April 3 (UPI) -- Today, drylands cover more than 40 percent of Earth's land surface. But according to a new study, that number is likely to increase in the coming decades as large swaths of the planet get hotter and drier.
Modeling efforts led by researchers from Washington State University suggest drylands are likely to become more abundant but less productive.
Some 38 percent of Earth's population lives on drylands, which consist mainly of savannas, grasslands and shrub lands. Drylands host important carbon sequestration processes, and provide acreage for grazing and non-irrigated croplands.
But according to the latest research, published this week in the journal Nature Communications, drylands are likely to support less and less vegetation as a result of climate change.
"Our results highlight the vulnerability of drylands to more frequent and severe climate extremes," lead study author Jingyu Yao, a research assistant at Washington State, said in a news release.
Researchers used rates of dryland expansion and productivity over the last several decades to model the effects of climate change on different dryland ecosystems. They found higher temperatures and declining precipitation levels are likely to leave most drylands vulnerable to degradation.
The visual effects of dryland degradation can already be observed across the planet.
In Mongolia, rising temperatures, diminishing precipitation and overgrazing have combined to degrade the country's grasslands. Across the American Southwest, invasive species have turned once-green drylands brown. Australia's drylands has suffered the effects of longer, more intense drought conditions, leaving the continent drier and more vulnerable to wildfire.
Drylands host important carbon cycle processes, but because these ecosystems are more sensitive to temperature and precipitation, carbon cycles on drylands are prone to wild variability.
Researchers hope their paper will inspire stronger efforts to protect drylands from climate change.
"In our society, we are not paying much attention to what's going on with dryland regions," said co-author Heping Liu, professor of civil and environmental engineering at Washington State. "Given their importance in global carbon cycling and ecosystem services, a global action plan involving stringent management and sustainable utilization of drylands is urgently needed to protect the fragile ecosystems and prevent further desertification for climate change mitigation."