The Atlantic Meridional Overturning Circulation (AMOC), a vast system of ocean currents, is under pressure due to global warming. This system, which carries warm surface water towards the Arctic and returns colder water thousands of miles south, is crucial in shaping the climate and weather patterns in the UK and north-west Europe. The AMOC's weakening could lead to more extreme weather swings, including colder winters, even as average global temperatures continue to rise. This is because the AMOC helps moderate the climate by moving heat from the tropics to the poles. The AMOC's weakening is evident in the North Atlantic's 'cold blob', a region that has stubbornly refused to warm up despite the global pattern. This could be a clear fingerprint of AMOC weakening. However, the evidence is complex, and the future of the system cannot yet be reduced to a simple story of imminent collapse. The AMOC's weakening could lead to more extreme weather patterns, including continued risk of extreme summer heat, greater exposure to cold winters, and more volatile weather generally. The science does not offer a neat ending, but it does offer probabilities, warnings, and caveats. The safest response is already clear: cutting emissions reduces the pressure on the AMOC and mitigates the risk of its weakening. The AMOC's future remains uncertain, but the need for action is clear.
