Robust Weakening of the Gulf Stream During the Past Four Decades Observed in the Florida Straits
Study key findings & significance
- The Gulf Stream transport of water through the Florida Straits has slowed by 4% over the past four decades, with 99% certainty that this weakening is more than expected from random chance.
- The paper does not conclude whether the Gulf Stream weakening is due to climate change or to natural factors, stating that future studies should try to identify the cause of the weakening.
Author quotes
"This is the strongest, most definitive evidence we have of the weakening of this climatically-relevant ocean current."
Chris Piecuch, co-author and physical oceanographer with the Woods Hole Oceanographic Institution
"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. 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."
Lisa Beal, co-author and professor of Ocean Sciences at the Rosenstiel School of Marine, Atmospheric, and Earth Science at the University of Miami, Florida
Abstract
The Gulf Stream is a vital limb of the North Atlantic circulation that influences regional climate, sea level, and hurricane activity. Given the Gulf Stream's relevance to weather and climate, many studies have attempted to estimate trends in its volumetric transport from various data sets, but results have been inconclusive, and no consensus has emerged whether it is weakening with climate change. Here we use Bayesian analysis to jointly assimilate multiple observational data sets from the Florida Straits to quantify uncertainty and change in Gulf Stream volume transport since 1982. We find with virtual certainty (probability P > 99%) that Gulf Stream volume transport through the Florida Straits declined by 1.2 ± 1.0 Sv in the past 40 years (95% credible interval). This significant trend has emerged from the data set only over the past ten years, the first unequivocal evidence for a recent multidecadal decline in this climate-relevant component of ocean circulation.
