The Northeastern coast of the U.S. could be struck by more frequent and powerful hurricanes in the future due to shifting weather patterns, according to new research presented in a study led by Durham University in the U.K.
This is because hurricanes have gradually moved northwards from the western Caribbean toward northern North America over the past few hundred years, the study found. New York and other major cities along the Northeast coast of the U.S. could come under increased threat from these severe storms and need to be better prepared for their potential impact, according to the research.
“Our research shows that the hurricane risk to the Northeastern coast of the United States is increasing as hurricanes track further north,” said Dr Lisa Baldini, the study’s lead author in the department of geography at Durham University. “Since the 19th Century, this shift was largely driven by man-made emissions, and if these emissions continue as expected, this will result in more frequent and powerful storms affecting the financial and population centers of the Northeastern United States.”
The findings are published in the journal Scientific Reports. Researchers reconstructed hurricane rainfall for the western Caribbean dating back 450 years by analyzing the chemical composition of a stalagmite collected from a cave in southern Belize, Central America.
The research found that the average number of hurricanes at the Belize site decreased over time. When the hurricane history of Belize was compared with documentary hurricane records from places such as Bermuda and Florida, this information showed that Atlantic (Cape Verde) hurricanes were moving to the north rather than decreasing in total numbers.
The researchers suggest that this change in hurricane track was caused by the expansion of atmospheric circulation belts driven by increasing carbon dioxide emissions.
Although natural warming over the centuries has had some impact on shifting hurricane tracks, the researchers found a marked decrease in hurricane activity in the western Caribbean. This coincided with the late 19th Century industrial boom associated with increasing carbon dioxide and sulphate aerosol emissions to the atmosphere.
The researchers said that initial regional cooling of the Northern Hemisphere due to increased industrial aerosol emissions should have pushed the hurricane tracks southward since industrialization. However, rising amounts of atmospheric carbon dioxide had overridden this effect by expanding the Hadley cell – a pattern of circulating air in the Earth’s tropical belt – pushing hurricane tracks further north, away from the western Caribbean towards the Northeastern U.S.
This suggests that from the late 19th Century, manmade emissions have become the main driver behind shifting hurricane tracks by altering the position of global weather systems, the researchers said.
If future trends in carbon dioxide and industrial aerosol emissions continue as expected, hurricanes could shift even further northward, exacerbating the risk to the Northeast coast of the U.S., they added.
“Aerosols from volcanoes and industrialization in the Northern Hemisphere have a cooling effect, which tend to shift moisture belts and hurricane tracks southward, closer to the equator,” said Dr. Amy Frappier, co-author of the report in the geosciences department at Skidmore College in the U.S. “On the other hand, warming from more carbon dioxide in the air tends to expand the Earth’s tropical belt, pushing hurricane tracks further north away from the western Caribbean and towards the Northeastern U.S. This suggests that the tracks of Atlantic hurricanes have responded more to warming than to regional cooling.”
In 2012, Hurricane Sandy struck the Caribbean and much of the eastern seaboard of the U.S., stretching as far north as Canada. At least 233 people died as a result of the storm. A large number of U.S. states were affected by Hurricane Sandy, with New York and New Jersey suffering the greatest impacts.
“Given the devastation caused by Hurricane Sandy, it is important that plans are put in place to protect against the effects of similarly destructive storms which could potentially occur more often in the future,” Baldini said.
The researchers added that the northward shift in hurricane tracks may not reduce the risk of tropical cyclones in the Caribbean.
“Although hurricane tracks have gradually moved northwards away from the western Caribbean, rising sea surface temperatures could promote the development of cyclonic storms within the western Caribbean,” said Dr. James Baldini, co-author of the report in Durham University’s department of earth sciences, said. “Consequently, tropical cyclone activity across the western Caribbean may remain essentially stable over the current century, which has important implications for water availability in this region. However, increased sea surface temperatures also provide extra energy, potentially fueling larger storms. We therefore need to prepare for the effects of more frequent landfalls of larger storms along the Northeast coast of the United States and stronger storms impacting the Caribbean.”
The research was funded by the European Research Council; the National Science Foundation; the Alphawood Foundation; the Schweizer National Fund, Sinergia; and the Inter-American Institute for Global Change Research.
Source: Durham University