Hurricane Harvey and Climate Change

After rapidly scaling up in strength, Hurricane Harvey has dumped an ‘unprecedented’ amount of rainfall onto Houston, Texas. Lives have been lost, homes flooded, and officials estimate the damages may make this one of the costliest natural disasters in U.S. history.

But inevitably, Americans want to know just how ‘natural’ this disaster really was, and what role climate change may have played. IRI’s Chia-Ying Lee and Adam Sobel, who runs the Columbia Initiative on Extreme Weather and Climate, explain what we can and can’t conclude about climate change and Harvey in this video:

Climate scientists are fairly certain that climate change will, on average, make hurricanes stronger. “We know the atmosphere is getting warmer, and the oceans are getting warmer,” explains Lee, who is also a fellow at the Center for Climate and Life.

Hurricanes are driven by ocean heat, and some scientists have pointed out that the Gulf of Mexico was warmer than average this year. Hurricane Harvey rapidly transformed from a tropical storm to a Category 4 behemoth as it sucked energy off those particularly warm waters. Making matters worse, warmer air is able to hold more water, and more water vapor can lead to more rain, so scientists expect that a warming world will have more heavy downpours.

For now, that’s about all that anyone can say with much certainty. It sure seems as if climate change contributed to Hurricane Harvey, but it’s not certain yet, and if it did, scientists would want to know by how much? “It’s just very hard to say much without more study,” says Lee. Climate scientists will never be able to say that climate change “caused” a particular extreme weather event. A popular analogy is a baseball player on steroids: we know doping makes the player stronger, but we can’t say for sure whether any particular home run was the result of the steroids. What climate scientists can do is calculate the likelihood that climate change made an extreme weather event stronger.

Find out how by reading the full story on the Earth Institute’s State of the Planet blog.