The number of Atlantic hurricanes in an average season has doubled in the last century because of climate change, according to a new study.
The study, released July 29, said there is a correlation between an increasing number of tropical storms and hurricanes in the last 100 years and a 1.3-degree Fahrenheit increase in sea surface temperatures. The study was published online in Philosophical Transactions of the Royal Society of London.
Greg Holland of the National Center for Atmospheric Research and Peter Webster of the Georgia Institute of Technology conducted the hurricane study. Researchers found three periods since 1900 when the average number of Atlantic hurricanes significantly increased and then became steady again.
According to the study, Atlantic hurricane seasons had six storms on average annually from 1900 to 1930. From 1930 to 1940, the average rose to 10. The average then rose to 15 from 1995 to 2005.
Sea surface temperatures increased before the periods of increased storms, with a rise of .7 degrees Fahrenheit before the 1930 period and a similar increase before the 1995 period, the study stated.
"These numbers are a strong indication that climate change is a major factor in the increasing number of Atlantic hurricanes," Holland said.
The authors of the study note that skeptics say hurricane data from the early decades of the 20th century are not reliable because cyclones may have formed and died mid-ocean, where no one knew they existed. Later, more reliable data became available in 1944 when researchers had airplane observations and when satellites came into use in 1970. However, Holland and Webster said the improved data from the last 50 years should not be solely blamed for the increase.
"We are led to the confident conclusion," the authors wrote in the study, "that the recent upsurge in the tropical cyclone frequency is due in part to greenhouse warming, and this is most likely the dominant effect."
Evidence of more intense storms was prevalent in 2005. That year had 28 storms, 15 becoming hurricanes, including Katrina. The damage from those storms killed 1,500 people and cost $80 billion.
This year, the U.N. Intergovernmental Panel on Climate Change also released a report claiming that it was "more likely than not" that humans' contribution to global warming also adds to a trend of more dangerous hurricanes.
Mark Anderson, associate professor of geosciences at the University of Nebraska-Lincoln, said the chance for more hurricanes could have devastating consequences for the modern world.
"More people are on the coast now," he said. "A lot of hurricanes used to hit places people didn't live. Now, hitting a big city is a bigger prospect."
However, Anderson said, satellite technology does allow scientists to warn people better.
Anderson said people attempting to protect themselves from hurricanes could do so by staying out of danger zones. He also said hurricane clips could help a home withstand a hurricane. A hurricane clip ties the rafters to the roof of the home, helping the place stay together during a storm. Anderson said a home could probably be outfitted completely with hurricane clips for less than $100.
"I don't think we can do much to prevent a hurricane," he said. "But we can make people more aware. I know it makes a difference."
