Scientists say Harvey may be the soggy sign of future storms

WASHINGTON — By the time the rain stops, Harvey will have dumped about 1 million gallons of water for every man, woman and child in southeastern Texas — a soggy, record-breaking glimpse of the wet and wild future that global warming could bring, scientists say.

While scientists are quick to say that climate change didn’t cause Harvey and that they haven’t determined yet whether the storm was made worse by global warming, they do note that warmer air and water mean wetter and possibly more intense hurricanes in the future.

“This is the kind of thing we are going to get more of,” said Princeton University climate scientist Michael Oppenheimer. “This storm should serve as warning.”

There’s a scientifically accepted method for determining if some wild weather event has the fingerprints of man-made climate change, and it involves intricate calculations. Those could take weeks or months to complete, and then even longer to pass peer review.

In general, though, climate scientists agree that future storms will dump much more rain than the same size storms did in the past.

That’s because warmer air holds more water. With every degree Fahrenheit, the atmosphere can hold and then dump an additional 4 percent of water (7 percent for every degree Celsius), several scientists say.

Global warming also means warmer seas, and warm water is what fuels hurricanes.

When Harvey moved toward Texas, water in the Gulf of Mexico was nearly 2 degrees (1 degree Celsius) warmer than normal, said Weather Underground meteorology director Jeff Masters. Hurricanes need at least 79 degrees F (26 C) as fuel, and water at least that warm ran more than 300 feet (100 meters) deep in the Gulf, according to University of Miami hurricane researcher Brian Mcnoldy.