Stronger, more frequent hurricanes ahead?
Hurricane Rita. September 21, 2005 (NOAA)
Dan Kulpinski reports for Earth & Sky from Washington D.C., on the latest scientific results related to hurricanes and climate change.
(September 23, 2007) Hurricane scientists gathered in Washington D.C. Friday to present recent results and ponder the ongoing debate about whether hurricanes will become stronger and/or more frequent, as Earth warms in the 21st century.
They noted that hurricane activity in the decades ahead may be very different from what we have seen in past decades. But different in what way? The answer is still unclear.
Since the 1980s, hurricane activity in the Atlantic has risen and hurricane intensity appears to have more than doubled. Some models have indicated a link between stronger hurricanes and climate change, while others have disagreed.
The handful of hurricane modelers gathered in the the Dirksen Senate Office Building on Capitol Hill Friday did not resolve the controversy.
There was general agreement in the room that hurricanes probably would get stronger over the next century, but disagreement remained over whether or not we would see more hurricanes in the Atlantic or fewer. And this group did seem to agree on one point: the future for hurricane activity looks very different from the last five decades. That was one of the key points made at the September 21 seminar at titled ‘Hurricanes and Climate Change: What’s Resolved and What Remains to Be Resolved?’ The American Meteorological Society organized the event.
Kerry Emanuel, who was one of the presenters at the seminar, said the latest computer climate models “predict far less change than we have seen over the last 50 years.”
“There’s a big inconsistency,” he said. “There’s a lot to be done.”
It is “important to understand that the community of scientists working on hurricanes is a pretty tiny number when you compare to, say, scientists working on earthquakes,” said Emanuel. “There just aren’t a lot of us working in this field. Our big worry … is the number of scientists working on this.”
Dr. Gabriel Vecchi, a research oceanographer at NOAA’s Geophysical Fluid Dynamics Lab in Princeton, N.J., said his models show that although the intensity of tropical storms in the northern hemisphere could increase this century, “overall the wind shear effect may make the North Atlantic and East Pacific more hostile to hurricanes.”
He said statistical estimates “point at larger potential change in the Western Pacific and Indian Ocean” in terms of increase in the number of hurricanes.
Dr. Greg Holland of the National Center for Atmospheric Research in Boulder, Colorado seemed to disagree with the models indicating less Atlantic hurricane activity, citing a “massive expansion of the warm pool” in the Atlantic basin, where hurricanes form. He also noted that the hurricane season appears to be getting longer each year. The “warm pool” and longer season for hurricanes maybe be two factors that could keep hurricane activity on the increase.
He also said, “While there is an oscillation in the proportions of major hurricanes, the number of major hurricanes has increased substantially in accord with the overall increase in frequency.”
Several participants noted that rainfall from hurricanes is projected to increase some 12 percent over the next 100 years.
Dr. William Lau, chief of the Laboratory of Atmospheres at NASA’s Goddard Space Flight Center, discussed how dust and dry air from the Sahara Desert may suppress hurricane formation.
Thomas Knutson, a research meteorologist at the NOAA Geophysical Fluid Dynamics Lab, described a promising new computer modeling technique that focuses in high-resolution on the North Atlantic. This “regional downscale model” looks at a region in higher detail than the global climate models can. Even this scaled-down approach requires 100 computer processors running simultaneously. Knutson said the model can generate an entire season of hurricanes. He used it “to simulate what has happened in the past, from 1980 forward through 2006. We can reproduce fairly accurately what has happened.”
Such a model could allow Knutson to more accurately predict future hurricane seasons based on climate change scenarios.
Meanwhile, the uncertainty about hurricane activity in the years ahead continues.
Because hurricanes can have a devastating effect on the lives and property of people living near coasts, these scientists noted that they could use more resources and more hurricane scientists to help advance scientific knowledge about the relationship between climate change and hurricanes.
I am surprised “The Real Experts”, the global warming people did not get quoated. The news media is quick to quote them everytime one forms and is strong.
Lot to be done because these researchers do not have electrics in their kens.