An influential current system in the Atlantic Ocean, which plays a vital role in redistributing heat throughout our planet’s climate system, is now moving more slowly than it has in at least 1,600 years. That’s the conclusion of a new study published in the journal Nature Geoscience from some of the world’s leading experts in this field.
Scientists believe that part of this slowing is directly related to our warming climate, as alters the balance in northern waters. Its impact may be seen in storms, heat waves and sea-level rise. And it bolsters concerns that if humans are not able to limit warming, the system could eventually reach a tipping point, throwing global climate patterns into disarray.
The Gulf Stream along the U.S. East Coast is an integral part of this system, which is known as the Atlantic Meridional Overturning Circulation, or AMOC. It was made famous in the 2004 film “The Day After Tomorrow,” in which the ocean current abruptly stops, causing immense killer storms to spin up around the globe, like a super-charged tornado in Los Angeles and a wall of water smashing into New York City.
As is the case with many sci-fi movies, the plot is based on a real concept but the impacts are taken to a dramatic extreme. Fortunately, an abrupt halting of the current is not expected anytime soon — if ever. Even if the current were to eventually stop — and that is heavily debated — the result would not be instant larger-than-life storms, but over years and decades the impacts would certainly be devastating for our planet.
Recent research has shown that the circulation has slowed down by at least 15% since 1950. Scientists in the new study say the weakening of the current is “unprecedented in the past millennium.”
Because everything is connected, the slowdown is undoubtedly already having an impact on Earth systems, and by the end of the century it is estimated the circulation may slow by 34% to 45% if we continue to heat the planet. Scientists fear that kind of slowdown would put us dangerously close to tipping points.
Importance of the Global Ocean Conveyor Belt
Because the equator receives a lot more direct sunlight than the colder poles, heat builds up in the tropics. In an effort to reach balance, the Earth sends this heat northward from the tropics and sends cold south from the poles. This is what causes the wind to blow and storms to form.
The majority of that heat is redistributed by the atmosphere. But the rest is more slowly moved by the oceans in what is called the Global Ocean Conveyor Belt — a worldwide system of currents connecting the world’s oceans, moving in all different directions horizontally and vertically.
Through years of scientific research it has become clear that the Atlantic portion of the conveyor belt — the AMOC — is the engine that drives its operation. It moves water at 100 times the flow of the Amazon river. Here’s how it works.
A narrow band of warm, salty water in the tropics near Florida, called the Gulf Stream, is carried northward near the surface into the…