| on May 19, 2008, 11:59 AM E.S.T.
|
 Global warming is not to blame for the recent jump in hurricanes, according to a top scientist who previously warned about the meteorological impact of climate change.
Rising temperatures may actually reduce the number of hurricanes in the
Atlantic, Tom Knutson claims in a new study.
Dr Knutson’s change of heart has reignited the debate in the US about how
closely hurricanes can be tied to global warming.
Since Hurricane Katrina devastated New Orleans in 2005, environmentalists and
some scientists have seized on hurricanes as symbols of the damaging
consequences of climate change.
Other scientists assert that the recent rise in hurricanes in the Atlantic
that was first noted in the 1980s is unrelated to climate change and rising
sea temperatures.
Dr Knutson’s study, which is based on computer models, predicts that
hurricanes will become less common, but more destructive, by the end of this
century.
They are also likely to be accompanied by much heavier downpours of rain.
Dr Knutson and colleagues from the National Oceanic & Atmospheric
Administration (NOAA) at Princeton, New Jersey, ran computer replays of each
August to October hurricane season between 1980 and 2006.
The simulations were then repeated to show what would happen if ocean and
atmospheric conditions were altered by expected levels of global warming.
The "warm climate" runs generated 27 per cent fewer tropical storms and 18 per
cent fewer hurricanes.
The team concluded that the recent jump in hurricane frequency was caused not
by high temperatures in the Atlantic, but by differences in temperatures
between oceans.
Uniform warming of all ocean basins does not generate more hurricanes, they
found.
Dr Knutson’s methods have been criticised by other hurricane experts. Kerry
Emanuel of the Massachusetts Institute of Technology said his computer model
was flawed and his conclusions "demonstrably wrong".
Kevin Trenberth, a climate scientist, said Dr Knutson's model was poor at
assessing tropical weather and "failed to replicate storms with any kind of
fidelity”.
Dr Knutson's report was published online in the journal Nature Geoscience. Source
|
