Facts About How Global Warming Affects Hurricanes

Background

In summer 2005, Kerry Emanuel, a professor of meteorology at the Massachusetts Institute of Technology, published a paper in the scientific journal "Nature" showing that global warming had led to more hurricane destruction since the 1970s. Only weeks later, in late August 2005, Hurricane Katrina struck the Gulf of Mexico, particularly New Orleans and southern Louisiana, wreaking severe destruction and causing massive flooding. More than 1,500 people died, and more than 80 percent of New Orleans was flooded, with Katrina causing roughly $80 billion in property damage. As the costliest and one of the deadliest hurricanes in U.S. history, Katrina prompted greater scientific research on the link between global warming and hurricanes.

From 1880 to 2007, average temperatures around the world increased 1.4 degrees Fahrenheit (0.8 degrees Celsius). According to the Pew Center on Global Climate Change, about 90 tropical storms occur globally, on average, each year. The Intergovernmental Panel on Climate Change said in 2007 that there is "no clear trend" on the annual frequency of hurricanes. However, according to the Pew Center, the North Atlantic experienced an annual average of 10 tropical storms, including about five hurricanes, from 1850 to 1990. From 1998 to 2007, the average annual number of tropical storms was 15, including an average of eight hurricanes.

The sun's heat plays an important factor in the development of hurricanes, according to National Geographic. As the heat warms the surface of the ocean, causing evaporation, the heat and moisture rise into the atmosphere. As a result, clouds, scattered showers and thunderstorms are formed. Those thunderstorms combine with low-pressure systems to form a tropical depression, which is the first stage of a hurricane under development. The Earth's spin causes the winds to "whirl" around the center of the storm, solidifying it into a hurricane.

In 2010, a World Meteorological Association panel concluded in a study published in Nature Geoscience that, by the end of the 21st century, as a result of global warming, the overall strength of hurricanes (measured by wind speed) would increase by 2 percent to 11 percent. However, there would be from six to 34 fewer storms. This means there will be fewer weak and moderate storms, but an increase in the strongest, most destructive storms.