|
In another sign of global warming's growing influence on weather
patterns around the world, a team of climate scientists have found that
the number of storms in the Atlantic has dramatically increased over
the past century.
They attribute this upswing — a doubling in the average number of
yearly storms since 1905 — to a rise in sea surface temperatures in the
Atlantic (0.7°C over the past century).
Greg Holland, a climate scientist of the US National Center for
Atmospheric Research in Boulder, Colorado, and one the lead authors on
the study with Georgia Institute of Technology's Peter Webster,
identified three separate climate regimes in the last century: the
first, extending from 1905 to 1930, had an average of 6 storms each
year (4 of which were hurricanes); the second, from 1931 to 1994, had a
higher average of 10 storms (5 of which were hurricanes); the third,
from 1995 to 2005, had a record average of 15 annual storms (8 of which
were hurricanes). Holland and his colleagues believe this average
number could still rise further within this century.
While the ratio of hurricanes to all Atlantic tropical cyclones has
remained mostly unchanged over the last few decades — accounting for
close to 55% of all cyclones — the ratio of major hurricanes (with
maximum sustained winds of at least 110 mph) to weaker hurricanes and
storms has risen significantly in recent years.
Though there remain some prominent detractors, notably Colorado
State University's meteorologist William Gray, climate science is
slowly but surely moving towards a new consensus in the
hurricane-climate debate, with global warming being increasingly blamed
for some of the unprecedented weather patterns we've witnessed over the
last few years. Greg Holland, a former student of Gray's and once
global warming skeptic, has evidently changed his views quite a bit
since his graduate days.
|