Warmer seas linked to strengthening hurricanes: FSU study fuels global warming debateSeptember 04, 2008TALLAHASSEE, Fla. -- The theory that global warming may be contributing to stronger hurricanes in the Atlantic over the past 30 years is bolstered by a new study led by a Florida State University researcher. The study will be published in the Sept. 4 edition of the journal Nature. Using global satellite data, FSU geography Professor James B. Elsner, University of Wisconsin-Madison Professor James P. Kossin and FSU postdoctoral researcher Thomas H. Jagger found that the strongest tropical cyclones are, in fact, getting stronger -- and that ocean temperatures play a role in driving this trend. This is consistent with the "heat-engine" theory of cyclone intensity. "As seas warm, the ocean has more energy that can be converted to tropical cyclone wind," Elsner said. "Our results do not prove the heat-engine theory. We just show that the data are quite consistent with it."
Kerry Emanuel of the Massachusetts Institute of Technology first suggested the possible connection between global warming and increases in tropical cyclone intensity in a 2005 paper. He linked the increased intensity of storms to the heating of the oceans, which has been attributed to global warming. Critics argued that the data were not reliable enough to make assertions about the relationship between climate change and hurricanes. Moreover, when scientists looked at the mean tropical cyclone statistics, they did not see an upward trend. Elsner's team addressed both issues by using globally consistent, satellite-derived tropical cyclone wind speeds as opposed to the observational record and by focusing on the highest wind speeds of the strongest tropical cyclones each year. Emanuel's theory is that the intake of warm air near the ocean surface and the exhaust of colder air above the cyclone is what drives a hurricane. Other factors being equal, the warmer the ocean, the warmer the intake of air. This heat-engine theory of how hurricanes increase their intensity is well accepted, but there are many environmental factors, such as wind shear, that might prevent a hurricane from strengthening, Elsner said. To address that problem, Elsner's team looked at a subset of hurricanes that are closest to their maximum possible intensity (MPI). Under the heat-engine theory, every storm will lose some energy through inefficiency, and that loss will limit the storm's potential. The MPI represents the storm's maximum potential under ideal environmental conditions. "We speculated that you might not see a trend in the intensity of typical hurricanes due to environmental factors, but if the heat-engine theory is correct, you should see a trend in the intensity of hurricanes at or near their MPI," Elsner said. "On average, the strongest storms are closest to their MPI." The researchers created a data set from satellite observations of hurricane intensity of all tropical cyclones around the globe and looked at the maximum wind speeds for each one during a 25-year period. Tropical cyclones, which include hurricanes, typhoons and tropical storms, occur on average about 90 times per year worldwide. The researchers found that the strongest tropical cyclones are getting stronger, particularly over the North Atlantic and Indian oceans. Wind speeds for the strongest tropical storms increased from an average of 140 mph in 1981 to 156 mph in 2006, while the ocean temperature, averaged globally over the all regions where tropical cyclones form, increased from 28.2 degrees Celsius to 28.5 degrees Celsius during this period. "By creating a better, more consistent historical data set, we've been able to weed out quality issues that introduce a lot of uncertainty," Kossin said. "Then, by looking only at the strongest tropical cyclones, where the relationship between storms and climate is most pronounced, we are able to observe the increasing trends in storm intensity that both the theory and models say should be there." While Elsner said the heat-engine theory might explain how tropical cyclones intensify given that everything else is the same, he noted, "We still do not have a complete understanding of why some cyclones intensify, sometimes quite rapidly, and others don't." Florida State University Science News and Science Current Events Tag Cloud This tag cloud is a visual representation of term frequencies of random science news topics with common terms grouped together and emphasized by their display size. Bisphenol A Sexual Abuse Knee Replacement Virus Chemistry Large Hadron Collider Supernovae Pre-eclampsia Algae Carbon Emissions Sepsis Terrorism Astrocytes Pandemic Fish Oil Combination Therapy Pheromone Greenhouse Gases Fungi Iron Deficiency DNA damage Quasars Enzymes Endometriosis Ozone
See More: Science News Tags | |||||||||||||||||||||
|
Related Hurricanes Current Events and Hurricanes News Articles Dry autumns and winters may lead to fewer tornadoes in the spring, says UGA researcher Global warming will likely mean more unpredictable weather, scientists say, and a new study by researchers at the University of Georgia pins down, possibly for the first time, how drought conditions in an area's fall and winter may effect tornado activity the following spring. New publication shows index insurance has potential to help manage climate risks and reduce poverty Climate has always presented a challenge to farmers, herders, fishermen and others whose livelihoods are closely linked to their environment, particularly those in poor areas of the world. Corals face 'a stormy future' As global warming whips up more powerful and frequent hurricanes and storms, the world's coral reefs face increased disruption to their ability to breed and recover from damage. Berkeley Lab Scientists Contribute to Major New Report Describing Climate Change Impacts on the U.S. Two researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), Evan Mills and Michael Wehner, contributed to the analysis of the effects of climate change on all regions of the United States, described in a major report released today by the multi-agency U.S. Global Change Research Program. NJIT expert advises on the do and don't of building in hurricane-prone areas Better building practices for structures in hurricane-prone regions will be the focus of a paper next month in Caribbean Construction Magazine by NJIT architecture professor Rima Taher, PhD. In the turf war against seaweed, coral reefs more resilient than expected There's little doubt that coral reefs the world over face threats on many fronts: pollution, diseases, destructive fishing practices and warming oceans. Lesson from the past for surviving climate change Research led by the University of Leicester suggests people today and in future generations should look to the past in order to mitigate the worst effects of climate change. Yale study: Most polluted ecosystems recoverable Most polluted or damaged ecosystems worldwide can recover within a lifetime if societies commit to their cleanup or restoration, according to an analysis of 240 independent studies by researchers at the Yale School of Forestry & Environmental Studies. Researchers study the human factor in spread of pandemic illness Industrial engineers Sandra Garrett of Clemson University and Barrett Caldwell of Purdue University have proposed a new system to warn of an impending pandemic by monitoring signals in human behavior. Indigenous peoples at world summit to share climate change observations, coping techniques With the first climate change-related relocation of an Inuit village already underway, some 400 Indigenous People and observers from 80 nations are convening in Alaska for a UN-affiliated conference April 20-24 to discuss ways in which traditional knowledge can be used to both mitigate and adapt to climate change. More Hurricanes Current Events and Hurricanes News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||