Global warming leads to more 'Katrina' sized hurricanes: study

2013-03-21 03:19:55 GMT2013-03-21 11:19:55(Beijing Time)

Global warming leads to more 'Katrina' sized hurricanes, according to a study by GCESS, BNU. (Photo/Agencies)

File photo of 'katrina' (Photo/Agencies)

By Xiong Yuqing

Atlantic coastal cities should pay more attention to disaster prevention from hurricanes, as global warming is likely to bring more frequent storms in coming years, according to a recent study by Beijing Normal University (BNU).

Temperature linked to hurricanes

Three scientists from the College of Global Change and Earth System Science(GCESS), BNU, published a report on Proceedings of the National Academy of Sciences (PNAS), in which they claimed to have found a strong connection between coastal flood surges and surface temperature, which could be used to see how the hurricanes' frequency changes.

They studied hurricane records by tide gauges stations since 1920s, examining the local temperatures and combining them into a model for predicting hurricane size and frequency.

"We tried many teleconnection patterns, and none of them gave us a good fit as temperature, including global temperature and the temperature of the sea, the tropical Atlantic, where the hurricanes form. It shows that temperature is by far the best predictor," said John Moore, the chief scientist of GCESS.

"The really important thing is that the stronger the storm surge, the more likely it links to increased temperature. And that is what becomes big event and causes most damage." he added.

In 2005 Hurricane 'Katrina' caused great damage to New Orleans. As the temperature rise has been continuing since 1923 due to the greenhouse gas and human activities, 'Katrina' was more likely caused by global warming other than a random case, according to John's study.

Global warming puts coastal cities in danger

The report indicates that chance of storm surges of such magnitude increases 10 times if the average global temperature is 2C higher, which means that there will be a 'Katrina' magnitude storm surge every other year.

"We find that 0.4 degree Celsius warming of the climate corresponds to a doubling of the frequency of extreme storm surges like the one following Hurricane Katrina," said the report. Global warming is bringing much more 'Katrina's to coastal areas.

Not only the increasing frequency of hurricanes will hit the coastal cities, the growing sea levels due to the melting polar glaciers, which are also caused by global warming, will also strengthen the surge index and put the cities in danger.

"When planning a bridge or a building in a city, people usually assume that the return frequency is constant, which we found exactly not the case. The probability distribution of 'Katrina's changes a lot. It means that it will be far more dangerous to set something like nuclear power station in Atlantic coastal cities, because they will face high risk of damage by hurricanes and surge flood," John told Sina English.

He said:" Of course the damage the storm surge actually does depends on exactly where the hurricane happens to land – and our model can’t predict that, only statistical likelihoods. But the global warming we have already had over the 20th century, means we crossed the threshold where more than half of all ‘Katrina’ sized storm surges are due to global warming."