Climate Change Disrupts Global Water Cycle: Rising Extremes in Floods, Droughts, and Precipitation

(Source – Indian Express, Section – Explained – Page No. – 23)

Analysis of the news:

Climate Change and the Water Cycle

• Climate change is profoundly disrupting the Earth’s water cycle, leading to intensified extreme weather events such as floods, droughts, and storms.
• The 2024 Global Water Monitor Report, compiled by an international research team, sheds light on these disruptions and their widespread impacts.

Understanding the Water Cycle

• The water cycle involves the continuous movement of water in its solid, liquid, and gaseous states across the Earth’s surface, atmosphere, and subsurface.
• Powered by the Sun, processes like evaporation, transpiration, condensation, and precipitation regulate water availability and weather patterns essential for life on Earth.

Impact of Climate Change on the Water Cycle

1. Intensified Evaporation and Precipitation:
   1. Rising global temperatures cause increased evaporation, leading to more moisture in the atmosphere.
   1. Warmer air holds 7% more moisture for every 1°C rise, resulting in heavier and more frequent precipitation.
2. Droughts and Dry Soil:
   1. Higher evaporation rates dry out soils, making them less absorbent when rain does fall.
   1. This perpetuates a cycle of drought and surface water runoff, limiting soil moisture retention.
3. Projected Trends:
   1. Global temperatures are expected to rise by 2.6–3.1°C by the century’s end, exacerbating water cycle disruptions.
   1. The IPCC predicts long-term changes, including more severe droughts and extreme rainfall.

Key Findings of the 2024 Global Water Monitor Report

1. Disasters and Economic Impact:
   1. In 2024, water-related disasters caused over 8,700 deaths, displaced 40 million people, and resulted in $550 billion in economic losses.
2. Increased Extremes:
   1. Record-dry months occurred 38% more often than the baseline period (1995-2005).
   1. Record-breaking rainfall events have surged, with daily rainfall records set 52% more frequently compared to 2000.
3. Regional Trends in Water Storage:
   1. Persistent low terrestrial water storage (TWS) values were observed in most dry regions.
   1. Exceptions included increases in TWS in parts of Africa.
4. 2025 Projections:
   1. Drought conditions are expected to worsen in northern South America, southern Africa, and parts of Asia.
   1. Flood risks are likely to intensify in wetter regions such as the Sahel and Europe.

Conclusion:

• The findings highlight the urgent need for global efforts to mitigate climate change and adapt to its impacts on the water cycle.
• Reducing greenhouse gas emissions and improving water management strategies are critical to countering the escalating risks posed by these disruptions.

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