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Climate — Drier air

A new analysis shows projected changes in annual aridity for the years 2071-2100 compared to 1985-2014. Brown shadings indicate drier conditions. Black dots indicate statistical significance at the 90% confidence level. Credit: Jiafu Mao/ORNL, U.S. Dept. of Energy

A new analysis from Oak Ridge National Laboratory shows that intensified aridity, or drier atmospheric conditions, is caused by human-driven increases in greenhouse gas emissions. The findings point to an opportunity to address and potentially reverse the trend by reducing emissions.

Scientists examined the underlying causes for these long-term changes in global aridity using a multipronged approach and a wealth of observational data from 1965 to 2014.

The research team projects that large-scale dryness will continue to increase through the end of this century. Their model results, which are constrained by historical observations, project more aridification than original Earth system models.

“We used rigorous detection and attribution methods to disentangle the human fingerprints from natural factors,” said ORNL’s Jiafu Mao. “Natural variability alone cannot explain increasing aridification at long timescales. We can say with high statistical confidence that anthropogenic drivers, primarily greenhouse gas emissions, are causing these changes in climate.”