There are many ways to envision a hurricane

— as an enormously destructive wind, for example,or as a force that can drown a city. But hurricanes can be viewed in mechanical terms as well — as engines that are powered by heat from the ocean.

In an era of global warming, that can be a very troubling thought. If the Earth heats up, then so, too, should the oceans. While many factors go into hurricane formation, “you can say that all other things being equal, warmer water will allow storms to get stronger,” says James Kossin ’85, ’87 (BS Ma, MS Ma), a climate research scientist at the University of Wisconsin – Madison.

Though hurricane researchers had long suspected that warmer oceans would lead to stronger hurricanes, documenting that phenomenon was another matter. The collection of hurricane data has steadily improved as better instruments have come along, but researchers faced a roadblock as they tried to discern long-term trends in hurricane strength. The data from one decade, collected with less sophisticated equipment, didn’t match up with better data from the next.

So in 2007, Kossin and four other researchers crunched satellite weather data to render it consistent from year to year. In 2008, Kossin and colleagues James Elsner and Thomas Jagger of Florida State University used the homogenized data to look for long-term trends in hurricane velocity. “We studied every named storm around the world for 26 years, more than 2,000 in total.

inline“Our research showed that the strongest, most dangerous storms are getting stronger over time,” says Kossin. “It’s true globally, not just in the Atlantic Ocean, although the effect in the Atlantic is the most pronounced.” The strength of average storms was not affected.

“We’re saying that the most powerful storms have gotten, on average, four miles an hour stronger per decade between 1981 and 2006,” says Kossin. That comes to a 10-mile-an-hour increase in average hurricane strength over a quarter of a century.

“The 10-mile-an-hour difference between 200 and 210 miles an hour is a lot more damaging than an increase from 40 to 50 miles an hour,” explains Kossin. “Because of this, you might want to build fewer things in harms’ way, or you might want to build them a lot stronger.”

During this same 25-year period, global temperatures rose roughly two degrees Fahrenheit, while sea surface temperatures in the tropics, where hurricanes form, rose a little under one degree. “All of this suggests that global warming is making the strongest storms stronger,” Kossin says. The results of their analysis were published this year in the September issue of the journal Nature.

A Hurricane Scientist From New York

Kossin was born and raised in New York City, a metropolis seldom visited by hurricanes, and as he went through college, there was nothing to suggest that he would become one of the nation’s top figures in cyclone science.

Hurricane scientists, he observes, often come from the ranks of those who have lived through one in childhood. “The typical example is the child who experienced a hurricane as a seven year old. I’m not one of those.”

After high school, Kossin enrolled at Nassau Community College on Long Island, where he took classes by day and worked nights busing tables at an Italian restaurant owned by his girlfriend’s father. After earning an associates degree in computer science, he looked for a school to finish his undergraduate work. “Clarkson was one of the schools on my list, and they gave me a very generous scholarship that made it possible for me to attend.