Climate change means potential changes for hurricanes. NOAA scientists are using climate models to figure out trends as the atmosphere warms.
Senior scientist Tom Knutson shared three categories that are seeing some change: rainfall, sea level, and intensity.
“Those hurricanes that we simulate under warmer climate conditions have higher rainfall rates. And they’re slightly more intense…. And the models are projecting further warming into the future and further sea level rise,” said Knutson.
Knutson attributes sea level rise to two major players.
“Higher levels of CO2 in the atmosphere [are causing] the oceans to expand slightly, and that’s causing some, sea level rise. It’s called thermal expansion. Secondly, if you have ice on land that melts. Association with global warming and runs off into the ocean, that can also lead to more water in the ocean, basically. It’s gone from being on land in the ocean.”
As for intensity, Knutson says the two-degree Celsius scenario shows a 3% increase in wind speed intensity in the Atlantic Basin.
However, some trends are not clear-cut, one being the speed of storms. One study based on observations from the 1900s to the 21st century shows storms moving slower globally, but Knutson says their models have not picked up on this trend.
“The slowing down and stalling out of weather systems could be very important for things like these multi-day rainfall amounts if, in fact, we do have a greater occurrence of these storms stalling out. Some scientists think that that may be a global warming signal. But as I say, we’re just not seeing it clearly in our simulations. And so, we’re not sure exactly how to interpret the data,” Knutson said.
Also, Models still do not have a good grasp on the number of storms increasing or decreasing due to climate change; Knutson said it’s a work in progress.
