Hurricanes Expected to Become Stronger

Hurricanes may become significantly stronger in the next few decades because of increasing amounts of carbon dioxide pollution in the atmosphere, a new study says.

If the atmosphere’s carbon dioxide content doubles, as forecast for the next century, the maximum possible intensity for hurricanes could rise 40% to 50% generally and 60% in the Gulf of Mexico, said the study in today’s issue of the British journal Nature.

Although only a few hurricanes reach maximum possible intensity, “we would tend to think, if the maximum intensity increases, the average would increase as well,” said Kerry Emanuel, associate meteorology professor at the Massachusetts Institute of Technology.

Projections for when the atmosphere’s carbon dioxide content will double range from about 2035 to 2080, with the equivalent of doubling by 2050 if the effects of other trace gases are taken into account, the National Center for Atmospheric Research reports.

Fossil Fuels

The carbon dioxide buildup, caused largely by the burning of fossil fuels, has long concerned scientists because it could cause a significant warming of worldwide climate. The warming could mean higher chances for extended heat waves and coastal flooding from higher seas, as well as impact on crop yields, scientists say.

Emanuel said his analysis assumes that the doubling of carbon dioxide will raise the temperature of ocean surfaces in tropical regions generally by about 2 degrees to 3 degrees Celsius, or about 4 degrees to 5 degrees Fahrenheit.

A warming in ocean surfaces increases the amount of heat energy that can be fed into a hurricane through evaporation, Emanuel said. Evaporation can occur only until the air becomes saturated, and warmer ocean surfaces allow more heat to be transferred before saturation takes place, he said.

The projections came from a computer simulation of average August conditions. The 40% to 50% increase in maximum intensity of hurricanes applies to most hurricane areas, such as the Caribbean Sea.