Ann Arbor (Informed Comment) – Florida Governor Ron DeSantis, on being asked about human-caused climate change, said he did not want to “politicize the weather.” Of course, it is not the weather that is at issue but climate, which is long-term and repeated weather patterns. DeSantis ducked the question because Koch Industries and ExxonMobil etc. are big donors to Republican candidates and he did not want to alienate them. DeSantis says that hurricanes are not more frequent now than in the twentieth century. But frequency is not the issue. Intensity is the issue. DeSantis turned down $350 million from the Biden administration for the green energy transition, of which governors like Michigan’s Gretchen Whitmer are making use to create jobs and slash carbon pollution.
With the beginning of the hurricane season, the climate is announcing that it is perfectly happy to politicize DeSantis.
Jeff Masters at Yale Climate Connections reports that the unusually hot ocean water in the Caribbean near Florida boosted the ferocity of Hurricane Idalia by 40% to 50%. There is more than one reason for the Caribbean to be unusually hot this year, including the El Nino, but a very large proportion of the extra heat can be laid to the door of human-caused climate change. We are pumping tens of billion of tons of carbon dioxide pollution into the atmosphere annually, a potent greenhouse gas that keeps more of the heat of the sun’s rays on earth. That extra heat in the atmosphere is being absorbed by the oceans, which are heating up, as well.
When it was still at the Yucatan Peninsula, Idailia started out weak. Its wind speeds increased as it neared the west coast of Florida, spurred on by the unusually hot waters in that area. If humans hadn’t heated up the water so much, it may have stayed a tropical storm or a cat 1. Hurricanes are now moving more slowly than they used to, even if their winds are blowing more fiercely, which means they now hover destructively over places for longer, doing more damage.
In addition, Chris Mooney and Kevin Crowe at WaPo show that climate scientists blame the freakish height of the wall of water or storm surge that Idalia slammed into some parts of the coast, at 6.89 feet at Cedar Key, on sea level rise. Melting ice at the poles contributes to rising sea level. So, too, does the heating of the water, since hot water expands and takes up more space than cold water. Both of these phenomena are a result of human-caused climate change. The Caribbean is about 9 inches higher now than in 1938, showing that sea level rise can affect some regions more than others. The oceans are not flat or all the same height. The Caribbean is rising faster than most other such bodies of water.
Obviously, Idalia would have caused much less flooding if the Caribbean had been lower. As it was, a third of the homes at Cedar Key were submerged.
Scientists have developed a scale for the strength of hurricanes, the Saffir-Simpson Hurricane Wind Scale, which rates them 1 to 5 depending on sustained wind speed.
A category 4 storm such as Idalia became shortly before its landfall is characterized by winds of 130-156 mph and it typically causes catastrophic damage, blowing off roofs, uprooting trees, and snapping power lines. Category 4 storms seem to have hit Florida roughly once a decade in the first half the the twentieth century, on average.
On making landfall, Idalia became a “high-end” category 3, with winds of 125 mph, and still able to do major damage to roofs, trees and power lines.
On Friday afternoon, two days after the hurricane hit, 100,000 Floridians were still without power.
The National Oceanic and Atmospheric Administration (NOAA) explains that to whip up a hurricane you need three basic ingredients. The first requirement is warm water. It has to be at least 80 degrees. In the old days, when I was young, it was a little unusual for ocean water to get up to 80 degrees. It happened but it was rare. So NOAA says that the second ingredient is moist air. You don’t have hurricanes in deserts. Dry air won’t do it. Then, third, winds have to strike up and converge on one another over the hot ocean.
Under certain conditions, the winds can whirl around one another and draw up heat energy from the warm ocean water. When they do that, they also build up moisture, since hot air can hold more water vapor than can cold air. The hotter the water under the hurricane, the greater are its wind speeds and the greater is the amount of water held by the storm. Since the hurricane cools down a bit when it makes landfall, it then dumps the water in the form of downpours. Coming off the warm ocean, the winds can still be energetic, as we saw with Idalia.
A place like the Caribbean had enough of these ingredients often enough so that there were occasionally hurricanes. They are becoming, however, ever more powerful and sustained, and they are causing higher storm surges, which is bad news for the Gulf coast. And that, Mr. DeSantis, is political.