More than 40% of Earth’s land could become arid by 2100

More than 40% of the world’s land area, excluding Antarctica, could become arid by the end of the century, according to a new study published in Environmental Research Letters and led by researchers at the Chinese Academy of Forestry.

The study estimates that the expansion of dry conditions could affect an additional 2.37 million square kilometers of land compared with the 1994-2023 baseline period. The area is roughly eight times the size of Italy.

Australia is expected to be the region most severely affected, followed by eastern Brazil and parts of northern and southern Africa.

The researchers, led by Yifei Cai, warned that the spread of climatic conditions typically associated with arid regions into areas that were previously wetter could intensify water shortages, accelerate ecosystem degradation and contribute to desertification.

“Expanding arid climate conditions into previously wetter regions could aggravate water scarcity, ecosystem degradation and desertification, creating challenges for global sustainable development,” the researchers said.

To assess how dry conditions could evolve, the researchers used a forecasting method that also takes into account the impact of rising atmospheric carbon dioxide levels. Although carbon dioxide is a major driver of climate change, the researchers found that higher concentrations of the gas could have an unexpected effect by slowing the expansion of some arid areas.

The study also projects a significant increase in the planet’s hyperarid regions, which are considered the driest environments on Earth. In these areas, annual evaporation from soil and vegetation is at least 20 times greater than the amount of precipitation they receive.

Hyperarid zones currently account for around 7.5% of the world’s land area and include some of the planet’s most extreme deserts, such as the Sahara in Africa and the Atacama in Chile.

The findings highlight the potential for climate-driven changes in global aridity to put additional pressure on water resources and ecosystems in the decades ahead.