New Megadrought may be worst in 1000 years

If you're living in the West, you may want to start thinking about conserving your water. A group of scientists from NASA, Columbia University, and Cornell University have published a paper in Science Advances which suggests a 35-year drought – or "megadrought," as they call it – will be hitting the Southwest and central Great Plains in the near future. This will happen, they say, if we stay on our current trajectory of greenhouse gas emissions. If emissions continue as they are, there's an 80% chance, this team says, that we'll hit at least one "decades-long" megadrought between the years 2050 and 2100.

A presentation was made at the February 12th AAAS meeting by this team at the same time as their paper was published in this week's Science Advances. Their findings are based on 17 state-of-the-art climate models which project soil moisture over the next 100 years.

Using 1800 tree-ring chronologies collected from across the United States, this team created a 1000-year map of past drought periods. They suggest that there's been no drought comparable to the scale of the one they're forecasting. No drought this large – not over the entire 1000-year history they researched.

Even if CO₂ emissions are "dramatically reduced," they say, the drought they're predicting will be "unprecedented."

ABOVE: Multimodel mean summer (JJA) PDSI and standardized soil moisture (SM-30cm and SM-2m) over North America for 2050–2099 from 17 CMIP5 model projections using the RCP 8.5 emissions scenario.

Above you'll see the team's tree-ring data from the NADA showing JJA PDSI. The wavy line you see there shows droughts over the past 1000 years.

When it dips, it's not very moist.

As you can see in the projected statistics there over the next 100 years – we may well be in big trouble.

Above you'll see a presentation made by NASA Goddard on the drought. Near the start of this video you'll see Ben Cook, NASA Climate Scientist speak on the possibilities and the consequences of our actions – or inaction, as it were.

The authors of this paper are Benjamin I. Cook, Toby R. Ault, and Jason E. Smerdon.* The paper can be found with DOI: 10.1126/sciadv.1400082, and goes by the title "Unprecedented 21st century drought risk in the American Southwest and Central Plains."

*Benjamin I. Cook 1,2,*, Toby R. Ault 3, and Jason E. Smerdon 21. NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA.2. Ocean and Climate Physics, Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964, USA.3. Earth and Atmospheric Sciences, Cornell University, Ithaca, NY 14853, USA.