New analysis by climatologists has raised concerns that regions around the North Atlantic, which has long had a climate 5 degrees Celsius warmer than parts of the world on a similar latitude, has a significant chance of rapidly cooling by 2100. The cooling could happen quickly and suddenly, occurring over the course of just ten years. Such a prospect is more drastic than even the most dire predictions up until now regarding climate change in the Atlantic.

A team of British and French researchers from Oceanic and Continental Environments and Palaeoenvironments laboratory at the University of Bordeaux, and the University of Southampton used an algorithm to examine 40 climate models considered by the International Panel on Climate Change’s (IPCC) Fifth Assessment Report.

Their findings, which were published in the Nature Communications Journal, predict a 50 percent chance of rapid cooling in the North Atlantic, far higher than any predictions by the IPCC.  Currently accepted models predict a slowing of the meridional overturning circulation (MOC), a broader phenomenon which underlies the Gulf Stream, which is responsible for bringing warm temperatures to the land surrounding the North Atlantic. A slowing of this phenomenon would mean a massive disruption of the climate system in the area.

The IPCC estimated in 2013 that such a slowdown would occur gradually, suggesting a rapid cooling in the North Atlantic was unlikely.

However, when EU oceanographers re-examined the 40 projections with a focus on the Labrador Sea in the Atlantic’s northwest corner, where a convection system feeds the wider Atlantic’s MOC. In winter, surface temperatures drop, which increases the density in those areas, causing those waters to sink. These displace deeper waters, which then carry their higher temperatures to the surface. This prevents ice caps from forming in those areas.

Using an algorithm that detected brief variations in ocean surface temperatures, the British and French researchers found that seven  models out of the 40 predicted a total halt to convection, which could cool the Labrador Sea by 2 to 3 degrees Celsius over just 10 years – which would lead to a drastic reduction of North Atlantic coastal temperatures.

The researchers said they will one day be able to test the projections against real data, from projects such as OSnap, which will use instruments to collect data from sub polar areas such as the North Atlantic.

If these predictions to come to fruition, it will mean significant changes for the North Atlantic – especially in northwestern Europe.

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