Storm-surge records show significant connection to climate change

Ars Technica : Last year Aslak Grinsted of the University of Copenhagen and his colleagues used the historical record of storm surges to show a correlation between climate change and the frequency and size of hurricanes. Now, having examined storm-surge records dating back to 1923, they have discerned a clearer relationship between global warming and storm severity. By controlling for sea-level changes and comparing the surge data to contributing factors, they found the highest correlation between surge levels and a combination of global average temperatures and sea-surface temperatures in the areas where hurricanes formed. Using that data, the researchers created a model of hurricane behavior, which showed that a 1-°C global average temperature rise increased the likelihood of a storm surge the size of Hurricane Katrina’s by two to seven times. Grinsted’s team believes that because of global warming, storm surges of that size are now twice as likely to occur as they were 90 years ago. And when sea-level rise is taken into consideration, they also cause more damage.