A Florida climate scientist says hurricanes are intensifying and becoming more frequent
"As we increase the temperature of the atmosphere... the air that is all around us can hold more water," said Daniel Gilford of Climate Central. "There's been about a 10% increase in atmospheric moisture and rainfall associated with Hurricane Ian."
Hurricane Ian was among the strongest storms to ever make landfall in Florida and scientists say climate change contributed to that. WUSF's Jessica Meszaros spoke with Daniel Gilford, a climate scientist with the nonprofit Climate Central, about global warming's effect on Ian and what it could mean for future storms.
What about Hurricane Ian screams climate change to you?
There's probably two main things: One is that Hurricane Ian exists in an environment that we know human beings have been changing over the past century or so. As human beings emit greenhouse gases, those greenhouse gases go up into the atmosphere, they warm up the planet, kind of by pulling the blanket tighter around the planet, warming it up. That warmer air gets down into the water, and warmer water means more fuel for hurricanes to sort of eat up as they pass over the warm waters of say, the Gulf of Mexico.
That's in part what happened here: Ian sort of matured in an environment that was very conducive to being an strong tropical cyclone, a strong hurricane, because of the warm waters that were sort of there. We know there's a very clear link in climate change between the rapid intensification that is sort of the quick development of a hurricane from a tropical storm or sort of a Category One, Category Two, say, all the way up to Category Four, where it made landfall that is sort of encouraged by warmer sea surface temperatures — which we definitely saw going very deep down into the Gulf of Mexico before Ian's landfall.
The second part of it that is more sort of substantive that we can even say right now we know that climate change affected is that there's increased water vapor in the atmosphere because of human activities. As we increase the temperature of the atmosphere, there's the sort of air that is all around us can hold more water. I had some colleagues who have done some research recently that have shown there's been about a 10% increase in atmospheric moisture and rainfall associated with Hurricane Ian.
Rising temperatures are fueling hurricanes, right? And that leads to more Category Fours and Fives. Is there anything else that people should know who live in Florida about climate change about how they are in fact affecting storm activity?
Yeah, so I mean, we know that hurricanes are more likely than not slowing down in response to climate change. There's a sort of reduction the speed at which hurricanes move along the surface of the earth. What that means is because they are moving more slowly, they can sit in certain places for longer periods of time.
Also, we are increasing the sea levels around us. We cannot forget, as we increase the temperature of the atmosphere and the ocean, ice melts at our poles, in our mountain glaciers — that increased water from ice melt, as well as increased sea surface height because of the expansion of the ocean as it warms — both of those things contribute to sea level rise.
We've already seen in some parts of the state of Florida over a foot of sea level rise. And when the storm comes on shore and brings the water along with it, it is bringing that extra water that we have added as a society through sea level rise with the storm and that means that there is a higher potential for flooding in areas along the coastline when a storm arrives. And indeed, during Hurricane Ian, we saw incredible amounts of flooding damage in the southwest that is consistent with sea level rise, sort of adding additional risk to the communities in the state.
Floridians are characteristically unafraid of hurricanes. I've heard some say we've been through this before. What would you say to skeptics who don't know why after years of hurricanes before we'd be talking about hurricanes in the context of climate change now?
Yes, we have experienced intense hurricanes in the past, but these hurricanes are getting worse. And we're getting more of them, higher volume of Category Four, Category Five storms, which increases the likelihood that you're going to face dangerous conditions during your lifetime if you live in the state of Florida.