Strongest hurricanes may double in frequency, study says

21 Jan 2010

The U.S. Southeast and the Bahamas will be pounded by more very intense hurricanes in the coming decades due to global warming, a new computer model suggests.

Warmer sea surface temperatures—which fuel hurricanes—and shifting wind patterns are expected to strengthen the storms, the study says.

(Related: “Strong Hurricanes Getting Stronger; Warming Is Blamed.”)

At the same time, rising temperatures should result in fewer weak or middling hurricanes in the western Atlantic. (See “Global Warming to Decrease Hurricanes, Study Says.”)

The study considered what would happen if people kept emitting more greenhouse gases until about 2050 and then started cutting emissions.

“Some refer to this as a middle-of-the-road scenario” for tackling greenhouse gas emissions, said study co-author Thomas Knutson, a research meteorologist with the U.S. National Oceanic and Atmospheric Administration (NOAA).

In this scenario the world became about 4.5 degrees Fahrenheit (2.5 degrees Celsius) warmer than today.

In turn, the western Atlantic Ocean—north of the Caribbean Sea up to the Carolinas—saw a doubling of category 4 and 5 storms, the most powerful kinds, by 2100. Today the Atlantic suffers an average of 14 of these intense hurricanes per decade.

Category 4 storms have sustained wind speeds of 131 to 155 miles (211 to 249 kilometers) an hour. Category 5 hurricanes have winds exceeding 155 miles (249 kilometers) an hour.

“I was quite surprised,” said Morris Bender, also a NOAA research meteorologist and the lead author of the new study, to be published tomorrow in the journal Science.

“I didn’t expect a doubling. I didn’t expect we’d see this much response.”

(Watch hurricane videos.)

“Unprecedented Results”

The new model is perhaps the most sophisticated yet to predict how hurricanes will change as the world warms, study co-author Knutson said.

The researchers combined state-of-the-art global climate simulations with “the hurricane prediction models used by weather forecasters and the [U.S.] Navy,” he said.

Combining three models into one tool, the scientists were able to simulate the entire Earth’s climate, with realistic hurricanes of all categories romping across the Atlantic.

The modeling method is a first, according to Judith Curry of the Georgia Institute of Technology, who was not involved in the study. “This is an important paper,” she said.

Kevin Trenberth of the National Center for Atmospheric Research, in Boulder, Colorado, said there’s still a lot of room for improvement in how all of today’s climate simulations represent hurricanes and the oceans.

Even so, the new study does bolster an emerging consensus on how climate change will affect hurricanes, added Trenberth, who also was not involved in the research.

“The best information we have now supports the view that tropical storms will likely decrease in number,” he said. “But the risk of category 4 and 5 storms could increase.”


books I've read on failure & grace

The World Without Us
The Last Oil Shock: A Survival Guide to the Imminent Extinction of Petroleum Man
A Paradise Built in Hell: The Extraordinary Communities That Arise in Disaster
Hell and High Water: Global Warming--the Solution and the Politics--and What We Should Do
The Worst Hard Time: The Untold Story of Those Who Survived the Great American Dust Bowl
The Tipping Point
Three Cups of Tea: One Man's Mission to Promote Peace... One School at a Time
The Upside of Down: Catastrophe, Creativity and the Renewal of Civilization
Out of Poverty: What Works When Traditional Approaches Fail
The Little Ice Age: How Climate Made History, 1300-1850
Confessions of an Eco-Sinner: Tracking Down the Sources of My Stuff
Deep Economy: The Wealth of Communities and the Durable Future
The Geography of Bliss: One Grump's Search for the Happiest Places in the World

Mason's favorite books »