Thirst Waves | 25 Jun 2025

Source: TH

Global warming is making the air thirstier, causing higher evaporative demand that dries out land and plants—a phenomenon called thirst waves.

Thirst Waves

• About: Thirstwave, a term coined by researchers Meetpal Kukal and Mike Hobbins, refers to a period of three or more consecutive days with extreme atmospheric evaporative demand—reflecting how "thirsty" the air is for moisture.
• Causes: Thirst waves are influenced by temperature, humidity, solar radiation, and wind speed, unlike heatwaves, which are mainly driven by temperature and wind.
• Measurement: It is measured through Short-crop evapotranspiration that measures water loss from a well-watered 12-cm grass surface.
  • Rising evapotranspiration indicates higher temperatures, lower humidity, and increased wind speed and solar radiation.
• Impact: Stronger thirst waves lead to faster soil moisture loss, greater irrigation requirements, and a higher risk of crop stress and yield reduction.
• Thirstwaves & India: Studies show that evaporative demand is increasing in parts of India, including Northern India and the Western/Eastern Himalayas, driven by agricultural expansion and vegetation growth.
  • While in the past, higher humidity helped offset the impact of rising temperatures, future warming is expected to further raise evaporative demand.