Megadrought ‘likely to hit the western US by end of century’

The southwestern US is no stranger to droughts. California is currently in one of the worst droughts on record for the state. But new research brings more ominous warnings for the Southwest and the Midwest regions – a megadrought is likely to occur in the western US by the end of the century, all thanks to climate change.

The report, published in the journal Science Advances, noted that the severity of the megadrought will be determined by the levels of greenhouse gas emissions. By aggressively cutting emissions we can effectively curb its severity, but if no action is taken to reduce GHG emissions, there is an 80% likelihood of a decades-long megadrought occurring, the scientists say.

A megadrought is a natural hazard much like hurricanes and tornadoes. But unlike their stormy counterparts, megadroughts wreak havoc for much longer, lasting decades.

The team of researchers from NASA and Cornell University compared future drought projections to drought records from the last 1,000 years – the first study ever to do so. The projected droughts in the US Southwest and Central Plains will be drier, longer, and with higher regional temperatures than anything seen in those regions in the past millennium.

Megadrought top
Megadrought bottom
The high emissions scenario (top photo) projects the severity of the megadrought if we do not make substantial cuts to GHG emissions. The moderate scenario (bottom photo) shows the possible (and significant) difference in drought severity if we really work to slash into our GHG emissions.
NASA’s Goddard Space Flight Center

The scientists analysed tree rings to understand past droughts, a drought severity index, and soil moisture data sets from 17 climate models to estimate the drought risk in the 21st century. Let’s hope that soil moisture data from SMAP doesn’t spell out even drier doom for the area.

Read on to hear from one of the authors himself, Jason Smerdon, discuss the report and its findings.

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