2012-10-30. Did Climate Change Cause Hurricane Sandy? |

posted Nov 1, 2012, 3:38 PM by Alan Gould
By Mark Fischetti, Scientific American. An article relevant to GSS Climate Change chapter 8. Excerpt:  If you’ve followed the U.S. news and weather in the past 24 hours you have no doubt run across a journalist or blogger explaining why it's difficult to say that climate change could be causing big storms like Sandy. …The hedge expressed by journalists is that many variables go into creating a big storm, so the size of Hurricane Sandy, or any specific storm, cannot be attributed to climate change. That’s true, and it’s based on good science. However, that statement does not mean that we cannot say that climate change is making storms bigger. It is doing just that—a statement also based on good science, and one that the insurance industry is embracing, by the way. … Hurricane Sandy got large because it wandered north along the U.S. coast, where ocean water is still warm this time of year, pumping energy into the swirling system. But it got even larger when a cold Jet Stream made a sharp dip southward from Canada down into the eastern U.S. …Here’s where climate change comes in. …Recent research by Charles Greene at Cornell University and other climate scientists has shown that as more Arctic sea ice melts in the summer—because of global warming—the NAO [A climate phenomenon called the North Atlantic Oscillation] … more likely … makes the Jet Stream … move in a big, wavy pattern across the U.S., Canada and the Atlantic, causing the kind of big southward dip that occurred during Sandy. Climate change amps up other basic factors that contribute to big storms. For example, the oceans have warmed, providing more energy for storms. And the Earth’s atmosphere has warmed, so it retains more moisture, which is drawn into storms and is then dumped on us. … if you’re a regular Scientific American reader, you might recall that another well-regarded scientist predicted behemoths such as Sandy in 2007. The article, by Kevin Trenberth, a senior scientist at the National Center for Atmospheric Research, was presciently titled, "Warmer Oceans, Stronger Hurricanes." Trenberth’s extensive analysis concluded that although the number of Atlantic hurricanes each year might not rise, the strength of them would. … Munich Re, one of the world’s largest reinsurance firms, issued a study titled "Severe Weather in North America.” …the report identified global warming as one of the major culprits: “Climate change particularly affects formation of heat-waves, droughts, intense precipitation events, and in the long run most probably also tropical cyclone intensity." Read the full article: http://blogs.scientificamerican.com/observations/2012/10/30/did-climate-change-cause-hurricane-sandy/