Hurricanes Irma and Harvey have reignited discussions about the link between global warming and extreme weather, with climate scientists now saying they can show the connections between the two phenomena better than ever before.
Scientists’ explanation of how they do that involves a complex discussion of climate models, historical temperature data and probability. But understanding the link really comes down to one figure: the air can hold 7% more water with every degree Celsius that the temperature rises. That figure comes from the Clausius–Clapeyron equation, a widely accepted physical law established centuries ago long before any politicized debate on climate change.
“A warmer ocean makes a warmer atmosphere, a warmer atmosphere can hold more moisture,” says Gabriel Vecchi, a professor of geosciences at Princeton University who studies extreme weather events. “So, all other things equal, the same storm in a warmer planet would give you more rainfall.”