Droughts and rains could be more extreme, due to global warming

The distortion of the water cycle, particularly its extremes (droughts and rains), will be among the consequences of climate change in the future. 

This is stated by an American research group that studied 1,056 extreme events between 2002-2021 and that published its findings in Nature on March 13.

Droughts and rains

The study claims that the total intensity of extreme events was strongly correlated with global mean temperature, rather than with the El Niño Southern Oscillation or other climate indicators, suggesting that continued global warming will cause more frequent droughts and floods, more severe, longer and/or larger.

According to a recent study, the frequency and intensity of both rainfall and droughts are increasing due to human activities that release greenhouse gases, such as burning fossil fuels.

The study's author, Matthew Rodell, was surprised by how strongly correlated global intensity was with global mean temperatures.

The findings suggest that continued global warming will lead to more severe, frequent, and longer droughts and rainstorms.

Most extreme rainfall events

The study analyzed 1,056 events between 2002 and 2021, using a new algorithm to identify where the land is much wetter or drier than usual.

The most extreme rainfall events occurred in sub-Saharan Africa, central and eastern North America, and Australia, while the most intense droughts occurred in northeastern South America, the Cerrado region of Brazil, and the American Southwest, which has led to dangerously low water levels in two of the United States' largest reservoirs, Lake Mead and Lake Powell.

"I was surprised to see how well the global intensity was correlated with global mean temperatures," said Phys quoted Matthew Rodell, study author and deputy director of Earth sciences for hydrosphere, biosphere and geophysics at the Goddard Space Flight Center from NASA.

Warmer atmosphere increases water evaporation

A study has revealed that drought events have outnumbered heavy rain events by 10%, and both types of extreme weather have had similar geographic extents and durations.

The study has also indicated that a warmer atmosphere increases water evaporation rates during dry spells and holds more water vapour, which contributes to more severe heavy rainfall events.

The authors of the study have noted that infrastructure designed to withstand once-in-a-century events, such as airports and sewage treatment plants, are increasingly being challenged as extreme weather events occur more frequently and with greater intensity.

Climate scientist Richard Seager has warned that the future may see wetter extremes become wetter and dry extremes become drier, making it necessary to rethink strategies for managing water resources and flood control.

"Weather whiplash," a severe swing between extreme drought and flooding, has become increasingly common in some regions, with ecosystems and disenfranchised communities expected to bear the brunt of the water stress.

The study suggests using floodwaters to replenish depleted aquifers and improving the health of agricultural soil as a couple of methods to improve water resiliency in a warming world.

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