What Did Climate Change Have To Do With Hurricane Michael's Strength? It's Complicated

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Hurricane Michael approached Florida with ferocious speed this week, hitting the Panhandle as a Category 4 hurricane and leaving behind a trail of catastrophic damage. The storm went from a depression to a serious storm in less than a week.

According the National Hurricane Center, Michael was the strongest hurricane to make landfall in the continental U.S. since Hurricane Andrew in 1992.

Though scientists will study Michael’s formation and course in the months to come, some have begun to question the impact of climate change on its speed and intensity.

As the storm closed in on the state, it hit waters that were 2 to 4 degrees above normal. Studies suggest a link between warmer waters and more energetic storms.

On Thursday, Senator Bill Nelson blamed global warming for how Michael grew from a tropical storm into such a monster. Michael is ranked the third strongest to hit the U.S. mainland by barometric pressure.

"Listen to the scientists at the National Weather Service, and they'll tell you that the Earth is heating up and the ferociousness of these storms is as a result, in part, of that heating up of the Earth,” Nelson said on CNN.

Though there may indeed be a link between a warming Gulf and the effects of storms, Bryan Norcross, a Hurricane Specialist for WPLG-TV in Miami, said Friday on The Florida Roundup that the full picture is more complex.

Research shows the average Gulf temperature has risen consistently over the last few decades. But historically speaking, it’s not uncommon in the Gulf of Mexico, or in Florida, for storms to intensify rapidly, he said.

“These kinds of hurricanes have happened over the years,” Norcross said. “In the waters around Florida, we have deep warm pools of water. In the Gulf of Mexico, if a hurricane goes over one of those deep warm pools -- like Katrina did, like Rita did -- it will blow up. It’s kind of dumb luck.”

Hurricane Andrew went from a Category 1 to a Category 5 in two days.

The science is advancing on the effects of climate change on hurricanes, and on rapid intensification, which is the term to indicate when the strongest winds within a storm increase by at least 30 knots (about 35 mph) in 24 hours. One study earlier this year found an increase in rapid intensification from 1986-2015 tied to warming water east of the Caribbean Sea.

This week, a UN group of scientists released a report warning of stronger storms, higher seas and hotter weather without unprecedented changes to limit global warming.

The report includes different scenarios, including one in the 2030s that could involve “a hurricane with intense rainfall ... associated with high storm surges [that destroys] a large part of Miami.”

Kate Stein, WLRN’s environmental reporter, said the report highlights the need for Florida to have a unified statewide plan to respond to climate change.

And Hurricane Michael underscores the need to look even further, she said: “not just climate,” Stein said, “but hurricanes and the connections between hurricane and climate.”

But it’s still difficult to both comprehend and communicate the direct impact of climate change on hurricanes.

Norcross pointed out that Florida is not suddenly seeing strong hurricanes where none existed before. (“A Category 4 hurricane hit Miami-Dade County in 1945, a Category 4 hit Broward in ‘47, a Category 4 hit Monroe in ‘48, a Category 4 hit Palm Beach County in ‘49, another Category 4 hit downtown Miami in 1950,” he said.)

The state is seeing hurricanes after a lull and in regions that have been drastically developed in recent decades, he said.

“The fact is that Florida is a precarious natural environment -- it always has been, it always will be,” Norcross said. Now “we’ve built these tremendous cities and these huge communities in this precarious natural environment -- without state leadership on how to do it in a resilient way. That’s fundamentally what’s got to change.”