Strongest ocean current speeding up and scientists blame humans
Earth’s ocean currents are known as the ‘‘global conveyor belt’’ – a planet-wide system that moves warm water north and cool water south.
Now, the strongest current of all is speeding up – and humans are to blame.
That’s the conclusion of a study in the journal Nature Climate Change that finds ‘‘robust acceleration’’ in the Antarctic Circumpolar Current (ACC).
The current, which circulates around Antarctica, is the planet’s strongest, and the only one that isn’t blocked by any land masses. The huge, circular current takes water clockwise around the globe, pushing more water than any other current and keeping Antarctica, which it encircles, cold.
Scientists used decades’ worth of data for the study, including satellite data on the height of the sea surface and information collected by Argo, an international fleet of robotic instruments that float all over the world’s oceans.
Though the current is mostly driven by wind, the researchers found that the acceleration is largely because of changes in the ocean’s heat. When the difference between temperatures between hot and cold waters increases, the currents that border them speed up.
That’s what’s happening to the ACC, and the researchers say human-caused global warming is to blame. The region absorbs much of the heat that human activity pumps into the atmosphere.
As the planet continues to warm, the researchers expect the trend to continue.
While scientists are still working to understand the consequences of accelerating currents, they believe faster circulation will change the way heat is distributed in the world’s oceans and affect marine life in areas that receive warmer waters.
Earlier this year, researchers found that the current sped up in the past, too – between 115,000 and 130,000 years ago during the last interglacial period. That acceleration may have caused everything from weather changes to a decline in the ocean’s ability to absorb carbon dioxide. Their work was published in the journal