With global temperatures rising, the desert climate has spread northward about 100 miles [100 km] to parts of Central Asia since the 1980’s, a meteorological survey reveals.The study, published May 27 in Geophysical Research Letters, also found that over the past 35 years, temperatures have risen throughout Central Asia, including parts of China, Uzbekistan, and Kyrgyzstan. At the same time, mountainous areas have become very hot and humid – which is likely to slow down some of the major glaciers.Such changes threaten ecosystems and those who rely on them, says Jeffrey Dukes, a biologist at the Carnegie Institution for Science’s Department of Global Ecology in Stanford, California. The findings are a “first major step” in informing the reduction and adaptation policies, he says.
Drought and heat
More than 60% of Central Asia has a dry climate with exceptional rainfall. With less water available to plants and other organisms, much of the region is at risk of rising temperatures, which in turn increases evaporation and increases the risk of drought. Previous climate change studies have reported moderate changes in temperature and rainfall in large parts of Central Asia 2.3 but have provided limited local knowledge to residents, says another study author Qi Hu, a Earth scientist and climate scientist at the University of Nebraska-Lincoln. “We need to know the important tricks of climate change in some areas,” said Hu.
Hu and meteorologist Zihang Han at Lanzhou University in China used air temperature and rainfall data from 1960 to 2020 to divide Central Asia into 11 climate zones.They found that since the late 1980’s, what is considered to be a desert climate has expanded eastward, extending about 60 miles [100 km] north of Uzbekistan and Kyrgyzstan, south of Kazakhstan and near the Junggar Basin in northwestern China. Hu says this is a major stretch and has had a significant impact on the surrounding areas, which are also very dry. In some areas, the average annual temperature was at least 5 ° C between 1990 and 2020 than it was between 1960 and 1979, when the summer began to dry out and the rains were heavier in winter.Over time, rising temperatures and declining rainfall will see plant communities dominated by species accustomed to extreme hot and dry conditions, Dukes said. “That will have consequences for things like grazing animals that rely on groups or grasslands,” he said. In some regions, he adds, extended periods of drought will reduce land production until the soil is ‘dead’.
Warm and wet
The group found a different situation in mountainous areas. In the Tian Shan region of northwestern China, rising temperatures are accompanied by an increase in rainfall than snow. High temperatures and rising rainfall contribute to melting glaciers at higher altitudes, which could explain the unprecedented level of glaciers on the plateau, Hu said.
With the reduction of snowfall, glaciers in Central Asia will not fill in the lost ice, which means less melting water will flow to humans and plants in the future, says Troy Sternberg, a geologist at the University of Oxford, UK.
A global problem
Desertification is a problem in Central Asia and other parts of the world, says Mickey Glantz, a meteorologist at the University of Colorado Boulder. But to conclude that deserts are growing, researchers should look for indicators such as dust storms and heat waves, rather than relying solely on climate change.Human activities such as mining and agriculture also contribute to the expansion of the desert, notes Sternberg. Central Asian governments should therefore focus on sustainable agriculture and urbanization, he said. “Central Asia, like the rest of the world, needs to be aware of a changing climate and try to adapt.”
Source Journal Reference:GiorgiaGuglielmi, Climate change is turning more of Central Asia into desert, Nature news (2022), https://www.nature.com/articles/d41586-022-01667-2
