|DOES GLOBAL WARMING|
PRODUCE STRONGER HURRICANES?
METEOROLOGIST JEFF HABY
Global warming is a widely debated topic in earth science. The earth over the past millions of
years has gone through stages of warming and cooling. Those stages were not caused by humans
since it predates human's exponential population growth. Those stages were likely caused by a
combination of changes in solar output, changes in earth
albedo, meteor impacts, changes in
earth-sun distance, changes in tilt of earth, changes in time of year earth is closest to sun, changes
in position of earth's plates, changes in biology on earth, feedback mechanisms, changes in
oceanic salinity, volcanic eruptions, and changes in amount and abundance of atmospheric gasses.
While gradual and abrupt changes mentioned above have occurred and are occurring today
in earth's history, the human influence is now creating
change also. Many of these human induced changes in theory help warm the earth. These changes include
the emission of longwave trapping greenhouse gases and decreasing vegetation cover. It is debatable
how much warming is natural and how much is human enduced. There is evidence that
warming is occurring recently and today due to the rising sea level produced from
glacier and ice cap melting.
One of the ingredients required for
hurricane development and for a hurricane to sustain itself is
warm ocean water. All else being equal, warmer ocean sea surface temperatures should produce
a stronger hurricane. Evidence for this is the rapid intensification a tropical system will
undergo as it moves over a warmer pool of ocean water and the sudden weakening
that can take place when it moves over colder water.
Sea surface temperatures cycles that are not completely understood. One of the more understood
and discussed cycles is the El Nino / La Nina in the eastern Pacific. There are factors
that could be responsible for these sea surface temperature cycles including ocean currents,
weather patterns and cycles of salinity and temperature changes within deep sea ocean waters. Some ocean
temperature cycles seem to repeat every few years but other cycles may last for decades.
While global warming can warm the ocean sea surface temperatures there are other oceanic
and atmospheric cycles that could be much more important in contributing to stronger and more frequent
hurricanes in a particular year. The record number of tropical systems and intense hurricanes
during the 2005 Atlantic hurricane season spotlighted this issue.