How water moves through Earth
The water cycle (hydrological cycle) is the continuous movement of water through the hydrosphere, atmosphere, geosphere, and biosphere. Solar energy drives evaporation; gravity drives precipitation and runoff. No water is created or destroyed — it is endlessly recycled.
Transpiration: Plants also release water vapour through their leaves — a process called transpiration. Combined with evaporation, this is called evapotranspiration. Forests are major contributors to atmospheric moisture and rainfall patterns.
Monsoons and freshwater
🌧️ The Southwest Monsoon
India receives 70–90% of its annual rainfall during the southwest monsoon (June–September). Warm, moist air from the Indian Ocean is drawn inland by the low pressure over the Thar Desert. As this air rises over the Western Ghats and Himalayas, it cools and condenses, releasing heavy rainfall. The Brahmaputra valley and Cherrapunji in Meghalaya receive some of the highest rainfall on Earth (over 11,000 mm/year).
🏔️ Himalayan Glaciers
The Himalayas store water as ice (cryosphere) during winter and release it as meltwater in summer, feeding the Ganga, Indus, and Brahmaputra rivers. These rivers support over 500 million people. Glacier retreat due to climate change threatens this freshwater supply.
🌊 Groundwater
When rain infiltrates soil, it recharges underground aquifers. India has the world's largest groundwater extraction — over 250 billion cubic metres per year. Overextraction is causing water tables to fall in Punjab, Haryana, and Rajasthan.
How warming alters the water cycle
A warmer atmosphere holds more water vapour (about 7% more per 1°C of warming). This intensifies the water cycle — making wet regions wetter and dry regions drier. Extreme weather events become more frequent and severe.