Twice as many Atlantic hurricanes formed each year from 1995 to 2005, on average, than formed during parallel years a century ago finds a new statistical analysis of hurricanes and tropical storms in the north Atlantic. The researchers conclude that warmer sea surface temperatures and altered wind patterns associated with global climate change are responsible for the increase.
Hurricane hunters flew into and around the eye of Hurricane Katrina. August 28, 2005. (Photo courtesy NOAA) The study, by Greg Holland of the National Center for Atmospheric Research, NCAR, and Peter Webster of Georgia Institute of Technology, is published online today by the Royal Society of London.
"These numbers are a strong indication that climate change is a major factor in the increasing number of Atlantic hurricanes," says Holland.
For the 2007 Atlantic hurricane season, NOAA scientists predict 13 to 17 named storms, with seven to 10 becoming hurricanes, of which three to five could become major hurricanes of Category 3 strength or higher. An average Atlantic hurricane season brings 11 named storms, with six becoming hurricanes, including two major hurricanes.
The analysis by Holland and Webster identifies three periods since 1900, separated by sharp transitions, during which the average number of hurricanes and tropical storms increased and then remained elevated and relatively steady.
The first period, between 1900 and 1930, saw an average of six Atlantic tropical cyclones each year, of which four were hurricanes and two were tropical storms.
From 1930 to 1940, the annual average increased to 10, consisting of five hurricanes and five tropical storms.
In the final study period, from 1995 to 2005, the average reached 15, of which eight were hurricanes and seven were tropical storms.
This last period has not yet stabilized, which means that the average hurricane season may be even more active in the future.
Holland and Webster say it is not possible at this time to predict the level at which the frequency and intensity of storms will stabilize.
Hurricane hunters flew into and around the eye of Hurricane Katrina. August 28, 2005. (Photo courtesy NOAA) The study, by Greg Holland of the National Center for Atmospheric Research, NCAR, and Peter Webster of Georgia Institute of Technology, is published online today by the Royal Society of London.
"These numbers are a strong indication that climate change is a major factor in the increasing number of Atlantic hurricanes," says Holland.
For the 2007 Atlantic hurricane season, NOAA scientists predict 13 to 17 named storms, with seven to 10 becoming hurricanes, of which three to five could become major hurricanes of Category 3 strength or higher. An average Atlantic hurricane season brings 11 named storms, with six becoming hurricanes, including two major hurricanes.
The analysis by Holland and Webster identifies three periods since 1900, separated by sharp transitions, during which the average number of hurricanes and tropical storms increased and then remained elevated and relatively steady.
The first period, between 1900 and 1930, saw an average of six Atlantic tropical cyclones each year, of which four were hurricanes and two were tropical storms.
From 1930 to 1940, the annual average increased to 10, consisting of five hurricanes and five tropical storms.
In the final study period, from 1995 to 2005, the average reached 15, of which eight were hurricanes and seven were tropical storms.
This last period has not yet stabilized, which means that the average hurricane season may be even more active in the future.
Holland and Webster say it is not possible at this time to predict the level at which the frequency and intensity of storms will stabilize.
Interfaith Power and Light is a religious response to global warming with chapters in 22 states and Greater Washington, D.C. Find a link to your local chapter at http://www.theregenerationproject.org/State.htm