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Warmer oceans, larger hurricanes would add to coastal property risks


If the oceans continue to warm at a predicted rate, financial losses caused by hurricanes could increase more than 70% by 2100, according to a recent study.

The study, co-authored by David Rosowsky, a civil engineer at the University of Vermont in Burlington and the university’s provost and senior vice president, said the calculation is based on warming trends predicted by the Intergovernmental Panel on Climate Change, a United Nation-sponsored group that assesses climate change research. 

“The heat in the ocean is the fuel for these storms,” Mr. Rosowsky said, “what causes these things to strengthen is warmth.”

The study did not find that warming oceans will lead to more frequent hurricanes, he said, only that warmer seas will lead to higher wind speeds and storms that are greater in size, and therefore cover a larger area.

“What we’re finding … is that the storms are getting bigger,” Mr. Rosowsky said. “It’s less that we’re seeing a big increase in frequency, it’s just that these storms are more intense, which means they have higher peak wind speeds and they’re larger, which means they cover larger areas. So you can appreciate as we look at more, larger storms, we have more of the built infrastructure inventory is exposed and at risk.”

The losses are calculated based only on wind and wind-driven rain and do not include the large financial impacts of storm surge or flooding, according to the report. 

The results of the study, which focused on 13 coastal counties in South Carolina located within 50 miles of the coastline, are drawn from a model simulating hurricane size, intensity, track and landfall locations under two scenarios: if ocean temperatures remain unchanged from 2005 to 2100, and if they warm at a rate predicted by the IPCC’s worst-case scenario.

Under the 2005 climate scenario, the study estimated that the expected loss in the region due to a severe hurricane — one with a 2% chance of occurring in 50 years — would be $7 billion. Under the warming oceans scenario, the intensity and size of the hurricane at the same risk level is likely to be much greater, the study found, and the expected loss figure climbs to $12 billion.

“Now what we have,” Mr. Rosowsky said, “are huge existing inventories of structures that weren’t designed for the kinds of wind speeds that might be projected by these hurricane hazard models that take climate change into account.”

Joel Scata, Chicago-based attorney with the water program at the Natural Resources Defense Council, said he “would agree overall with the conclusions that climate change will affect the intensity and severity of hurricanes, especially the damage caused by hurricanes.”

Mr. Scata said the combination of climate change and increasing coastal development will result in more hurricane damage in the coming years.

“The increase in sea surface temperature helps fuel higher-magnitude hurricanes,” Mr. Scata said, “but increases in sea surface temperature also result in sea level rise, which means that less destructive storms — smaller hurricanes — can have a bigger punch because storm surge can go further inland on a higher sea level.”

Mr. Scata said a 2016 report by the Congressional Budget Office concluded that that, over time, the costs associated with hurricane damage will increase more rapidly than the economy will grow.

Mr. Scata called for reducing greenhouse gas emissions and trying to adapt to the impact of climate change, such as making building infrastructure safer and smarter and designing it so that it’s capable of withstanding the larger storms that are predicted to occur.