong>Climatic Conditions:</strong> Found in <strong>warm and humid areas</strong> with an annual precipitation of over 200 cm and mean annual temperature above 22&deg;C.</li>
<li><strong>Trees:</strong> In these forests, trees reach great heights up to 60 m or above.
<ul style="list-style-type: disc;">
<li>There is no definite time for trees to shed their leaves, flowering and fruition; <strong>these forests appear green all the year round.</strong></li>
<li>Species found in these forests include Rosewood, Mahogany, Aini, Ebony, etc.</li>
<li>The more common trees that are found here are the jackfruit, betel nut palm, jamun, mango, and hollock.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Semi Evergreen Forests:</strong>
<ul style="list-style-type: circle;">
<li><strong>Region:</strong> Found in the less rainy parts of the regions where moist evergreen forests are found; <strong>Western Ghats, Andaman and Nicobar Islands, and the Eastern Himalayas.</strong></li>
<li><strong>Trees:</strong> Such forests have a mixture of moist evergreen and moist deciduous trees.
<ul style="list-style-type: disc;">
<li>The under growing climbers provide an evergreen character to these forests.</li>
<li>Main species are white cedar, hollock and kail.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Dry evergreen:</strong>
<ul style="list-style-type: circle;">
<li><strong>Region:</strong> Found in the <strong>Shivalik Hills</strong> and <strong>foothills of the Himalayas</strong> up to a height of 1000 metres in the north.
<ul style="list-style-type: disc;">
<li>Found along Andhra Pradesh and Karnataka coast in the south.</li>
</ul>
</li>
<li><strong>Climatic Conditions:</strong> Usually have a prolonged hot and dry season and a cold winter.</li>
<li><strong>Trees:</strong> Have mainly hard-leaved evergreen trees with fragrant flowers, along with a few deciduous trees.
<ul style="list-style-type: disc;">
<li>Trees have a varnished look.</li>
<li>Some of the more common ones are the pomegranate, olive, and oleander.</li>
</ul>
</li>
</ul>
</li>
</ul>
<p><strong>Tropical Deciduous Forests (Monsoon Forests)</strong></p>
<ul style="list-style-type: square;">
<li><strong>Moist Deciduous Forests:</strong>
<ul style="list-style-type: circle;">
<li><strong>Region:</strong> These forests are found in the <strong>north-eastern states</strong> along the <strong>foothills of Himalayas, eastern slopes of the Western Ghats</strong> and <strong>Odisha.</strong></li>
<li><strong>Rainfall:</strong> Found in the regions which record<strong> rainfall between 100-200 cm.</strong></li>
<li><strong>Trees:</strong> Tall trees with broad, branched trunks.
<ul style="list-style-type: disc;">
<li>Some of the taller trees shed their leaves in the dry season.</li>
<li><strong>Teak, sal, shisham, hurra, mahua, amla, semul, kusum, and sandalwood</strong> etc. are the main species of these forests.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Dry Deciduous Forests:</strong>
<ul style="list-style-type: circle;">
<li><strong>Region:</strong> Found throughout the northern part of the country except in the north-east.
<ul style="list-style-type: disc;">
<li>Also found in Madhya Pradesh, Gujarat, Andhra Pradesh, Karnataka, and Tamil Nadu.</li>
</ul>
</li>
<li><strong>Rainfall:</strong> Covers vast areas of the country, where rainfall ranges between 70 -100 cm.
<ul style="list-style-type: disc;">
<li>On the wetter margins, it has a transition to the moist deciduous, while on the drier margins to thorn forests.</li>
</ul>
</li>
<li><strong>Trees:</strong> As the dry season begins, the trees shed their leaves completely and the forest appears like a vast grassland with naked trees all around.
<ul style="list-style-type: disc;">
<li><strong>Tendu, palas, amaltas, bel, khair, axlewood,</strong> etc. are the common trees of these forests.</li>
</ul>
</li>
</ul>
</li>
</ul>
<p><strong>Thorn Forests</strong></p>
<ul style="list-style-type: square;">
<li><strong>Rainfall:</strong> The forests occur in the areas that receive<strong> annual rainfall less than 50cm.</strong></li>
<li><strong>Regions:</strong> This type is found in areas with black soil: North, West, Central, and South India.
<ul style="list-style-type: circle;">
<li>Includes semi-arid areas of south west Punjab, Haryana, Rajasthan, Gujarat, Madhya Pradesh and Uttar Pradesh.</li>
</ul>
</li>
<li><strong>Trees:</strong> The trees do not grow beyond 10 metres and consist of a variety of grasses and shrubs. Spurge, caper, and cactus are typically found in this region.
<ul style="list-style-type: circle;">
<li>The plants remain leafless for most part of the year.</li>
<li>Babul, Acacia, Kokko, Khair, Khajuri, Ber, Neem, Khejri, Palas, etc.are common species of the forests.</li>
</ul>
</li>
</ul>
<p><strong>Montane Forests</strong></p>
<ul style="list-style-type: square;">
<li><strong>Montane Wet Temperate Forests:</strong>
<ul style="list-style-type: circle;">
<li><strong>Region:</strong> Occur in the northern and southern India.
<ul style="list-style-type: disc;">
<li>In the North, it is found in the region to the<strong> east of Nepal into Arunachal Pradesh,</strong> at a height of 1800&ndash;3000 metres, receiving a<strong> minimum rainfall of 200 cm.</strong></li>
<li>In the South, it is found in parts of the<strong> Nilgiri Hills, the higher reaches of Kerala.</strong></li>
</ul>
</li>
<li><strong>Trees:</strong> The forests in the northern region are denser than in the South.
<ul style="list-style-type: disc;">
<li>This is because over time the original trees have been replaced by fast-growing varieties such as the eucalyptus.</li>
<li>Rhododendrons, Champa and a variety of ground flora can be found here.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Montane Subtropical Forests:</strong>
<ul style="list-style-type: circle;">
<li><strong>Climatic Conditions:</strong> Found in the region where<strong> average rainfall is 100-200 cm</strong> and temperature varies between 15&deg;C to 22&deg;C.</li>
<li><strong>Region:</strong> Found in <strong>north-western Himalayas</strong> (except Ladakh and Kashmir), Himachal Pradesh, Uttarakhand, Sikkim and Arunachal Pradesh.</li>
<li><strong>Trees:</strong> Chir (Pine) is the main tree but Oak, Jamun and Rhododendron are also found in these forests.</li>
</ul>
</li>
<li><strong>Himalayan Forests:</strong>
<ul style="list-style-type: circle;">
<li><strong>Himalayan Moist Forests:</strong>
<ul style="list-style-type: disc;">
<li><strong>Region:</strong> Found in Jammu &amp; Kashmir, Himachal Pradesh, Uttarakhand and northern hilly parts of Bengal.</li>
<li><strong>Elevation:</strong> Found in the belt where altitude varies between 1000-2000 m.</li>
<li><strong>Trees:</strong> Oak, chestnut, chir, sal, shrubs and nutritious grasses.</li>
</ul>
</li>
<li><strong>Himalayan Dry Temperate:</strong>
<ul style="list-style-type: disc;">
<li><strong>Region:</strong> J&amp;K, Chamba, Lahaul &amp; Kinnaur districts (Himachal Pradesh) and Sikkim.</li>
<li><strong>Trees:</strong> Mainly coniferous; deodar, oak, chilgoza, maple, olive, mulberry and willow.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Alpine and Subalpine Forests:</strong>
<ul style="list-style-type: circle;">
<li><strong>Elevation:</strong> In the higher reaches, there is a transition to Alpine forests and pastures occurring at altitudes of 2,500-4,000 m.
<ul style="list-style-type: disc;">
<li>Sub alpine forests extend from Kashmir to Arunachal Pradesh between 2900 to 3500 metres.</li>
</ul>
</li>
<li><strong>Trees:</strong> In the Western Himalayas, the vegetation consists mainly of juniper, rhododendron, willow, and black currant.
<ul style="list-style-type: disc;">
<li>In the eastern parts, red fir, black juniper, birch, and larch are the common trees.</li>
</ul>
</li>
</ul>
</li>
</ul>
<p><strong>Littoral/Swamp Forests</strong></p>
<ul style="list-style-type: square;">
<li><strong>Region:</strong> Found along the Andaman and Nicobar Islands and the delta area of the Ganga and the Brahmaputra.
<ul style="list-style-type: circle;">
<li>Other areas of significance are the Mahanadi, the Godavari and the Krishna deltas.</li>
</ul>
</li>
<li><strong>Trees:</strong> Some of these forests are dense and impenetrable. Only a limited number of plants are found in these evergreen forests.
<ul style="list-style-type: circle;">
<li>They have roots that consist of soft tissue so that the plant can breathe in the water.</li>
<li>It consists mainly of whistling pines, mangrove dates, palms, and bulletwood.</li>
</ul>
</li>
<li><strong>Mangroves in India:</strong> In India, the mangrove forests spread over 6,740 sq. km which is 7% of the world&rsquo;s mangrove forests.
<ul style="list-style-type: circle;">
<li>The forests stabilise the shoreline and protect the coastal areas from erosion.</li>
<li><a href="/daily-updates/daily-news-analysis/sundarbans-1" target="_blank" rel="noopener"><strong>Sunderbans</strong></a><strong> along the Ganges delta is the largest tidal forest in the world.</strong></li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1619435891_image5.jpg" target="_blank" rel="noopener"><strong><img class="content-img" src="http://www.drishtiias.com/images/uploads/1619435891_image5.jpg" style="display: block; margin-left: auto; margin-right: auto;" width="600" caption="false" /></strong></a></p>',
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	(int) 14 => object(Cake\ORM\Entity) {

		'article_id' => (int) 8187,
		'category_id' => (int) 21,
		'title' => 'Sulphur Dioxide Emissions from Caribbean Volcano ',
		'description' => '<h3>Why in News</h3>
<p>The <a href="/daily-updates/daily-news-analysis/sulfur-dioxide-emission-norms-delayed#:~:text=India%27s%20sulphur%20dioxide%20(SO2,largest%20emitter%20of%20SO2." target="_blank" rel="noopener"><strong>Sulphur Dioxide (SO<sub>2</sub>) emissions</strong></a> <strong>from a <a href="/daily-updates/daily-news-analysis/sangay-volcano-ecuador" target="_blank" rel="noopener">volcanic eruption</a> in the Caribbean (La Soufriere Volcano)</strong> have reached India, sparking fear of <strong>increased <a href="/daily-updates/daily-news-editorials/air-pollution-concerted-efforts" target="_blank" rel="noopener">pollution</a> levels</strong> in the northern parts of the country and <strong>acid rain.</strong></p>
<ul style="list-style-type: square;">
<li>The <strong>Caribbean is the region</strong> roughly south of the United States, east of Mexico and north of Central and South America, consisting of the Caribbean Sea and its islands.</li>
</ul>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>About La Soufriere Volcano:</strong><br />
<ul style="list-style-type: circle;">
<li>It is <strong>an active stratovolcano</strong> on the <strong>Caribbean island of Saint Vincent</strong> in Saint Vincent and the Grenadines.<br />
<ul style="list-style-type: disc;">
<li>A <strong>stratovolcano</strong> is a tall, conical volcano composed of one layer of hardened lava, tephra, and volcanic ash. These volcanoes are characterized by a steep profile and periodic, explosive eruptions.</li>
<li>Saint Vincent and the Grenadines, <strong>located in the southern Caribbean</strong>, consists of more than 30 islands and cays, nine of which are inhabited.</li>
</ul>
</li>
<li>It is the <strong>highest peak in Saint Vincent</strong> and has had five recorded explosive eruptions since 1718, most recently in April 2021.<br />
<ul style="list-style-type: disc;">
<li>The last time the volcano had <strong>erupted was in 1979.</strong></li>
</ul>
</li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1618901971_image%202.jpg" target="_blank" rel="noopener"><strong><img class="content-img" src="http://www.drishtiias.com/images/uploads/1618901971_image 2.jpg" width="450" caption="false" style="display: block; margin-left: auto; margin-right: auto;" /></strong></a></p>
<ul style="list-style-type: square;">
<li><strong>Impact of the Eruption on Global Temperatures:</strong><br />
<ul style="list-style-type: circle;">
<li><strong>Volcanic emissions</strong> reaching the stratosphere <strong>can have a cooling effect on global temperatures.</strong></li>
<li>The most significant climate impacts from volcanic injections into the stratosphere come from the <strong>conversion of sulphur dioxide</strong> to <strong>sulphuric acid</strong>, which condenses rapidly in the stratosphere to form <strong>fine sulphate aerosols.</strong><br />
<ul style="list-style-type: disc;">
<li>The <strong>aerosols increase</strong> the <strong>reflection of radiation</strong> from the Sun back into space, <strong>cooling the Earth&rsquo;s</strong> lower atmosphere or troposphere.</li>
<li>Bigger eruptions during the past century have caused a decrease in temperature of <strong>0.27 degree Celsius</strong> or more on the Earth&rsquo;s surface for up to three years.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Sulphur Dioxide and Pollution:</strong><br />
<ul style="list-style-type: circle;">
<li>SO<sub>2</sub> emissions that lead to high concentrations of SO<sub>2</sub> in the air generally also lead to the formation of other sulfur oxides (SO<sub>x</sub>). SO<sub>x</sub> can react with other compounds in the atmosphere to form small particles. These particles contribute to <strong><a href="/daily-updates/daily-news-analysis/dashboard-for-monitoring-air-quality" target="_blank" rel="noopener">Particulate Matter (PM)</a> pollution.</strong></li>
<li>Small particles may penetrate deeply into the lungs and in sufficient quantities can contribute to health problems.</li>
</ul>
</li>
<li><strong>Sulphur Dioxide and Acid Rain:</strong><br />
<ul style="list-style-type: circle;">
<li>Acid rain results <strong>when sulphur dioxide (SO<sub>2</sub>) and nitrogen oxides (NO<sub>X</sub>) are emitted into the atmosphere</strong> and transported by wind and air currents.</li>
<li>The <strong>SO<sub>2</sub> and NO<sub>X</sub> react with water, oxygen and other chemicals</strong> to form sulfuric and nitric acids. These then mix with water and other materials before falling to the ground.</li>
</ul>
</li>
</ul>
<p><a href="https://www.downtoearth.org.in/news/natural-disasters/sulphur-dioxide-from-caribbean-volcano-reaches-india-wmo-confirms-76547#:~:text=The%20sulphur%20dioxide%20(SO2)%20emissions,can%20come%20down%20with%20rainfall." target="_blank" rel="noopener"><strong>Source: DTE</strong></a></p>',
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	(int) 15 => object(Cake\ORM\Entity) {

		'article_id' => (int) 8109,
		'category_id' => (int) 21,
		'title' => 'Red Sea',
		'description' => '<h3>Why in News</h3>
<p>An <strong>Iranian freighter was hit by Israel in the Red Sea</strong> in retaliation for past Iranian strikes on its vessels. The blast struck the <strong>Iranian commercial vessel MV Saviz</strong> off the coast of Djibouti.</p>
<ul style="list-style-type: square;">
<li>The attack came as Iranian officials gathered in Vienna to <strong>negotiate the restoration of a 2015 deal <a href="/daily-updates/daily-news-analysis/us-reimposes-sanctions-on-iran" target="_blank" rel="noopener">Joint Comprehensive Plan of Action (JCPOA)</a> that was designed to curb Iran&rsquo;s nuclear activities.</strong></li>
</ul>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>Red Sea:</strong><br />
<ul style="list-style-type: circle;">
<li><strong>Location:</strong><br />
<ul style="list-style-type: disc;">
<li>The Red Sea is a <strong>semi-enclosed tropical basin</strong>, bounded by northeastern Africa, to the west, and the <a href="/daily-updates/daily-news-analysis/operation-sankalp" target="_blank" rel="noopener"><strong>Arabian peninsula</strong></a>, to the east.</li>
<li>The <strong>elongated and narrow-shaped basin</strong> extends between the <a href="/daily-updates/daily-news-analysis/increase-in-frequency-of-medicanes" target="_blank" rel="noopener"><strong>Mediterranean Sea</strong></a>, to the north-west, and the Indian Ocean, to the south-east.</li>
<li>At the northern end, it separates into the <strong>Gulf of Aqaba and the Gulf of Suez</strong>, which is connected to the Mediterranean Sea via the <strong>Suez Canal.</strong></li>
<li>At the southern end, it is connected to the <strong>Gulf of Aden</strong>, and the outer Indian Ocean, via the Strait of<strong> Bab-el-Mandeb.</strong></li>
<li>It is surrounded by <a href="/to-the-points/paper3/desertification-1" target="_blank" rel="noopener"><strong>desert or semi-desert areas</strong></a>, with no major freshwater inflow.</li>
</ul>
</li>
<li><strong>Formation:</strong><br />
<ul style="list-style-type: disc;">
<li>The Red sea acquired its present shape over the <strong>past 4 to 5 million years</strong>, by slow <strong>seafloor spreading</strong>, a fact that makes it a geologically recent opening and one of the <strong>youngest oceanic zones on Earth.</strong></li>
<li>Today, the basin continues to widen at a rate of 1-2 cm per year</li>
</ul>
</li>
<li><strong>Biodiversity:</strong> <br />
<ul style="list-style-type: disc;">
<li>The unique habitats of the Red sea support a wide range of marine life, including <a href="/daily-updates/daily-news-analysis/world-turtle-day" target="_blank" rel="noopener"><strong>sea turtles</strong></a>, <a href="/daily-updates/daily-news-analysis/world-dugong-day-2020" target="_blank" rel="noopener"><strong>dugongs</strong></a>, <a href="/daily-updates/daily-news-analysis/gangetic-river-dolphin" target="_blank" rel="noopener"><strong>dolphins</strong></a> and many endemic fish species.</li>
<li><a href="/daily-updates/daily-news-analysis/significance-of-dead-coral-reef" target="_blank" rel="noopener"><strong>Coral reefs</strong></a> mainly extend along the northern and central coasts, and decrease in abundance towards the southern region, as coastal waters become more turbid.</li>
</ul>
</li>
<li><strong>The Reason why it is called Red Sea:</strong><br />
<ul style="list-style-type: disc;">
<li>There are various theories as to how the name came about, with the most popular being a reference to the <strong>seasonal blooms of Trichodesmium erythraeum (a red-colored algae)</strong> near the water&rsquo;s surface.</li>
<li>Other scholars believe it is linked to the way Asiatic languages often use colors to refer to cardinal directions, with<strong> &ldquo;red&rdquo; referring to &ldquo;south&rdquo; just as the Black Sea may be referring to the north.</strong></li>
</ul>
</li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1617945264_Image1.jpg" target="_blank" rel="noopener"><strong><img class="content-img" src="http://www.drishtiias.com/images/uploads/1617945264_Image1.jpg" style="display: block; margin-left: auto; margin-right: auto;" caption="false" width="426" height="637" /></strong></a></p>
<div class="border-bg">
<p><strong>Joint Comprehensive Plan of Action</strong></p>
<ul style="list-style-type: square;">
<li>In 2015, <strong>Iran with the P5+1 group of world powers - the US, UK, France, China, Russia, and Germany</strong> agreed on a long-term deal on its nuclear programme.</li>
<li>The deal was named as<strong> Joint Comprehensive Plan of Action (JCPOA)</strong> and in common parlance as Iran Nuclear Deal.</li>
<li>The deal came after years of tension over Iran's alleged efforts to develop nuclear weapons.</li>
<li>Iran insisted that its nuclear programme was entirely peaceful, but the international community did not believe that.</li>
<li>Under the JCPOA,<strong> Iran agreed to limit its nuclear activities</strong> by stopping uranium enrichment and allowing the international agencies to inspect its nuclear facilities in return for the lifting of economic sanctions.</li>
<li>However, in May 2018, the USA pulled out of the JCPOA and threatened to impose sanctions on Iran and on nations doing a significant amount of trade with Iran.</li>
</ul>
</div>
<p><a href="https://www.thehindu.com/todays-paper/tp-international/iranian-ship-attacked-in-red-sea-report-says-it-was-israeli-payback/article34268244.ece" target="_blank" rel="noopener"><strong>Source:TH</strong></a></p>',
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	(int) 16 => object(Cake\ORM\Entity) {

		'article_id' => (int) 7922,
		'category_id' => (int) 21,
		'title' => 'Sangay Volcano: Ecuador',
		'description' => '<h3>Why in News</h3>
<p>Recently, Ecuador&rsquo;s <strong>Sangay <a href="/daily-updates/daily-news-analysis/eruption-on-mount-etna" target="_blank" rel="noopener">volcano</a></strong> erupted.</p>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>About Sangay Volcano:<a href="http://www.drishtiias.com/images/uploads/1615619648_image2.jpg" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1615619648_image2.jpg" style="float: right;" width="300" caption="false" /></a></strong><br />
<ul style="list-style-type: circle;">
<li>Sangay volcano is one of the <strong>highest active volcanoes in the world</strong> and one of <strong>Ecuador's most active ones.</strong></li>
<li>Sangay is the southernmost <strong>stratovolcano</strong> (a volcano built up of <strong>alternate layers of lava and ash</strong>) in the northern volcanic zone of the Andes. It is 5230 m high.<br />
<ul style="list-style-type: disc;">
<li>The Andes is the <strong>longest above water mountain range in the world</strong> and boasts some of the highest peaks.</li>
<li><strong>Sangay National Park</strong> is located in the central part of Ecuador on the Andes mountains' eastern side. It is a <a href="/to-the-points/paper1/world-heritage-sites-in-india" target="_blank" rel="noopener"><strong>world heritage site</strong></a>.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Eruptions:</strong><br />
<ul style="list-style-type: circle;">
<li>The <strong>earliest</strong> report of a historical eruption was in <strong>1628</strong>. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. Sangay <strong>has had frequent eruptions in historic times</strong>, mostly of <strong>strombolian type.</strong></li>
</ul>
</li>
<li><strong>Other Major Volcanoes of Ecuador:</strong> <br />
<ul style="list-style-type: circle;">
<li>Ecuador, part of the <a href="/to-the-points/paper1/pacific-ring-of-fire" target="_blank" rel="noopener"><strong>Pacific Rim&rsquo;s &ldquo;Ring of Fire&rdquo;</strong></a> region, has eight volcanoes such as <strong>Cotopaxi</strong> (5,897m), <strong>Cayambe</strong> (5,790m), <strong>Pichincha</strong> (4,784m) etc. in its territory.</li>
</ul>
</li>
</ul>
<div class="border-bg">
<p><strong>Volcanic Eruptions</strong></p>
<ul style="list-style-type: square;">
<li><strong>About:</strong><br />
<ul style="list-style-type: circle;">
<li>Volcanic eruptions happen when <strong>lava and gas are discharged from a volcanic vent.</strong></li>
<li>The most common consequences of this are population movements as large numbers of people are often forced to flee the moving lava flow.</li>
</ul>
</li>
<li><strong>Types:</strong> Volcanic activity and volcanic areas are commonly divided into <strong>six major types:</strong><br />
<ul style="list-style-type: circle;">
<li><strong>Icelandic:</strong> <br />
<ul style="list-style-type: disc;">
<li>It is characterized by <strong>effusions of molten basaltic lava</strong> that flow from long, parallel fissures. Such outpourings <strong>often build lava plateaus.</strong></li>
</ul>
</li>
<li><strong>Hawaiian:</strong> <br />
<ul style="list-style-type: disc;">
<li>It is <strong>similar to the Icelandic variety.</strong> In this case, however, fluid lava flows from a volcano&rsquo;s summit and <strong>radial fissures</strong> to form shield volcanoes, which are quite large and <strong>have gentle slopes.</strong></li>
</ul>
</li>
<li><strong>Strombolian:</strong> <br />
<ul style="list-style-type: disc;">
<li>These involve <strong>moderate bursts of expanding gases</strong> that eject clots of incandescent lava in cyclical or nearly <strong>continuous small eruptions.</strong></li>
<li>Because of such small frequent outbursts, <strong>Stromboli volcano</strong>, located on Stromboli Island off the northeast coast of <strong>Italy</strong>, has been called the <strong>&ldquo;lighthouse of the Mediterranean.&rdquo;</strong></li>
</ul>
</li>
<li><strong>Vulcanian:</strong> <br />
<ul style="list-style-type: disc;">
<li>It is named for <strong>Vulcano Island</strong> near Stromboli, generally involving <strong>moderate explosions</strong> <strong>of gas laden with volcanic ash.</strong> This mixture forms dark, turbulent eruption clouds that rapidly ascend and expand in convoluted shapes.</li>
</ul>
</li>
<li><strong>Pelean:</strong> <br />
<ul style="list-style-type: disc;">
<li>It is associated with explosive outbursts that generate <strong>pyroclastic flows</strong>, dense mixtures of <strong>hot volcanic fragments and gas.</strong></li>
<li>The <strong>fluidized slurries</strong> produced by these eruptions are heavier than air but are of low viscosity and pour down valleys and slopes at great velocities. As a result, they are <strong>extremely destructive.</strong></li>
</ul>
</li>
<li><strong>Plinian:</strong> <br />
<ul style="list-style-type: disc;">
<li>This type is an <strong>intensely violent kind of volcanic eruption.</strong> In this type of eruption, gases boiling out of gas-rich magma generate enormous and nearly continuous jetting blasts that core out the magma conduit and rip it apart.</li>
<li>The uprushing gases and volcanic fragments <strong>resemble a gigantic</strong> <strong>rocket blast directed vertically upward.</strong> Plinian <strong>eruption clouds can rise into the stratosphere</strong> and are sometimes continuously produced for several hours.</li>
<li><strong>Lightning strikes</strong> caused by a buildup of static electricity are common close to Plinian ash clouds, adding one more element of terror to the eruption.</li>
</ul>
</li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1615620904_image3.jpg" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1615620904_image3.jpg" width="750" caption="false" style="display: block; margin-left: auto; margin-right: auto;" /></a></p>
</div>
<p><a href="https://indianexpress.com/article/world/ecuadors-sangay-volcano-erupts-ash-8-kilometers-7225406/" target="_blank" rel="noopener"><strong>Source:IE</strong></a></p>',
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	(int) 17 => object(Cake\ORM\Entity) {

		'article_id' => (int) 7745,
		'category_id' => (int) 21,
		'title' => 'Declining Rainfall in Cherrapunji',
		'description' => '<h3>Why in News</h3>
<p>A recent study that looked at the <strong>rainfall pattern in the past 119 years</strong> found a <strong>decreasing trend at Cherrapunji (Meghalaya) and nearby areas.</strong></p>
<ul style="list-style-type: square;">
<li>The village of <strong>Mawsynram in East Khasi Hills district of Meghalaya</strong> has beaten Cherrapunji to become the <strong>wettest place in the world.</strong> Mawsynram receives over 10,000 millimetres of rain in a year.</li>
<li>Mawsynram is located around <strong>81 km by road from Cherrapunji</strong> however the straight line distance between the two is <strong>15.2 km.</strong></li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1613980587_image1.png" target="_blank" rel="noopener"><strong><img class="content-img" src="http://www.drishtiias.com/images/uploads/1613980587_image1.png" style="display: block; margin-left: auto; margin-right: auto;" width="400" caption="false" /></strong></a></p>
<h3>Key Points</h3>
<ul style="list-style-type: square;">
<li><strong>Reduction in Rainfall:</strong>
<ul style="list-style-type: circle;">
<li>The <strong>annual mean rainfall</strong> for the period <strong>1973&ndash;2019</strong> showed <strong>decreasing trends</strong> of about <strong>0.42 mm per decade.</strong>
<ul style="list-style-type: disc;">
<li>It was statistically significant along seven stations <strong>(Agartala, Cherrapunji, Guwahati, Kailashahar, Pasighat, Shillong and Silchar).</strong></li>
</ul>
</li>
</ul>
</li>
<li><strong>Reasons:</strong><br />
<ul style="list-style-type: circle;">
<li><strong>Rising Temperature:</strong><br />
<ul style="list-style-type: disc;">
<li>The <strong>changes in the Indian Ocean temperature</strong> have a <strong>huge effect</strong> on the rainfall in the region.<br />
<ul style="list-style-type: disc;">
<li>Increasing sea surface temperatures in the tropical Indian Ocean region was pointed out by the <a href="/daily-updates/daily-news-analysis/assessment-of-climate-change-over-the-indian-region-moes" target="_blank" rel="noopener"><strong>first climate change assessment report</strong></a> published by the Union Ministry of Earth Sciences in June 2020.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Increased Human Activities:</strong><br />
<ul style="list-style-type: disc;">
<li>The satellite data showed that there was a <strong>reduction in the vegetation area</strong> in northeast India in the past two decades, implying that human influence also plays an important role in the changing rainfall patterns.<br />
<ul style="list-style-type: disc;">
<li>The traditional way of cultivation known as <a href="/daily-updates/daily-news-analysis/niti-aayog-report-on-shifting-cultivation" target="_blank" rel="noopener"><strong>Jhum cultivation or shifting cultivation</strong></a> is now decreased and being replaced by other methods.</li>
<li>There is sizable <a href="/daily-updates/daily-news-analysis/deforestation-rate-declined"><strong>deforestation</strong></a> in the region. The study saw the <strong>decrease in vegetation cover and increase in the areas of cropland</strong> mainly from the year 2006 onwards.</li>
<li>The analysis showed <strong>reductions in vegetation</strong> with <strong>104.5 sqkm lost per year.</strong></li>
<li>On the other hand, there were <strong>significant increases in cropland</strong> (182.1 sqkm per year) and <strong>urban and built-up lands</strong> (0.3 sqkm per year) during the period 2001&ndash;2018.</li>
</ul>
</li>
</ul>
</li>
</ul>
</li>
<li><strong>Significance of Studying the North-East Region:</strong><br />
<ul style="list-style-type: circle;">
<li>Since north-east India is mostly hilly and is an extension of the Indo-Gangetic Plains, the <strong>region is highly sensitive to changes</strong> in regional and global climate.</li>
<li>It has to be noted that the <strong>first signs of the effect of <a href="/daily-updates/daily-news-editorials/climate-change-and-development-in-india" target="_blank" rel="noopener">climate change</a></strong> will be evident for the extreme cases such as the rainfall at Cherrapunji.</li>
<li>North-east India has the <strong>highest vegetation cover</strong> in India and includes <strong>18 biodiversity hotspots of the world</strong>, indicating the importance of the region in terms of its greenery and <strong>climate-change sensitivity.</strong></li>
</ul>
</li>
</ul>
<div class="border-bg">
<p><strong>Reason for High Rainfall in Cherrapunji and Mawsynram</strong></p>
<ul style="list-style-type: square;">
<li><strong>Cherrapunji (elevation 1313 m)</strong> and <strong>Mawsynram (elevation 1401.5 m)</strong> are located on the southern slopes of the east Khasi Hills in Meghalaya. <br />
<ul style="list-style-type: circle;">
<li>Meghalaya is a mountainous state with <strong>numerous valleys and highland plateaus.</strong></li>
<li><strong>Elevation</strong> in the plateau region ranges between <strong>150 m</strong> to <strong>1,961 m ,</strong> with the central part comprising the Khasi Hills with the highest elevations.</li>
</ul>
</li>
<li>The rainfall in Cherrapunji-Mawsynram is <strong>caused by the orography favouring a monsoon wind regime.</strong></li>
<li>The northward moving moist winds from the Bay of Bengal passing over the plains of Bangladesh are <strong>forced to converge in the narrow valleys of the Khasi Hills</strong> with orography providing forced ascent that causes condensation, formation of clouds resulting in rain on the windward side of the slope.</li>
</ul>
<p><strong>Shifting Cultivation</strong></p>
<ul style="list-style-type: square;">
<li>Shifting cultivation, locally called 'Jhum', is a widely practiced system of crop cultivation among the indigenous communities of North-east India. The practice, also known as <strong>slash-and-burn agriculture</strong>, is when farmers clear land by slashing vegetation and burning forests and woodlands to create clear land for agricultural purposes.</li>
<li>This provides a <strong>very easy and very fast method</strong> of the preparation of the land for agriculture.</li>
<li>The bush and the weeds can be removed easily. The <strong>burning of waste materials provides needed nutrients for the cultivation.</strong></li>
<li>It <strong>gives</strong> a family its <strong>food, fodder, fuel, livelihood</strong> and is closely linked to their identity.</li>
<li>Because of cutting of forests and trees, this practice <strong>leads to soil erosion and may also affect the course of rivers.</strong></li>
</ul>
</div>
<p><a href="https://www.thehindu.com/sci-tech/science/wettest-place-on-earth-sees-decreasing-trend-in-rainfall/article33889697.ece#:~:text=The%20quiet%2C%20sleepy%2C%20yet%20mesmerising,to%20The%20Hindu%20subscribers%20only." target="_blank" rel="noopener"><strong>Source:TH</strong></a></p>',
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	(int) 18 => object(Cake\ORM\Entity) {

		'article_id' => (int) 7743,
		'category_id' => (int) 26,
		'title' => 'Deglaciation and Threats',
		'description' => '<h3>Deglaciation </h3>
<ul style="list-style-type: square;">
<li>Glaciers, ice caps and continental ice sheets <strong>cover some 10% of the earth&rsquo;s land surface</strong> at the present time, whereas during the ice ages, they covered about three times this amount <br />
<ul style="list-style-type: circle;">
<li>The present ice cover corresponds to about three-quarter of the world&rsquo;s total freshwater resources. </li>
</ul>
</li>
<li>The gradual melting away of a glacier from the surface of a landmass is known as <strong>Deglaciation.</strong><br />
<ul style="list-style-type: circle;">
<li>The processes that remove snow, ice, and moraine from a glacier or ice sheet are called <strong>Ablation.</strong> <br />
<ul style="list-style-type: disc;">
<li>It includes melting, evaporation, erosion, and calving.</li>
</ul>
</li>
</ul>
</li>
<li>The process of deglaciation, that intensified in the 20th century, is leaving our planet iceless. </li>
</ul>
<h3>Causes of Deglaciation</h3>
<ul style="list-style-type: square;">
<li><strong>Global warming:</strong> The atmospheric concentration of carbon dioxide, methane and other greenhouse gases (GHGs) produced by <strong>industry, transport, deforestation and burning fossil fuels,</strong> amongst other human activities, <strong>warm the planet and cause glaciers to melt.</strong></li>
<li><strong>Ocean warming:</strong> Oceans absorb 90% of the Earth's warmth, and this affects the melting of marine glaciers, which are mostly located near the poles.</li>
<li><strong>Rapid industrialisation:</strong> Since the early 1900s, many glaciers around the world have been rapidly melting, <strong>specifically, since the industrial revolution,</strong> carbon dioxide and other<strong> greenhouse gas emissions have raised temperatures,</strong> even <strong>higher in the poles,</strong> and as a result, glaciers are rapidly melting, calving off into the sea and retreating on land.</li>
</ul>
<h3>Impacts of Deglaciation</h3>
<ul style="list-style-type: square;">
<li><strong>Raised sea level:</strong> The melting glaciers have played the major role in<strong> raising average global sea level between four and eight inches</strong> (10 and 20 centimeters) in the past hundred years, according to the <a href="/daily-updates/daily-news-analysis/special-report-on-climate-change-ipcc" target="_blank" rel="noopener"><strong>Intergovernmental Panel on Climate Change (IPCC).</strong></a><br />
<ul style="list-style-type: circle;">
<li>Rising sea levels increase coastal erosion and elevates storm surge as warming air and ocean temperatures create more frequent and intense coastal storms like hurricanes and typhoons.</li>
</ul>
</li>
<li><strong>On mountain glaciers:</strong> The famed snows of <strong>Kilimanjaro</strong> have melted more than 80% since 1912. <br />
<ul style="list-style-type: circle;">
<li><strong>Glaciers in the Garhwal region</strong> of the Himalayas are retreating so fast that researchers believe that most central and eastern Himalayan glaciers could virtually disappear by 2035. </li>
</ul>
</li>
<li><strong>In the Northern Hemisphere:</strong> Spring freshwater ice breakup in the Northern Hemisphere now<strong> occurs nine days earlier</strong> than it did 150 years ago, and <strong>autumn freeze-up ten days later. </strong><br />
<ul style="list-style-type: circle;">
<li><strong>Arctic sea</strong> ice has thinned significantly over the past half century, and its extent has declined by about 10% in the past 30 years. </li>
<li>The <strong>Greenland</strong> ice sheet is disappearing four times faster than in 2003 and already contributes 20% of current sea level rise.</li>
</ul>
</li>
<li><strong>Melting of Thwaites Glacier:</strong> Also called <a href="/daily-updates/daily-news-analysis/melting-of-thwaites-glacier" target="_blank" rel="noopener"><strong>Doomsday Glacier</strong></a>, it is a 120 km wide, fast-moving glacier located in <strong>Antarctica.</strong><br />
<ul style="list-style-type: circle;">
<li>Because of its size (1.9 lakh square km), it contains enough water to raise the world sea level by more than half a metre.</li>
<li>Studies have detected the <strong>presence of warm water</strong> at a vital point beneath the Thwaites glacier as the cause of its melting.</li>
<li>Its <strong>melting already contributes 4% to global sea-level rise each year.</strong> It is estimated that it would collapse into the sea in 200-900 years.<br />
<ul style="list-style-type: disc;">
<li>Studies have found the amount of ice flowing out of it has nearly doubled over the past 30 years.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Disappearance of species:</strong> Glaciers are the natural habitat of a number of animals, both terrestrial and aquatic, if the melting continues at the same rate, a number of species will become extinct.<br />
<ul style="list-style-type: circle;">
<li>It will also disturb the balance of the food chain.</li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1613974001_image1.jpg" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1613974001_image1.jpg" style="display: block; margin-left: auto; margin-right: auto;" width="550" caption="false" /></a></p>
<h3>The Himalayan Glaciers</h3>
<p><strong>About</strong></p>
<ul style="list-style-type: square;">
<li>Himalayan glaciers form the largest body of ice outside the polar caps and are the source of water for the innumerable rivers that flow across the Indo-Gangetic plains. <br />
<ul style="list-style-type: circle;">
<li>Himalayan glaciers are also known as the Third Pole. </li>
</ul>
</li>
<li>Himalayan glacial snowfields store about 12,000 km3 of freshwater. </li>
<li>15,000 Himalayan glaciers form a unique reservoir which supports perennial rivers such as the Indus, Ganga and Brahmaputra which, in turn, are the lifeline of millions of people in South Asian countries (Pakistan, Nepal, Bhutan, India and Bangladesh). </li>
<li>The Gangetic basin alone is home to 500 million people, about 10% of the total human population in the region.</li>
</ul>
<p><strong>The Receding Glaciers</strong></p>
<ul style="list-style-type: square;">
<li><strong>Rate of receding:</strong> Glaciers in the Himalaya are receding faster than in any other part of the world. <br />
<ul style="list-style-type: circle;">
<li>The glaciers have been losing the equivalent of more than a vertical foot and half of ice each year since 2000; double the amount of melting that took place from 1975 to 2000.</li>
<li>According to the statistics in the last 25 years approximate 400 crore tons of ice being melted in the Himalayan glaciers.</li>
<li>The 30.2 km long <a href="/daily-updates/daily-news-analysis/concentration-of-black-carbon-on-gangotri-glacier" target="_blank" rel="noopener"><strong>Gangotri Glacier</strong> </a>has been receding alarmingly in recent years.</li>
</ul>
</li>
<li><strong>Cause of receding:</strong> The receding and thinning of Himalayan glaciers can be attributed primarily to global warming due to increase in anthropogenic emission of greenhouse gases. <br />
<ul style="list-style-type: circle;">
<li>The relatively high population density near these glaciers and consequent deforestation and land-use changes have also adversely affected these glaciers. </li>
</ul>
</li>
<li><strong>Effect on the Hindukush region:</strong> Climate change has hastened glacial melting across the <a href="/daily-updates/daily-news-analysis/hindu-kush-himalayan-region" target="_blank" rel="noopener"><strong>Hindu Kush Himalayan (HKH) region</strong></a>, home to some of the world&rsquo;s tallest peaks, including Mount Everest.<br />
<ul style="list-style-type: circle;">
<li>The recent <a href="/daily-updates/daily-news-analysis/uttarakhand-flash-flood" target="_blank" rel="noopener"><strong>glacier collapse at Nanda Devi</strong></a> in Uttarakhand&rsquo;s Chamoli district led to a massive flood in the Dhauli Ganga river and caused large-scale devastation in the upper reaches of the ecologically fragile Himalayas.</li>
</ul>
</li>
<li><strong>Air warming over HKH:</strong> Air over HKH warmed at a rate of 0.2℃ each decade from 1951 to 2014 and at an even higher rate of 0.5℃ per decade at elevations higher than 4,000 meters, as per a report prepared by the Ministry of Earth Sciences (MoES). <br />
<ul style="list-style-type: circle;">
<li>The report projected that even with the Indian government&rsquo;s commitment to mitigate greenhouse gases by 2030, the Indian Himalayas could warm by 2.6℃&ndash;4.6℃ by 2100. </li>
<li>In the worst-case scenario, the mean surface temperature over the whole region could rise by 5.2℃ by 2100.</li>
</ul>
</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1613973937_image2.png" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1613973937_image2.png" style="display: block; margin-left: auto; margin-right: auto;" width="500" caption="false" /></a></p>',
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	(int) 19 => object(Cake\ORM\Entity) {

		'article_id' => (int) 7688,
		'category_id' => (int) 26,
		'title' => 'Glaciers',
		'description' => '<h3>About</h3>
<ul style="list-style-type: square;">
<li>A glacier is a large, <strong>perennial accumulation of crystalline ice, snow, rock, sediment,</strong> and <strong>water</strong> that originates on land and moves down slope under the influence of its own weight and gravity. They are <strong>sensitive indicators of changing climate.</strong></li>
<li>Out of total water on Earth, <strong>2.1% is in glaciers while 97.2% is in the oceans</strong> and inland seas.</li>
<li><strong>Condition of glacier formation:</strong><br />
<ul style="list-style-type: circle;">
<li><strong>Mean annual temperatures</strong> are close to the freezing point.</li>
<li><strong>Winter precipitation</strong> produces significant accumulations of snow.</li>
<li><strong>Temperatures throughout the rest of the year</strong> do not result in the complete loss of the previous winter&rsquo;s snow accumulation.</li>
</ul>
</li>
</ul>
<p><strong>Formation of Glacier</strong></p>
<ul style="list-style-type: square;">
<li>Glaciers begin forming in places where more snow piles up each year than melts. Soon after falling, the snow begins to compress, or become denser and tightly packed.<br />
<ul style="list-style-type: circle;">
<li>The process of snow compacting into glacial firn (dense, grainy ice) is called <strong>firnification</strong>.</li>
</ul>
</li>
<li>When the ice grows thick enough, about 50 meters (160 feet), the firn grains fuse into a huge mass of solid ice. The glacier begins to move under its own weight.<br />
<ul style="list-style-type: circle;">
<li>Different parts of a glacier move at different speeds. The flowing ice in the middle of the glacier moves faster than the base.</li>
</ul>
</li>
</ul>
<p><strong>Geographical Location</strong></p>
<ul style="list-style-type: square;">
<li><strong>91%</strong> of the Glaciers are in <strong>Antarctica</strong> and <strong>8%</strong> are in <strong>Greenland.</strong> They occupy about 10% of the world's total land area.</li>
</ul>
<p><a href="http://www.drishtiias.com/images/uploads/1613373504_image1.png" target="_blank" rel="noopener"><img class="content-img" src="http://www.drishtiias.com/images/uploads/1613373504_image1.png" width="600" caption="false" style="display: block; margin-left: auto; margin-right: auto;" /></a></p>
<p><strong>Significance:</strong></p>
<ul style="list-style-type: square;">
<li><strong>Glaciers as Reservoirs:</strong> About <strong>three-quarters</strong> of Earth's freshwater is stored in glaciers. Therefore, glacier ice is the <strong>second largest reservoir of water</strong> on Earth and the <strong>largest reservoir of freshwater</strong> on Earth.<br />
<ul style="list-style-type: circle;">
<li>The cold runoff from glaciers also affects downstream water temperatures.</li>
</ul>
</li>
<li><strong>Glaciers feeding Rivers:</strong> The <strong>Gangotri Glacier</strong>, one of the largest glaciers in the Himalayan Mountains, is <strong>the source of the Ganga River</strong>. <br />
<ul style="list-style-type: circle;">
<li>The Ganges is the most important source of freshwater and electricity in India and Bangladesh.</li>
</ul>
</li>
<li><strong>Glaciers for Aquatic Life:</strong> Many <strong>aquatic species in mountainous environments</strong> require cold water temperatures to survive which is provided by Glaciers. <br />
<ul style="list-style-type: circle;">
<li>Some <strong>aquatic insects</strong> are <strong>especially sensitive to stream temperature</strong> and cannot survive without the cooling effects of glacial meltwater.</li>
<li>Such changes in stream habitat may also <strong>adversely impact native trout</strong> and other <strong>keystone salmon species.</strong></li>
</ul>
</li>
<li><strong>Glaciers for People:</strong> Glaciers provide people with many useful resources. Glacial till <strong>provides fertile soil for growing crops</strong>.<br />
<ul style="list-style-type: circle;">
<li>Deposits of sand and gravel are used to make <strong>concrete and asphalt</strong>.</li>
</ul>
</li>
</ul>
<h3>Classification of Glaciers</h3>
<ul style="list-style-type: square;">
<li>Glaciers can be classified according to their: <br />
<ul style="list-style-type: circle;">
<li><strong>Size</strong> (i.e. ice sheet, ice cap, valley glacier, cirque glacier)</li>
<li><strong>Thermal regime</strong> (polar vs. temperate).</li>
</ul>
</li>
</ul>
<p><strong>Size Based</strong></p>
<ul style="list-style-type: square;">
<li><strong>Ice Cap:</strong> An ice cap is a dome-shaped glacier mass flowing in all directions, such as the ice cap on Ellesmere Island in the Canadian Arctic. <br />
<ul style="list-style-type: circle;">
<li>There is still some <strong>uncertainty about the full volume of glaciers and ice caps</strong> on Earth, but if all of them were to melt, <strong>global sea level would rise approximately 70 meters</strong> (approximately 230 feet), flooding every coastal city on the planet.</li>
</ul>
</li>
<li><strong>Valley Glaciers:</strong> Also called <strong>Alpine Glaciers</strong> or <strong>Mountain Glaciers</strong>, they form on mountainsides and move downward through valleys. <br />
<ul style="list-style-type: circle;">
<li>They are <strong>found in high mountains</strong> <strong>of every continent except Australia</strong> (although there are many in New Zealand). <br />
<ul style="list-style-type: disc;">
<li>Example: The <strong>Gorner Glacier in Switzerland</strong> and the <strong>Furtwangler Glacier in Tanzania</strong>.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Ice Sheets:</strong> Unlike valley glaciers, ice sheets are not limited to mountainous areas. They form broad domes and spread out from their centers in all directions. <br />
<ul style="list-style-type: circle;">
<li>As ice sheets spread, they cover everything around them with a thick blanket of ice, including valleys, plains, and even entire mountains.</li>
<li>The largest ice sheets, called <strong>continental glaciers</strong>, spread over vast areas. <br />
<ul style="list-style-type: disc;">
<li>Continental glaciers <strong>cover most of Antarctica and the island of Greenland</strong>.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Cirque glaciers:</strong> They are short and wide, are confined to cirques, or amphitheatres, cut in the mountain landscape.</li>
</ul>
<p><strong>Thermal Regime based:</strong></p>
<ul style="list-style-type: square;">
<li><strong>Polar Glacier:</strong> A polar glacier is defined as one that is below the freezing temperature throughout its mass for the entire year.<br />
<ul style="list-style-type: circle;">
<li>A subpolar glacier contains ice below the freezing temperature, except for surface melting in the summer and a basal layer of temperate ice.</li>
</ul>
</li>
<li><strong>Temperate Glacier:</strong> A temperate glacier is the one that&rsquo;s <strong>essentially at the melting point</strong>, so liquid water coexists with glacier ice. <br />
<ul style="list-style-type: circle;">
<li>They are found in North America, South America, Europe, Africa, and <strong>Asia</strong> and <strong>New Zealand.</strong> <br />
<ul style="list-style-type: disc;">
<li>Some of the <strong>Antarctic glaciers</strong> and <strong>Greenland&rsquo;s southern outlet glaciers</strong> are temperate.</li>
</ul>
</li>
</ul>
</li>
</ul>
<h3>Landforms Formed</h3>
<p><strong>Erosional Landforms</strong><br /><strong></strong></p>
<ul style="list-style-type: square;">
<li><strong>Glacial Valleys/Troughs:</strong> These valleys are <strong>trough-like and U-shaped</strong> with broad floors and relatively smooth, and steep sides. <br />
<ul style="list-style-type: circle;">
<li>The valleys may contain littered debris or debris shaped as <strong>moraines</strong> with swampy appearance.</li>
<li>Very deep glacial troughs filled with sea water and making up shorelines (in high latitudes) are called <strong>fjords/fiords.</strong></li>
</ul>
</li>
<li><strong>Cirques:</strong> Often are found at the heads of glacial valleys, these are the most common of landforms in glaciated mountains. <br />
<ul style="list-style-type: circle;">
<li>They are <strong>deep, long and wide troughs</strong> or basins with very steep concave to vertically dropping high walls at its head as well as sides.</li>
<li>A lake of water can be seen quite often within the cirques after the glacier disappears. Such lakes are called <strong>cirque lakes or tarn lakes.</strong></li>
</ul>
</li>
<li><strong>Horns and Serrated:</strong> Ridges Horns form through headward erosion of the cirque walls. <br />
<ul style="list-style-type: circle;">
<li>If three or more radiating glaciers cut headward until their cirques meet, high, sharp pointed and steep sided peaks called horns form.</li>
</ul>
</li>
</ul>
<p><strong>Depositional Landforms:</strong></p>
<ul style="list-style-type: square;">
<li><strong>Glacial Till:</strong> The unassorted coarse and fine debris dropped by the melting glaciers is called glacial till. <br />
<ul style="list-style-type: circle;">
<li>Some amount of rock debris small enough to be carried by such melt-water streams is washed down and deposited. <br />
<ul style="list-style-type: disc;">
<li>Such glaciofluvial deposits are called <strong>outwash deposits</strong>.</li>
<li>The outwash deposits are roughly stratified and assorted.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Moraines:</strong> They are <strong>long ridges of deposits of glacial till.</strong> <br />
<ul style="list-style-type: circle;">
<li><strong>Terminal moraines</strong> are long ridges of debris deposited at the end (toe) of the glaciers.</li>
<li>Lateral moraines form along the sides parallel to the glacial valleys.</li>
<li>Many valley glaciers retreating rapidly leave an irregular sheet of till over their valley floors called <strong>ground moraines.</strong></li>
<li>The moraine in the centre of the glacial valley flanked by lateral moraines is called <strong>medial moraine.</strong> <br />
<ul style="list-style-type: disc;">
<li>They are imperfectly formed as compared to lateral moraines. Sometimes medial moraines are indistinguishable from ground moraines.</li>
</ul>
</li>
</ul>
</li>
<li><strong>Eskers:</strong> These are ridges made of sands and gravels, deposited by glacial meltwater flowing through tunnels within and underneath glaciers, or through meltwater channels on top of glaciers.<br />
<ul style="list-style-type: circle;">
<li>Over time, the channel or tunnel gets filled up with sediments. As the ice retreats, the sediments are left behind as a ridge in the landscape.</li>
</ul>
</li>
<li><strong>Drumlins:</strong> They are <strong>smooth oval shaped ridge-like features</strong> composed mainly of glacial till with some masses of gravel and sand. <br />
<ul style="list-style-type: circle;">
<li>The long axes of drumlins are parallel to the direction of ice movement.</li>
<li>They may measure up to 1 km in length and 30 m or so in height.</li>
<li>The drumlin end facing the glacier is called the stoss end and is blunter and steeper than the other end called tail.&nbsp;</li>
</ul>
</li>
</ul>
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