Future hurricanes may be worse than Harvey

How powerful would Hurricane Harvey have been in 1880? How much stronger might it be in 2100?

A single Hurricane Harvey has been more than anyone can bear. But to better prepare cities for future storms, researchers are preparing to re-watch Harvey thousands of times. They’ve already been studying earlier storms, and their conclusions don’t bode well for the decades to come.

In the months and years after Superstorm Sandy’s 2012 assault on New Jersey and New York, Gary Lackmann, an atmospheric science professor at North Carolina State University, was asked how the event might be understood in light of human-driven global warming. He knew that the question everyone wants answered-did climate change cause the storm-wasn’t the right one. Hurricanes were around long before the industrial revolution. Two questions did, however, resonate:

How does climate change affect the frequency or intensity of huge storms? And what would the weather pattern that sustained Sandy have spawned in a cooler past or a hotter future?

The first question is the more difficult one, though research has shown that the future will likely see more intense storms, even if there may be fewer overall. Asking the second question, however, might lead to useful conclusions about weather extremes, he felt. Lackmann spent the past several years gleaning insight from atmospheric research models of violent storms, such as Hurricane Floyd in 1999 and the flooding in the south-central U.S. in 2010, in an effort to answer question number two.

The biggest impact multiplier is human decisions on the ground.

No two storms are identical, particularly Sandy and Harvey. “Sandy didn’t stall,” Lackmann notes. Nor did, for example, Hurricane Irene in 2011 or Matthew last year. Harvey’s destructive holding pattern in and around Houston has placed stalling storms front-of-mind for hurricane researchers. Whether there’s been a change in high-level wind patterns that “steer” storms is of paramount importance, according to Kerry Emanuel, atmospheric science professor at the Massachusetts Institute of Technology.

One challenge that Lackmann identified is pinpointing whether storms really are slowing down, and consequently dumping more water where people live. Hurricane Easy in September 1950 looped around Florida’s central Gulf Coast and dropped more than 45 inches of rain over the course of a week. Hurricane Flora poured 100 inches on Santiago de Cuba, in Cuba, in October 1963.

“These events have happened before,” Lackmann said. “It would be very difficult to say that Harvey stalled because of climate change. It would be difficult to ever truly sort that out.”