Climate change is clearly making some regions wetter and others drier. But it’s been difficult for scientists to detect a clear, consistent human role in increasing the frequency and severity of global droughts given natural climate variability, regional differences, and limited data.

A new report in Nature adds evidence to the suspicion that air pollution could be complicating the science, masking the role of greenhouse gases on droughts.

Research has already found that air pollution has likely moderated the level of global warming (see “We’re about to kill a massive, accidental experiment in reducing global warming”). The newest findings suggest this could have played a role in reducing droughts as well, likely by decreasing the level of soil-moisture drying that would have otherwise occurred.

If so, as the world continues to clean up air pollution, the impact of climate change on droughts will get even more severe.