A new study published in the Geophysical Research Letters has found that the vital role ocean circulation plays in our climate, weather, and marine life has shifted due to our warming planet. The study reveals for the “first time, independent satellite observational evidence demonstrating that the large‐scale ocean gyres are moving poleward during the past four decades”. The culprit in this shift is the carbon from fossil fuel emissions that we burn for energy.
From the presser:
Eight massive wind-driven ocean currents, called ocean gyres, move water around our planet. There are three in the Atlantic Ocean, three in the Pacific Ocean, and one each in the Indian and Antarctic oceans. These rotating current systems largely determine the weather and marine productivity in our planet’s coastal regions.
In the new study, experts at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), analyzed long-term global satellite data of ocean surface temperature and sea levels. Both datasets offer insights into the evolution of large-scale surface currents, and indicate that, in the Northern and Southern Hemisphere alike, the borders of the ocean gyres and their boundary currents are moving closer to the poles, at a rate of more than 800 meters (2,600 feet) per year.
This displacement of tremendous water masses is chiefly driven by global warming, as calculations using a new climate model confirm.
These shifts in the major current systems will have far-reaching consequences for human beings and the environment alike, according to the study’s authors.
“As the western boundary currents continue to shift, the courses of winter storms and of the jet stream are following suit,” Yang said. “At the edges of the eastern boundary currents, we’re now seeing the rich ecosystems begin to shrink, because the shifting currents are changing the living conditions too quickly for marine organisms to adapt.”
Dramatic temperature changes have been observed in the Gulf of Maine, due to the shifting Gulf Stream, resulting in a migration of cod stocks. Researchers have observed similar changes off the Atlantic coasts of Uruguay and Argentina, where the Brazil Current is gradually moving south.
In addition, when boundary currents penetrate higher latitudes, the local sea level rises disproportionately – a problem that communities on the northeast coast of North America are now confronted with. To make matters worse, the displacement of the major subtropical gyres is causing the nutrient-poor regions to expand, reducing the productivity of the ocean as a whole. Accordingly, the shift in the gyres could represent the beginning of a fundamental change in the ocean, according to the study’s authors.