|
Did global warming power Katrina?
Sept. 15, 2005
Special to World Science
http://www.world-science.net/othernews/050915_stormfrm.htm
In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes.
A study to be published tomorrow provides striking new evidence linking giant hurricanes such as Katrina—which devastated the Gulf of Mexico last month—to rising ocean temperatures, scientists say.
 |
 |
| Images of Katrina’s eyewall — the most powerful part of the storm, the area around the eye — as seen from an aircraft on Aug. 28, as the storm approached the U.S. Gulf Coast. ( U.S. National Oceanic & Atmospheric Administration) |
That, the researchers added, provides new reason to study whether global warming is making hurricanes stronger, as some suspect.
The evidence to date, while intriguing, doesn’t prove the case, scientists said. This is partly because studies so far include only a few decades’ worth of data, which isn’t enough.
It’s also because scientists lack a detailed explanation of how global warming would cause the hurricane trends seen so far. For instance, hurricanes are getting stronger, but not more frequent, and scientists don’t know why.
In general, it makes sense that higher temperatures would boost hurricane strength, many scientists say. Heat is energy, and energy drives hurricanes.
The study, to appear tomorrow in the research journal Science, is at least the second to link stronger hurricanes with rising temperatures.
The link is statistical: as temperatures have risen, hurricanes have become more violent, the researchers said. Whether the first causes the second remains unproven.
“What we found was rather astonishing,” said Peter Webster of the Georgia Institute of Technology in Atlanta, Ga., lead author of the study.
“In the 1970’s, there was an average of about 10 Category 4 and 5 hurricanes per year globally. Since 1990, the number of Category 4 and 5 hurricanes has almost doubled, averaging 18 per year globally.”
Category 4 hurricanes have sustained winds from 131 to 155 miles per hour; Category 5 systems, such as Hurricane Katrina at its peak over the Gulf of Mexico, feature winds of 156 mph or more.
Katrina slammed its full force against the country blamed most widely for global warming—the United States. The warming is believed to be caused by increasing atmospheric levels of carbon dioxide a byproduct of human burning of fossil fuels such as coal and petroleum. The gases trap heat in the atmosphere.
“Category 4 and 5 hurricanes made up about 20 percent of all hurricanes in the 1970’s, but over the last decade they account for about 35 percent of these storms,” said Georgia Tech’s Judith Curry, a co-author of the study.
All this is happening as sea-surface temperatures are rising globally—from around one-half to one degree Fahrenheit, depending on the region, for hurricane seasons since the 1970s, the researchers said.
“Our work is consistent with the concept that there is a relationship between increasing sea surface temperature and hurricane intensity,” said Webster. “However, it’s not a simple relationship. In fact, it’s difficult to explain why the total number of hurricanes and their longevity has decreased during the last decade, when sea surface temperatures have risen the most.”
The only region that is experiencing more hurricanes overall is the North Atlantic, where they have become more numerous and longer-lasting, especially since 1995, Webster said.
The North Atlantic has averaged eight to nine hurricanes per year in the last decade, compared to the six to seven per year before the increase, the authors reported. Category 4 and 5 hurricanes in the North Atlantic have increased at an even faster clip: from 16 in the period of 1975-89 to 25 in the period of 1990-2004, a rise of 56 percent.
A study published in July in the journal Nature came to a similar conclusion. Focusing on North Atlantic and North Pacific hurricanes, Kerry Emanuel of the Massachusetts Institute of Technology in Cambridge, Mass. found an increase in their duration and power, although it used a different measurement to determine a storm’s power.
To prove whether human-induced warming is cause the trend will require “a longer data record of hurricane statistics,” Webster said. Also, “we need to understand more about the role hurricanes play in regulating the heat balance and circulation in the atmosphere and oceans.”
Computer simulations do show global warming would produce stronger hurricanes, researchers said.
The new findings “will stimulate further research” into both natural and human-driven processes influencing hurricane trends, said Jay Fein, director of climate and large scale dynamics program at the National Science Foundation in Arlington, Va., which funded the research.
Webster is studying the role of hurricanes in climate.
“The thing they do more than anything is cool the oceans by evaporating the water and then redistributing the oceans’ tropical heat to higher latitudes,” he said. “But we don’t know a lot about how evaporation from the oceans’ surface works when the winds get up to around 100 miles per hour, as they do in hurricanes.” Understanding this is key to learning whether global warming is fueling hurricanes, he added.
“If we can understand why the world sees about 85 named storms a year and not, for example, 200 or 25, then we might be able to say that what we’re seeing is consistent with what we’d expect in a global warming scenario. Without this understanding, a forecast of the number and intensity of tropical storms in a future warmer world would be merely statistical extrapolation.”
[Thanks for the DVD players. Now how about a future? – JAH]
Displaced oil workers get new homes
http://www.cnn.com/2005/US/09/15/katrina.sugarville.reut/index.html
In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes.
ST. JAMES, Louisiana (Reuters) -- Compared with many others forced from their homes by Hurricane Katrina, residents of Sugarville have comfortable new houses, complete with amenities like soft beds, DVD players and full refrigerators.
Of course, "Sugarville" is actually a huge dirt lot on the grounds of the Royal Dutch Shell Sugarland Terminal in this southeastern Louisiana town.
The "houses" are Fleetwood Enterprises trailers supplied by the Federal Emergency Management Agency to house oil workers and their families displaced by the storm that devastated the U.S. Gulf Coast.
But for at least 75 people, it is home for possibly up to six months as the region tries to rebuild after the August 29 storm laid waste to communities like St. Bernard, Orleans and Plaquemines parishes. But the recovery effort is being balanced by the needs of commerce, particularly the hungry energy market.
"Is it different? Absolutely. It's out of the norm, but our facilities are up and running," said Doug Schexnayder, operations support supervisor at the facility, which is about 60 miles from New Orleans and largely escaped Katrina.
For those in the storm's path, there are complaints far and wide that disaster response officials are not moving fast enough to find housing for storm evacuees.
But when it comes to the oil industry, FEMA moved quickly, scrambling to get trailers so refineries could come back online and crude could begin flowing again.
The compound of 165 trailers will house displaced employees from the Convent and Norco refineries as well as Shell exploration and production staff from New Orleans.
The Sugarland terminal usually has about 40 people working on site, but spokesman Gary Miller said it could ultimately shelter up to 600 people until they get permanent housing.
State economic officials credit the energy companies for much of the initiative, since a displaced workforce means production grinds to a halt.
"The larger corporations have such significant resources, they take their initiative and move forward without significant needs," said Don Pierson, assistant secretary of the state Department of Economic Development.
Shell says it is trying to give people some of the comforts of home, including laundry service, three hot meals a day and a playground for the children -- in the shadow of tanks that hold up to 300,000 barrels of crude for the nation's Strategic Petroleum Reserve.
The community appeared largely uninhabited during a media tour Thursday, but construction crews were digging trenches and laying pipe for sewer and electrical services, and cleaning crews were making up beds in the trailers, which can each sleep as many as six people.
After communities are rebuilt and the residents of "Sugarville" move on, the infrastructure that supported them will become a permanent feature of the Sugarland terminal.
"We'll leave it in place in case this happens again," Schexnayder said.
Copyright 2005 Reuters. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
Please Note
This function has been disabled.
|
|
|
|
Did global warming power Katrina?