May 16, 2014 - Tropical storms appear headed for the Poles, peaking in ferocity at successively higher latitudes over the past three decades, according to a new study in the journal Nature. (Related: "Hurricanes 101.")
Climate scientists generally predict that tropical storms (called hurricanes, typhoons, or cyclones, depending on the ocean where they form) will increase in power but decline in frequency in coming decades due to global warming.
But the storms also appear to be on the move—driven by warmer oceans and wind-shear changes in the upper atmosphere—according to the Nature study, led by James Kossin of the NOAA National Climatic Data Center. "The poleward trends are evident in the global historical data," says the study.
Looking at satellite observations from 1982 to 2009—averaged across eight ocean basins—the researchers located the peak intensity of tropical cyclones, which they determined was occurring farther away from the equator.
In the Northern Hemisphere, the storms have moved an average of 33 miles (53 kilometers) north; and in the Southern Hemisphere 37 miles (60 kilometers) south. Despite fears raised by 2012's Superstorm Sandy, however, Atlantic hurricanes appear to have bucked the global migration by staying put. (Related: "Hurricane Sandy Report Warns of Rising Sea, More Storms.")
This map shows the seasonal intensity of hurricanes, typhoons, and tropical cyclones—all three names refer to the same phenomenon—since 1851 as recorded in NOAA's public archives.