The damage caused by Hurricane Sandy is prompting people to ask exactly how the storm is related to climate change. Category 1 hurricanes are typical October fare, and Sandy’s collision with another storm is unusual, says Chris Mooney at Mother Jones.
Scientists are careful to say there are uncertainties, but increased precipitation, ocean temperatures, sea level height, hurricane size and compounding storms can all be tied to a destabilizing climate.
Experts “agree that global warming has added more moisture to the atmosphere,” which gives more water mass to a storm, Mooney says. Elevated sea levels enable water to travel farther inland, and increased ocean temperatures “are jet fuel for hurricanes.”
4. Massive size: The most striking and destructive aspect of Sandy is its breadth—tropical-storm-force winds reached a radius of 520 nautical miles at one point yesterday.* Apparently only one storm in the Atlantic region has had a larger wind field, and of course, bigger storms drive bigger storm surges and damage larger areas when they make landfall. So is global warming involved in making storms bigger, overall? According to MIT hurricane expert Kerry Emanuel, it might be—but probably only a little. “For ordinary hurricanes, we actually expect a little increase in the size, based upon recent work we’ve done,” Emanuel explains. “Not spectacular, but a little increase in size.”
5. Hybrid storms and climate change: Sandy, continues Emanuel, is a “hybrid storm”—in other words, it has characteristics of tropical cyclones (hurricanes) that get their energy from the warm ocean surface, but also of winter cyclones that get their energy from temperature contrasts in the atmosphere. Such hybrids do occur around the world with some regularity, but how is global warming changing them? That’s less clear, Emanuel remarks. Unlike for hurricanes, “nobody has bothered to compile a comprehensive climatology of hybrid storms,” he says. “So there’s nowhere to go to see the characteristics of these storms changing.”