Deep in the Atlantic, a vast circulation of water carries heat from the tropics towards Greenland. This is the Atlantic meridional overturning circulation, or Amoc. It does this work largely out of sight, so doesn’t have the public profile of rainforests, polar ice caps or other huge climate-regulating systems.
Recent studies suggest it is weakening. If it slows further, northern Europe could experience much colder winters even as the world warms, while tropical monsoons could shift, and sea levels could suddenly rise along the US east coast.
