Humanity is entering a phase of grave uncertainty as rising temperatures wreck havoc on our planet. Researchers from Yale University and the University of Southhampton have found evidence that Arctic ice loss may be having a negative impact on the Atlantic Meridional Overturning Circulation (AMOC), the largest ocean circulation system on Earth. A complex system not easily explained by talking heads scoring political points, AMOC helps regulate ocean and atmospheric temperatures – and its collapse would have repercussions that not even scientists can properly predict.
“The ongoing decline of Arctic sea ice exposes the ocean to anomalous surface heat and freshwater fluxes, resulting in positive buoyancy anomalies that can affect ocean circulation,” the researchers wrote in a new study published recently in Nature.
“It is found that on decadal timescales, flux anomalies over the subpolar North Atlantic have the largest impact on the AMOC, while on multi-decadal timescales (longer than 20 years), flux anomalies in the Arctic become more important. These positive buoyancy anomalies spread to the North Atlantic, weakening the AMOC and its poleward heat transport. Therefore, the Arctic sea-ice decline may explain the suggested slow-down of the AMOC and the ‘Warming Hole’ persisting in the subpolar North Atlantic.”
So what does this mean?
Trevor Nace, a geologist, explains for Forbes:
“This process whereby water is transported into the Northern Atlantic Ocean acts to distribute ocean water globally. What’s more important, and the basis for concern of many scientists is this mechanism is one of the most efficient ways Earth transports heat from the tropics to the northern latitudes. The warm water transported from the tropics to the North Atlantic releases heat to the atmosphere, playing a key role in warming of western Europe…”
Since this is largely unprecedented, it is uncertain exactly what will happen if the AMOC collapses, or how it will affect global weather patterns. But we do know that even small shifts in climate can result in dramatic changes – evidenced by the growing number of droughts, floods and other natural disasters worldwide. In November, temperatures in the Arctic were 20C degrees higher than normal, according to an Arctic Resilience Report. The best way to slow down this trend is to release fewer greenhouse gases into the atmosphere, which requires a shift away from burning fossil fuels and other carbon-producing industries. And that requires leadership.
Images via NOAA, NASA