Climate change is making hurricanes stronger

Our seas have been heating up in recent decades. In fact, the oceans have absorbed 90% of the global warming caused by climate change. Warm water is the key source of energy that powers tropical storms, including hurricanes. And Andra Garner, a climate scientist at Rowan University in Glassboro, New Jersey, has found that as the world warms, the rate at which hurricanes spawn and intensify from storms has doubled in the last 40 years…

Andra - We have seen our ocean waters warming in recent decades. Our oceans have actually taken up about 90% of the warming that's been caused by human caused climate change. And that warm water is a really key source of fuel for hurricanes that form in the ocean, including in the Atlantic. So I wanted to know if over that same time when we've seen our waters getting warmer, can we also see changes in how quickly hurricanes are strengthening?

Chris - And what did you see?

Andra - There are measurable and significant increases in how quickly storms are intensifying. So there were noticeable increases in the average fastest rate at which a hurricane in the Atlantic would strengthen. I also found changes, for example, in how often a hurricane goes from a pretty weak storm, say just a category 1 or a tropical storm into what we call a major hurricane. So category 3 or greater. And so I saw that from say the 1970s and ‘80s, up to 2001 to 2020, the chance for a hurricane to go from a weak storm into a major hurricane has more than doubled.

Chris - And so to what extent can we extrapolate this to other parts of the world because presumably the same physics is going to apply for other storms and other storm systems elsewhere and therefore it could mean that other places can expect an impact too.

Andra - Yeah, absolutely. You know, certainly I would like to take some of this work and really do the actual analysis for other regions, but as you're saying, the physics is kind of the same regardless of where you are. You know, having those warm ocean waters as well as other kinds of components for a hurricane, like fairly weak upper level winds are going to be important no matter where you are. So just earlier today we actually saw Hurricane Otis make landfall in Mexico and Hurricane Otis was in the Pacific. But it strengthened really, really quickly, going from a tropical storm to a category 5 hurricane in about 12 hours. So, I think that it's reasonable to expect that if we see some of these conditions that are really favourable for hurricanes to strengthen elsewhere as well, that we might see similar changes in the intensification rates for hurricanes there.

Chris - And the ultimate implication of what you found, what would that be?

Andra - Yeah, so I think there's a couple of take home points from this. One is that we have already seen changes in the last 50 years to the overall rates at which hurricanes are strengthening. And I think that tells us that we are already dealing with different conditions. And so our coastal communities around the Atlantic do need to be thinking about how they can prepare for the possibility that storms are strengthening more quickly, thinking about how we can maybe develop emergency action plans for our coastal communities that can adapt to this idea that a hurricane might strengthen quickly before making landfall. Just try and make those communities more resilient in that way. The other thing that I would say about these findings is that they should really serve as an urgent warning. We've seen the rates at which hurricanes strengthen greatly increase over the last 50 years. Over that same time, we've also seen changes to our ocean surface temperatures. We've seen our ocean waters getting warmer. And so I think that if we don't do something to limit additional warming, it's reasonable to expect that we might see this kind of pattern continue into the future.