How climate change is shifting the water cycle

  • 15.10.2022
  • DW

What is the water cycle?

Put simply, the water cycle — also known as the hydrological cycle — is the process by which watermoves through the Earth's land, seas and atmosphere. Water in its three natural phases, be it gas, liquid or solid, forms part of the natural cycle that continuously refreshes the supply of water that we, and every other living thing, need to survive.

Of the world's finite supply of water, around 97% is salty. The remaining 3% is fresh water which we use for things like drinking, bathing or irrigating crops. Most of that, however, is out of reach, locked away in the ice or deep underground in aquifers. Only around 1% of the world's total water supply is readily available to sustain all life on Earth.

How does the water cycle work?

The water held in lakes, rivers, oceans and seas is constantly heated by the sun. As the surface warms, liquid water evaporates and becomes vapor, escaping into the atmosphere. Wind can speed up that evaporation process. Plants also release water vapor through the pores, or stoma, of their leaves and stems, in what's known as transpiration.

How climate change is disrupting the water cycle

Recent research shows that in some parts of the world, the water cycle is speeding up in response to human-caused climate change.

Warmer temperatures are heating the lower atmosphere and increasing evaporation, adding more water vapor to the air. More water in the air means a greater chance of precipitation, often in the form of intense, unpredictable storms. Conversely, increased evaporation can also intensify dry conditions in areas prone to drought, with water escaping into the atmosphere rather than staying on the ground where it's needed.