"Katrina. Harvey. Maria. Dorian. In recent years, hurricanes have killed thousands of people and caused billions of dollars in damage. But getting a handle on how frequently these destructive storms have pummeled the planet is tough because records stretch back only about a century and a half," writes Katherine Kornei for New York Times Science.
Now, research led by Lizzie Wallace, paleoclimatologist in the Massachusetts Institute of Technology/Woods Hole Oceanographic Institution Joint Program in Oceanography, has assembled a 1,500-year history of hurricanes in the Bahamas. They used sediment cores containing sand, coral pieces, shell fragments and organic matter from blue holes on South Andros Island. The data that can be extracted from these deepsea caverns help scientists uncover ancient storms.
The research team used radiocarbon dating to investigate debris deposited in the core's sediment by hurricanes. “I can immediately look at it and say, ‘There’s a hurricane layer,’” said Lizzie Wallace, in the article.
The cores, the researchers say, show variation in storm strength and frequency over time. While the sediment cores don't capture every hurricane that has passed by that blue hole, they more clearly show the impact of intense storms. This may also be because of climate forcing driving the hurricanes' activity and locations. Additionally, the researchers' work shows that there are periods of hurricane activity and inactivity.
Kornei notes, "if the past is an indicator of the future, this lull will be temporary, the researchers suggest. And, they add, an uptick in hurricane activity will affect more than just the Bahamas: Many of the storms that strike the Caribbean continue on to hit the Gulf of Mexico."
Blue holes, a type of sinkhole in the Bahamas, are revered among divers for their deep, clear waters. (Credit: Romona Robbins/Cultura Creative Ltd., via Alamy)