Some climate models underestimate risk of future floods

Commonly used climate models may be significantly underestimating the risk of floods this century, according to a new study by Yale researchers.

Accurately pinpointing the magnitude and frequency of extreme rainfall hinges not only on tracking rainfall, but also on the way researchers model climate change, the study says. Previous studies averaged all the available climate models in order to figure out how much rain the planet will get in coming decades, but the Yale researchers only used the group of models that predict that climate change will result in an increase in precipitation efficiency—how much of a falling raindrop reevaporates into the atmosphere before it hits Earth’s surface.

They excluded models that forecast a decrease, since scientific observations over the past two decades indicate that climate change is yielding an increase in precipitation efficiency. The results show that it is possible that there will be as much as a twofold increase in the volume of extreme rainfall in the 21st century compared to what previous studies estimated.

Lawmakers could help prepare for extreme rainfall via fund initiatives that harden home infrastructure, such as rooftops, and improve drainage systems.