Droughts of tens of years are known to have occurred in the southwestern United States over the past two millennia, but model simulations suggest that much longer 'megadroughts' might occur in a future, warmer climate. So far, the presence of such droughts in the palaeoclimatic record has been unclear. Now, a lake sediment core from northern New Mexico is analysed, showing that millennial-scale megadroughts were a regular feature of Pleistocene interglacials. The results suggest that, in the absence of anthropogenic warming, the southwestern United States would probably be entering a cool and wet phase.
- Peter J. Fawcett
- Josef P. Werne
- Craig D. Allen
