The Atlantic Gulf Stream, which is responsible for weather patterns in North America and Europe, is slowing down. The discovery was published in two studies this week and points to man-made climate change as the reason for the altered system.
The Atlantic meridional overturning circulation (AMOC) is system of ocean currents in the North Atlantic that acts as a conveyor belt to move water and air, creating weather systems and redistributing heat on our planet. The system brings warm, salty water north in the upper layer of the Atlantic, while colder water flows south in the depths of the Atlantic.
Research recently published in science journal Nature by the University College London (UCL) and Woods Hole Oceanographic Institution (WHOI) has found that the circulation of water in the Atlantic has been declining since the 1800s by 15 to 20 percent. The slowing of the currents could exacerbate the impact of climate change such as rising sea levels on the US East Coast and disrupted weather patterns across North America, Europe and North Africa including the increase of flooding, droughts and winter storms.
The weakening of the system isn’t likely to be arrested any time soon and the causes of the system’s slowing down are predicted to continue in the future due to continued carbon dioxide emissions according to lead author David Thornalley.
Researchers took measurements from a 5.2-million-square-kilometer (2-million-square-mile) patch of cold water in the North Atlantic to measure circulation patterns and seasonal temperatures on the ocean’s surface.
These changes are likely in response to increasing carbon dioxide in the atmosphere paired with warmer global temperatures. To track circulation patterns, the teams used sediment historically carried along by the AMOC. It also reconstructed near-surface ocean temperatures at points along the AMOC’s journey to gauge how affected these were by current strength.
According to the study in Nature, the slowdown opens the doors for a potential complete shutdown of the ocean’s current that would be a tipping point. The authors warn such a collapse is at least a few decades away but would be catastrophic.