Climate Change Speeds Water Cycle, Causes Extremes

Around the globe, intense weather events are increasing in frequency and severity due to increasing global temperatures. Prolonged drought, destructive wildfires, and extreme water shortages are machines that affect areas previously with more regular rainfall. Concurrently, torrential rains trigger catastrophic floods, overwhelm infrastructure, and displace people. The paradox of having both record drought and record-breaking rain is one direct effect of climate change, accelerating the natural water cycle.

The hydrological cycle—the perpetual flow of water between the Earth and its atmosphere—is being disrupted as the planet heats up. Largely powered by the combustion of fossil fuels such as coal and gas, this heating has set up a system in which wet conditions are becoming wetter, and dry conditions are getting even drier. The atmosphere, which is a huge reservoir of water vapor, is now taking in more moisture as a result of rising temperatures. The atmosphere contains 7% more water vapor for each degree Celsius increase in global temperature. This heightened process has dire effects.

Areas already suffering from dry conditions are experiencing longer and more severe droughts. With the added atmospheric need for water, water is evaporating more quickly from bodies of water, plants, and land. This loss of surface water not only adds to the drought condition but also contributes to land degradation and desertification. Areas that were once fertile are becoming barren, and the number of times severe water deficiencies occur is on the increase.

The effect of that drying can be witnessed in California, which was brought from drought extremes to all-time highs of rain in 2023. Years of water deficits were then followed by the state's usually rainy season coming unusually wet and heavily vegetative. But then dryness crept back, and that vegetation provided fuel for Los Angeles's devastating January fires. This cycle of alternating extremes—intense rainfall followed by prolonged drought—creates conditions that make wildfires more destructive and harder to control.

Whereas some regions are plagued with perpetual dryness, others are experiencing record-high rain. When the atmospheric conditions are right, the saturated atmosphere unleashes its surplus moisture in brief, intense storms. The outcome is torrential downpours that may overwhelm rivers, dams, and drainage systems in a matter of minutes, producing devastating floods. In contrast to persistent, controllable rain, these showers are brief torrents of water that fall in a short space of time, producing flash flooding and landslides.

This is happening across the globe. Nations with once-reliable seasonal rains are now experiencing unreliable weather. Areas that depend on monsoon rains to plant and harvest crops are facing delayed or unseasonable rains, crippling farmers to sustain crop yields. Infrastructure built based on previous climate conditions is now crumbling under the impact of new, unprecedented weather patterns.

Experts predict that as long as greenhouse gas emissions keep on increasing, this speeding up of the water cycle will only grow stronger. The rise in both extended droughts and heavy rainfalls underlines the importance of tackling climate change. Scientists are calling for prompt action, such as lowering fossil fuel use, investing in water-saving measures, and making infrastructure more resilient to extreme weather.

The future of water supply and climate stability hinges on how rapidly and efficiently the world acts to meet this increasing crisis. If no action is taken, communities will experience more frequent and intense droughts, exacerbating wildfires, and catastrophic floods—making life more challenging in much of the world.

Source - phys.org