By Earth Institute at Columbia U – Re-Blogged From EurekAlert
About a dozen megadroughts struck the American Southwest during the 9th through the 15th centuries, but then they mysteriously ceased around the year 1600. What caused this clustering of megadroughts — that is, severe droughts that last for decades — and why do they happen at all?
If scientists can understand why megadroughts happened in the past, it can help us better predict whether, how, and where they might happen in the future. A study published today in Science Advances provides the first comprehensive theory for why there were megadroughts in the American Southwest. The authors found that ocean temperature conditions plus high radiative forcing — when Earth absorbs more sunlight than it radiates back into space — play important roles in triggering megadroughts. The study suggests an increasing risk of future megadroughts in the American Southwest due to climate change.
