Scientist: “With the global warming we have had during the 20th century, we have already crossed the threshold where more than half of all ‘Katrinas’ are due to global warming.”
By Aslak Grinsted via the Nils Bohr Institute.
By examining the frequency of extreme storm surges in the past, previous research has shown that there was an increasing tendency for storm hurricane surges when the climate was warmer. But how much worse will it get as temperatures rise in the future? How many extreme storm surges like that from Hurricane Katrina, which hit the U.S. coast in 2005, will there be as a result of global warming? New research from the Niels Bohr Institute show that there will be a tenfold increase in frequency if the climate becomes two degrees Celcius warmer. The results are published in the scientific journal, Proceedings of the National Academy of Science, PNAS.
The extreme storm surge from Superstorm Sandy in the autumn 2012 flooded large sections of New York and other coastal cities in the region – here you see Marblehead, Massachusetts. New research shows that such hurricane surges will become more frequent in a warmer climate.
Tropical cyclones arise over warm ocean surfaces with strong evaporation and warming of the air. The typically form in the Atlantic Ocean and move towards the U.S. East Coast and the Gulf of Mexico. If you want to try to calculate the frequency of tropical cyclones in a future with a warmer global climate, researchers have developed various models. One is based on the regional sea temperatures, while another is based on differences between the regional sea temperatures and the average temperatures in the tropical oceans. There is considerable disagreement among researchers about which is best.
New model for predicting cyclones
“Instead of choosing between the two methods, I have chosen to use temperatures from all around the world and combine them into a single model,” explains climate scientist Aslak Grinsted, Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.