Climate change is turning more of Central Asia into desert

Climate change is turning more of Central Asia into desert

Climate change is turning more of Central Asia into desert

Two camels walk through the desert in Uzbekistan

The spread of deserts in Uzbekistan and neighboring countries will change the composition of ecosystems.Credit: Matyas Rehak/Shutterstock

As global temperatures rise, desert climates have spread as far north as 100 kilometers in parts of Central Asia since the 1980s, a climate analysis shows.1

The study, published May 27 in Geophysical Survey Letters, also found that temperatures have risen over the past 35 years throughout Central Asia, including parts of China, Uzbekistan and Kyrgyzstan. During the same period, mountain areas have become hotter and wetter – possibly accelerating the retreat of some large glaciers.

Such changes threaten ecosystems and those who rely on them, said Jeffrey Dukes, an ecologist with the Carnegie Institution for Science’s Department of Global Ecology in Stanford, Calif. The findings are a “great first step” toward informing mitigation and adaptation policies, he says.

Dryer and hotter

More than 60% of Central Asia has a dry climate with little rainfall. With little water available for plants and other organisms, much of the region is vulnerable to rising temperatures, which encourage water evaporation in the soil and increase the risk of drought. Previous research on climate change has reported mean changes in temperatures and rainfall for large parts of Central Asia23 but that provided limited localized information for residents, said study co-author Qi Hu, an earth and climate scientist at the University of Nebraska-Lincoln. “We need to know the important subtleties of climate change in specific areas,” Hu says.

Hu and climate scientist Zihang Han of Lanzhou University in China used air temperature and precipitation data from 1960 to 2020 to divide Central Asia into 11 climate types.

They found that since the late 1980s, the desert-climate region has expanded eastward and spread as far north as 100 kilometers to the north in northern Uzbekistan and Kyrgyzstan, southern Kazakhstan and around the Junggar Mountains. basin in northwestern China. Hu says this is a significant expansion and has had a knock-on effect on neighboring climate zones, which have also become drier. In some areas, the annual mean temperature between 1990 and 2020 was at least 5 °C higher than between 1960 and 1979, with summers becoming drier and rain falling mainly in winter.

Over time, increasing temperatures and decreasing rainfall will cause plant communities to be dominated by species adapted to warmer and drier conditions, Dukes says. “That has consequences for, among other things, the grazing animals that depend on the steppe or the grasslands,” he says. In some regions, he adds, prolonged periods of drought will reduce land productivity until it becomes “dead” ground.

Warmer and wetter

The team found a different situation in mountain areas. In the Tian Shan Mountains of northwestern China, rising temperatures have been accompanied by an increase in the amount of precipitation that falls as rain rather than snow. Higher temperatures and more rainfall are contributing to high-altitude ice melting, which could explain the unprecedented rate of shrinkage of glaciers in this range, Hu says.

With a reduction in snowfall, glaciers in Central Asia will not replenish the lost ice, meaning less meltwater will flow to people and crops in the future, says Troy Sternberg, a geographer at the University of Oxford, UK.

Global problem

Desertification is a problem in Central Asia and other parts of the world, said Mickey Glantz, a climate scientist at the University of Colorado Boulder. But to definitively conclude that deserts are expanding, researchers need to look at indicators such as dust storms and heat waves, rather than relying solely on climate classification.

Human activities such as mining and farming also contribute to desertification, Sternberg notes. So governments in Central Asia should focus on sustainable agriculture and urbanization, he says. “Central Asia, like the rest of the world, needs to pay attention to the changing climate and try to adapt better to it.”