Thirstwaves

GS II – GEOGRAPHY

Context

Recent studies reveal that thirstwaves—atmospheric events marked by high moisture demand—are increasing in intensity, frequency, and duration, especially during the growing season.

What Are Thirstwaves?

• • Episodes where the atmosphere draws excessive moisture from soil and vegetation, impacting agriculture and water security.

• Difference from Heatwaves:
  • Heatwaves are mainly driven by temperature and wind patterns.
  • Thirstwaves are driven by a combination of temperature, humidity, solar radiation, and wind speed.

Evaporative Demand:

• Meaning:
  • Refers to the atmosphere’s capacity to absorb water through evaporation and transpiration.
• Imbalance Scenario:
  • During droughts or moisture stress, evapotranspiration cannot meet demand, leading to depletion of soil moisture and crop stress.

Relevance to India:

• Observations indicate a rise in actual evapotranspiration across regions including the Himalayas and northern plains.

Projections suggest that future warming will likely increase potential evapotranspiration across India, with regional and seasonal variations.