Warming climate is making floods and droughts worse, study says

The level of Lake Mead has fallen dramatically in the space of just 20 years.

The intensity of droughts and extreme precipitation events has “sharply” increased over the past twenty years, says a study published Monday by the scientific journal Nature Water.

These are not just harsh weather events, but extreme events that lead to crop failure, infrastructure damage, and even humanitarian crises and conflict.

The big picture comes from data from a pair of satellites known as GRACE (Gravity Recovery and Climate Experiment), which were used to measure changes in climate storage. #x27;water on Earth means the sum of all water on and in the earth including groundwater, surface water, ice and snow.

It's amazing that we can now track the evolution of continental waters from space, said Park Williams, a bioclimatologist at the University of California, Los Angeles who was not involved in the study. the study.

The water is receding, creating a huge valley in California.

I have a feeling that when future generations look back and try to determine when humanity really began to understand the planet as a whole, this study will be one of those that will be highlighted. before, he added.

The researchers say the data confirms that the frequency and intensity of rainfall and droughts are increasing due to the use of fossil fuels and other human activities that release greenhouse gases.

I was surprised at how well global intensity correlated with average global temperatures, said Matthew Rodell, author of the x27;study and Deputy Director of Earth Sciences for Hydrosphere, Biosphere, and Geophysics at NASA's Goddard Space Flight Center.

The close link between these climate extremes and rising global average temperatures means that continued global warming will lead to more droughts and rainstorms that will be worse in many ways: more frequent, more severe, longer and worse.

Researchers examined 1,056 events that occurred between 2002 and 2021 using a new algorithm that identifies places where the earth is significantly wetter or drier than normal.

It shows that the most extreme rains continue to occur in sub-Saharan Africa, at least until December 2021, the date of the end of the data. Extreme rainfall also occurred in central and eastern North America between 2018 and 2021, as well as in Australia between 2011 and 2012.

Drought affected the Lagoa do Peixe (fish lagoon) in Tavares, Rio Grande do Sul state in Brazil last February.

The most intense droughts were a record drought in northeastern South America in 2015-2016; an event in the Cerrado region of Brazil that began in 2019 and is ongoing; and the current drought in the Southwestern United States, which has resulted in dangerously low water levels in two of America's largest reservoirs, Lake Mead and Lake Powell. These levels remain low despite the heavy rains this year.

Drought episodes were 10% more numerous than heavy rain episodes. Their geographic extent and duration are similar.

A warmer atmosphere increases the rate of water evaporation during periods of drought. It also contains more water vapor, which fuels heavy rainfall.

The study highlights that infrastructure such as airports and sewage treatment plants, which have been designed to withstand once-in-a-lifetime events 100 years, are increasingly in demand, as these extreme events occur more often and with greater intensity.

Looking into the future, in terms of water resource management and flood control, one would expect the wet extremes to be wetter and the extremes to be drier drier, said Richard Seager, a climatologist with Columbia University's Lamont Doherty Earth Observatory, who was not involved in the study.

Mr. Seager believes it is a mistake to think that future wet and dry extremes can be managed the same way as in the past, because everything will be amplified at both ends of the wet-dry spectrum.

Displaced Somali women wait to fill water canisters. The drought in Somalia has caused a lot of displacement of people, both inside and outside the country.

Water stress is expected to significantly affect poor and disenfranchised communities, as well as ecosystems that have been underfunded and exploited.

For example, the United Nations has warned that Somalia was experiencing its longest and worst drought, an event that caused the death of millions of head of cattle and widespread famine.

Venezuela, a country that has been facing for years of political and economic crises, resorted to nationwide power cuts in April 2016 due to drought which affected water levels at the Guri Dam. /p>

As for solutions, using floodwaters to replenish depleted aquifers and improving the health of agricultural soils so that they can better absorb water and store more carbon are just some of the methods that can to improve water resilience in a warming world, study finds.