The devastation in the gulf coast left by hurricanes Katrina and
Rita has many people hoping that President Bush will now be
convinced by scientific evidence that global warming is a powerful
force affecting our nation, and will prompt him to sign
international treaties to reduce U.S. greenhouse gas emissions.
Scientists nationwide have recently compiled evidence suggesting
the intensity and frequency of hurricanes are related to global
warming. Bush and his administration have consistently rebuffed any
notion that such a link exists.
Several studies recently published by the Massachusetts
Institute of Technology and Georgia Tech’s School of Earth
and Atmospheric Sciences show that there is a significant
statistical relationship between the number of Category 4 and 5
hurricanes in the past few decades and the overall rising
temperature of the ocean.
“The net hurricane power dissipation is highly correlated
with tropical sea surface temperature, reflecting well-documented
climate signals, including … global warming,” said Kerry
Emanuel, global warming researcher at MIT, in his article
“Increasing destructiveness of Tropical Cyclones Over The
Past 30 Years,” which was published in the Aug. 4 issue of
Nature.
This study is the latest from research collected by Emanuel, who
has been publishing research about the link between global warming
and hurricanes since the late 1980s.
In his most recent article, Emanuel said that while factors
contributing to global warming continue to go unchecked, their
relationship between the long-ranging damage that happens from
powerful hurricanes cannot continue to be ignored.
A study completed in July at Georgia Tech supports
Emanuel’s conclusions. Peter Webster, professor at Georgia
Tech’s School of Earth and Atmospheric Sciences, and Greg
Holland of The National Center for Atmospheric Research studied the
change in hurricane patterns as the global sea surface temperatures
have increased since the 1970s. They also noted the number of
Category 4 and 5 hurricanes worldwide has nearly doubled during the
past 35 years, while the total number of hurricanes has dropped
since the 1990s.
Hurricanes are caused when warm temperatures and humid air
increase the energy of a low-intensity tropical storm, making it
dangerous. Powerful Category 4 hurricanes have winds around 140
miles per hour; while Category 5 systems, such as Hurricane Katrina
at its peak over the Gulf of Mexico, had winds of 156 mph or more,
according to the National Atmospheric Research Web site.
Tropical storms generally occur in late summer and fall, when
the oceans near the U.S. are at their warmest. Storms that stay
over the ocean increase in power and energy but only pose a problem
for ships. When a hurricane moves onto land, however, it will lose
the energy from the oceanic tropical moisture, which fuels the
storm and causes the devastating damage.
Hurricane Katrina, for example, increased in energy while it
crossed the warm waters of the Gulf of Mexico from Florida to
Louisiana and Mississippi. The magnitude of destruction so far from
the coast, including in New Orleans, is a result of the long time
it took the storm to lose energy over land where it lacks the warm
ocean water.
“To have hurricanes develop you need warm oceans, which is
why they are common in the tropics where the warmer temperatures
aid the evaporation in the air which can lead to hurricane
circumstances,” said James Murakami, UCLA staff
meteorologist.
Despite the destruction these storms are capable of causing,
most people believe the economists who project that it would be too
much of an economic burden to fully fund research and fight global
warming, said Bjorn Stevens, UCLA associate professor in
atmospheric and oceanic sciences.
Stevens is offering a seminar this quarter to specifically
address the causes and effects of hurricanes, and hopes to also
address some of the political fallout after Katrina and Rita.
The most potent arguments against United States participation in
the Kyoto Protocol come from businesses whose economists project
that the economy would be significantly damaged both in the form of
profits and workers’ jobs.
However, scientists and activists still wait to see if these new
studies combined with the losses caused by Katrina and Rita will be
enough to change Bush’s mind about the United States’
approach toward global warming.
The most logical step, according to Stevens, would be for Bush
to sign the Kyoto Protocol, which would commit businesses to reduce
their carbon dioxide emissions to 1990 levels.
The U.S., which emits 25 percent of the world’s greenhouse
gasses, has yet to sign the international treaty, weakening its
overall effectiveness.
“Countries around the world have governments instating
stricter regulations, but without larger countries like the United
States participating, there will only be minimal difference in
overall carbon dioxide emissions,” Murakami said.
These scientific methods run in direct conflict with economists
who fear trying to fix global warming would cost the U.S. in time,
money and economic power.
“It will cost a lot of money to make a difference in
global warming,” said Stevens, “It seems the scientists
have always had a higher burden of proof. To me, the
economists’ science seems weaker.”