When Hurricane Sandy made landfall near New York City nearly a decade ago, bringing massive storm surges and 7 inches of rain that caused widespread flooding and blackouts, superstorms were viewed as an extremely rare event. Although common in areas close to the equator, including the Caribbean and the Gulf Coast, such storms rarely strike the northeastern US directly.
But a new study suggests that as the planet warms, storms will become more common in mid-latitude regions — between 30 and 60 degrees of latitude in both hemispheres — including New York City and Boston as well as Beijing, Tokyo. and other large cities. in East Asia and Australia.
“In places like New York, which are not in the deep tropics, hurricanes always occur, but only rarely,” Joshua Studdholm, a Yale University climate physicist and lead author of the study, published last month in the journal Nature Geoscience. “Climate science is changing and this is likely to be a shock.”
An extended storm range means more people as well as homes and businesses in coastal areas may be at risk, said Jim Kosin, a former National Oceanic and Atmospheric Administration scientist who was not involved in the new research.
The equatorial region that gives rise to tropical cyclones—known as hurricanes in the Atlantic and typhoons in the western Pacific—is likely to expand toward both poles as meteorological conditions favorable for tropical-cyclone formation become more common. .
“Even a small polar shift in the mean latitude where tropical cyclones track can cause very large changes in risk at higher latitudes,” Dr. Kosin, who now works for The Climate Service, a climate-risk analysis company.
Hurricanes typically develop in areas where prevailing winds are mild and sea surface temperatures are above 80 degrees Fahrenheit. Such conditions are common in tropical regions but so far from the equator and closer to the poles. However, as global temperatures rise, jet streams — western bands of high winds that circle up to 9 miles above Earth — are weakening and shifting in mid-latitude regions. This allows hurricanes and typhoons to form over a wider range.
According to a report released in August by the Intergovernmental Panel on Climate Change, average global temperatures have increased by two degrees Fahrenheit over the past 170 years. The report says temperatures will continue to rise by at least 0.7 degrees until 2100, a phenomenon attributed to greenhouse gas emissions “disproportionately due to human activities,” including the burning of fossil fuels.
According to the study, the last time storms formed at high latitudes was during the Pliocene epoch between 5.3 million and 2.6 million years ago marked by higher temperatures and higher levels of atmospheric carbon dioxide.
“The tropical cyclones of the 21st century will likely occupy a wider range of latitudes than at any other time during the past three million years,” said Dr. Studholm said.
His group researched satellite observations of current weather, as well as simulations of Earth’s past and forecasts of future weather. Such simulations have some limitations, as they rely on incomplete data describing the behavior of climate in the past to project future patterns.
“It is very difficult to verify climate models because of the uncertainty in observations, especially for long-term multi-decade changes in global tropical cyclones,” said Hiroyuki Murakami, a project scientist at NOAA’s Geophysical Fluid Dynamics Laboratory. Study. But, he said, based on the study “it was reasonable to anticipate possible polar shifts in future tropical cyclone latitudes”.
In light of the potential threat, some cities are not waiting for accurate information.
Last year, New York City’s emergency management updated the city’s coastal-hurricane plan, using new data to more accurately define hurricane-related flood risk areas and accordingly set the boundaries of the city’s six storm evacuation zones. Changed.
“It continues to educate and prepare New Yorkers for the potential impacts of hurricanes, as climate change increases in their frequency and intensity,” the agency said in a statement.
According to Rev. Mariama, Boston is expanding efforts to prepare for a potentially wet and stormy future, in part by modifying waterfront parks with berms and flood walls to better manage rising water and A new waterfront park designed to withstand hurricanes and devastating floods is under construction. White-Hammond, the city’s head of environment, energy and open space.
“With hurricanes, we don’t know how and when, but we already know where our lowlands are,” she said. “We know enough to take action.”
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