Gulf Stream Weakening Confirmed With 99% Certainty in New Study

A new study confirms that the Gulf Stream, a strong current of warm water flowing from the Gulf of Mexico into the Atlantic Ocean, has slowed by 4% in the past 40 years. Further, the study authors came to this conclusion with “virtual certainty” greater than 99%, although the paper doesn’t confirm the cause of the weakening.

The Gulf Stream can influence weather and climate, even impacting sea levels and hurricane activity. In addition to warm water, this major ocean current carries heat and carbon and has far-reaching impacts, even affecting temperature and rain in Europe, the study authors explained.

According to the study authors, who published their findings in the journal Geophysical Research Letters, scientists have spent years trying to determine whether there has been weakening in the Gulf Stream because of global warming.

Researchers analyzed data from observations, undersea cables and satellites gathered at the Florida Straits since 1982. The authors used Bayesian modeling to arrive at their conclusion. While the authors couldn’t confirm the reason for changes in the Gulf Stream, they noted that the slowing trend was only made evident in the past 10 years.

Chris Piecuch, lead author of the study and a physical oceanographer with the Woods Hole Oceanographic Institution, compared Bayesian modeling to gathering independent witnesses in a court case.

“We brought all the witnesses to the stand that we could technically involve to bring all these data sets together,” Piecuch explained in a statement. “Once we synthesized the testimony from all the different witnesses, they painted a very clear picture that, indeed, over the past 40 years the Gulf Stream has weakened by about 4%, which is significant. It’s more than you would expect if the current was stable; so, it’s an important change.”

The study is part of a six-year project that will measure changes in the Gulf Stream; however, the authors noted that more research will be needed to determine what is causing the weakening.

“The Gulf Stream is a vital artery of the ocean’s circulation, and so the ramifications of its weakening are global. I used to think of the ocean as our last remaining frontier, wild, pristine, and indomitable,” Lisa Beal, co-author of the study and professor of Ocean Sciences at the Rosenstiel School of Marine, Atmospheric, and Earth Science at the University of Miami, Florida, said in a statement. “It saddens me to acknowledge, from our study and so many others, and from recent record-breaking headlines, that even the remotest parts of the ocean are now in the grip of our addiction to fossil fuels.”

In July 2023, a separate study found that the Atlantic Meridional Overturning Circulation (AMOC), of which the Gulf Stream is a part, could collapse this century, between 2025 and 2095.