Global warming is causing stronger Atlantic hurricanes finds new study
Rhett A. Butler, mongabay.com
March 1, 2007
Previously the hurricane database was considered inconsistent for measuring the record of tropical storms since there have been significant improvements in the technology to measure storms since recording-keeping began. Before the development of weather satellites, scientists relied on ship reports and sailor logs to record storms. The advent of weather satellites in the 1960s improved monitoring, but records from newer technology have never been squared with older data. The new study "normalizes" the hurricane record since 1983.
"The debate is not about scientific methods, but instead centers around the quality of hurricane data," said lead author James Kossin, a research scientist at UW-Madison's Cooperative Institute for Meteorological Satellite Studies. "So we thought, 'Lets take the first step toward resolving this debate.'"
Warm ocean waters fuel hurricanes, and there was plenty of warm water for Katrina to build up strength once she crossed over Florida and moved into the Gulf of Mexico. This image depicts a 3-day average of actual sea surface temperatures (SSTs) for the Caribbean Sea and the Atlantic Ocean, from August 25-27, 2005. Every area in yellow, orange or red represents 82 degrees Fahrenheit or above. A hurricane needs SSTs at 82 degrees or warmer to strengthen. The data came from the Advanced Microwave Scanning Radiometer (AMSR-E) instrument on NASA's Aqua satellite. The GOES satellite provided the cloud data for this image. Image Credit: NASA/SVS.
Kossin and co-authors Daniel Vimont, a UW-Madison atmospheric scientist, Ken Knapp, a scientist at the NCDC, and Richard Murnane, a scientist at the Bermuda Institute of Ocean Sciences, used the new dataset to assess two controversial studies (published in Nature and Science) that argued climate change is causing more frequent and intense hurricanes.
The authors found that the conclusions hold for the Atlantic but not other parts of the world.
"The data says that the Atlantic has been trending upwards in hurricane intensity quite a bit, but the trends appear to be inflated or spurious everywhere else, meaning that we still can't make any global statements," said Kossin. "The average conditions in the Atlantic at any given time are just on the cusp of what it takes for a hurricane to form. So it might be that imposing only a small (man-made) change in conditions, creates a much better chance of having a hurricane."
Hurricanes require temperatures of around 27 degrees Celsius (81 degrees Fahrenheit) to develop. Because the Atlantic Ocean is cooler than other areas where hurricanes (known as typhoons in the Western Pacific and cyclones elsewhere) form, it is more susceptible to small changes in ocean temperature say the researchers.
While the new research has normalized the satellite-based hurricane records, other scientists are working to develop alternative ways to measure historic hurricanes including tropical caves and tree rings
Caves may reveal if global warming is causing stronger hurricanes -- 1/29/2007
Scientists have shown that cave formations could help settle the contentious debate on whether hurricanes are strengthening in intensity due to global warming. Measuring oxygen isotope variation in stalagmites in Actun Tunichil Muknal cave in central Belize, a team of researchers have identified evidence of rainfall from 11 tropical cyclones over a 23 year period (1978-2001). The research -- the study of ancient storms is called paleotempestology -- could help create a record of hurricanes that would help researchers understand hurricane frequency and intensity. "Tropical cyclones (including hurricanes, tropical storms, typhoons, and cyclones) produce rainwater that is different from other summertime precipitation," explained Amy Benoit Frappier, an assistant professor in the Department of Geology and Geophysics at Boston College and lead author of the study published in Geology. "Tropical cyclones produce isotopically light rainwater primarily because 1) their cloud tops are very high and cold, and 2) their humid air tends to prevent lighter water molecules from evaporating back out of the raindrop as they fall."
Tree rings could settle global warming hurricane debate -- 9/20/2006
Scientists have shown that ancient tree rings could help settle the debate as to whether hurricanes are strengthening in intensity due to global warming. By measuring different isotopes of oxygen present in the rings, Professors Claudia Mora and Henri Grissino-Mayer of the University of Tennessee have identified periods when hurricanes hit areas of the Southeastern United States up to 500 years ago. The research could help create a record of hurricanes that would help researchers understand hurricane frequency and intensity. Currently reliable history for hurricanes only dates back a generation or so. Prior to that, the official hurricane records kept by the National Oceanic and Atmospheric Administration's Atlantic basin hurricane database (HURDAT) are controversial at best since storm data from more than 20 years ago is not nearly as accurate as current hurricane data due to improvements in tracking technology. The lack of a credible baseline makes it nearly impossible to accurately compare storm frequency and strength over the period.
ARTICLES ON THE LINK BETWEEN GLOBAL WARMING AND HURRICANES
Hurricane intensity linked to global warming -- 8/15/2006
A new study says climate change is affecting the intensity of Atlantic hurricanes and that hurricane damage will likely worsen in coming years due to increasing ocean temperatures. Unlike recent studies that have linked higher sea temperatures to an increase in the number of hurricanes, the new research shows a direct relationship between climate change and hurricane intensity.
Global Warming Fueled Record 2005 Hurricane Season Conclude Scientists -- 6/22/2006
Global warming accounted for around half of the extra hurricane-fueling warmth in the waters of the tropical North Atlantic in 2005, while natural cycles were only a minor factor, according to a new analysis by Kevin Trenberth and Dennis Shea of the National Center for Atmospheric Research (NCAR). The study will appear in the June 27 issue of Geophysical Research Letters, published by the American Geophysical Union
Study questions link between hurricanes and global warming -- 5/10/2006
New research calls into question the linkage between major Atlantic hurricanes and global warming. That is one of the conclusions from a University of Virginia study to appear in the May 10, 2006 issue of the journal Geophysical Research Letters. In recent years, a large number of severe Atlantic hurricanes have fueled a debate as to whether global warming is responsible. Because high sea-surface temperatures fuel tropical cyclones, this linkage seems logical. In fact, within the past year, several hurricane researchers have correlated basin-wide warming trends with increasing hurricane severity and have implicated a greenhouse-warming cause.
Birthplace of hurricanes heating up say NOAA scientists -- 5/3/2006
The region of the tropical Atlantic where many hurricanes originate has warmed by several tenths of a degree Celsius over the 20th century, and new climate model simulations suggest that human activity, such as increasing greenhouse gas emissions into the atmosphere, may contribute significantly to this warming. This new finding is one of several conclusions reported in a study by scientists at the NOAA Geophysical Fluid Dynamics Laboratory in Princeton, N.J., published today in the Journal of Climate.
US denies hurricane link with climate change -- 12/1/2005
Harlan Watson, chief climate control negotiator for the U.S. State Department, told the Associated Press that the Bush administration does not blame global warming or climate change for extreme weather -- including the hurricanes that thrashed the Gulf earlier this year.
Hurricane Katrina damage just a dose of what's to come -- 9/21/2005
The kind of devastation seen on the Gulf Coast from Hurricane Katrina may be a small taste of what is to come if emissions of the greenhouse gas carbon dioxide (CO2 ) are not diminished soon, warns Dr. Ken Caldeira of the Carnegie Institution's Department of Global Ecology in his opening remarks at the 7th International Carbon Dioxide Conference in Boulder, Colorado, September 26, 2005.
Number of Category 4 and 5 hurricanes has nearly doubled over past 35 years -- 9/16/2005
The number of Category 4 and 5 hurricanes worldwide has nearly doubled over the past 35 years, even though the total number of hurricanes has dropped since the 1990s, according to a study by researchers at the Georgia Institute of Technology and the National Center for Atmospheric Research (NCAR). The shift occurred as global sea surface temperatures have increased over the same period. The research appears in the September 16 issue of Science.
Hurricane could hit San Diego -- 9/8/2005
San Diego has been hit by hurricanes in the past and may be affected by such storms in the future according to data from the National Oceanic and Atmospheric Administration (NOAA). While a hurricane in San Diego would likely produce significantly less damage that Hurricane Katrina in New Orleans, it could still exact a high cost to Southern California especially if the region was caught off guard.
Hurricanes getting stronger due to global warming says study -- 8/29/2005
Late last month an atmospheric scientist at Massachusetts Institute of Technology released a study in Nature that found hurricanes have grown significantly more powerful and destructive over the past three decades. Kerry Emanuel, the author of the study, warns that since hurricanes depend on warm water to form and build, global climate change might increase the effect of hurricanes still further in coming years.
This article used quotes and information from a University of Wisconsin-Madison news release