Surf's Up! (Beware)

Finally, something to look forward to as the world warms due to greenhouse gases: bigger waves along the United States’ east coast. It probably won’t be enough to make surf shops on Maui or in Santa Barbara worry about new competition for boarders, but the increased wave heights promise to give eastern surfers something more challenging than they’re used to.

Although the rise in sea level due to global warming gets all the attention, the effect of warming on wave heights promises, or threatens, to be just as dramatic.Analyzing data from one ocean buoy in the Gulf of Mexico about 200 miles south of Louisiana and three along the central eastern shore from off South Carolina to off New Jersey—operated by the National Data Buoy Center—going back to the 1970s, scientists have found that wave heights during the summer have risen steadily over the last three decades.

Big waves were both higher and more common starting in the mid-1990s than they were earlier, Paul Komar of Oregon State University and Jonathan Allan of the Oregon Department of Geology and Mineral Industries report in the Journal of Coastal Research. The largest ones now measure about 30 feet, compared to about 21 feet in decades past.

The reason: the greater intensity of tropical storms that charge up the Atlantic coast. A warmer atmosphere packing more moisture and forming cyclonic storms above warmer seas adds up to stronger hurricanes (see p. 239 and 304 of the most recent report of Working Group 1 of the Intergovernmental Panel on Climate Change). Stronger hurricanes, even those that do not make landfall, stir up the seas enough to generate greater waves. Surf’s up!

More ominously, of course, bigger waves mean more beach erosion, storm surges and similar destruction. So while boarders may rejoice in the new surf conditions along the eastern seaboard, people on dry land will likely see it very differently.