The system of ocean currents known as the Atlantic Meridional Overturning Circulation or AMOC plays a crucial role in the global climate, helping to keep Europe relatively mild and to circulate vital nutrients for marine life.
But scientists are worried that the AMOC system might be starting to weaken because of climate change and that, in the worst case scenario, it might eventually collapse.
This could lead to freezing temperatures in Europe and changing rainfall patterns around the world. The Amazon rainforest could dry out, for example, and the monsoon in South East Asia might also be affected.
But there's a lot of uncertainty about the AMOC in our climate models, as well as a gap in real world data because scientists have only been measuring this vital ocean system for a couple of decades.
In this show, The Climate Question hosts Graihagh Jackson and Esme Stallard talk to Professor Penny Holliday. Penny is the Chief Scientific Officer at the UK's National Oceanography Centre. She has been leading research on the strength and variability of AMOC for decades.
Producers: Graihagh Jackson, Diane Richardson and Grace Braddock Sound Mix: Dafydd Evans and Tom Brignell Editor: Simon Watts
Photo by Joe Klamar / AFP via Getty Images