“All research has shown that here in Iceland the average temperature is closely linked to the temperature of the sea. There is no other single factor that has as big an effect on temperature here as the average temperature of the sea because we’re an island in the middle of the Atlantic Ocean. Therefore, it’s very important for us to follow all the discussion on this topic very closely and all the research and do our part to increase monitoring and measurements here.”
These are the words of Meteorologist Einar Sveinbjörnsson, who spoke to Vísir about newly-published research on the Atlantic Meridional Overturning Circulation (AMOC), a series of currents that bring warm water to the North Atlantic and cool water to the equator, thereby impacting the global climate. While older data suggested the AMOC had been weakening since 1930, new research shows the development in fact began 1,000-1,500 years ago. It has been reported on by global media including the Guardian and the Washington Post, the latter of which call the weakening currents an ‘Achilles’ heel’ of the climate.
Global Warming Could Slow Circulation Further
While global warming is not responsible for the weakening circulation – which includes the Gulf Stream, known to moderate Iceland’s climate – it could accelerate the development. “Other forces were at work, but nonetheless, people have demonstrated that with global warming, there is an increased likelihood that it will slow [the Atlantic Ocean’s circulation] down even more,” stated Einar.
The new findings should encourage Icelanders to pay more attention to this aspect of climate change, Einar says. While the Marine and Freshwater Research Institute does conduct some research related to this area, Einar would like to see much more.
Sea North of Iceland is Warming
Weakening currents in the Atlantic are not the only change impacting climate in Iceland. The sea off Iceland’s north coast is currently warming, likely as a result of less sea ice in the region. The lack of ice means that cold currents arriving from the north are warmer than before.
“This causes winters to be milder in the North and with less severe frost, and often just wet weather, rain, and sleet, which are brought by northerly winds in the middle of winter, as has been the case this winter.”
Einar points out the paradox in that sea temperatures north of Iceland are warming while sea temperatures south of the island may be cooling. “What effect does this have on the climate, what effect does it have on marine life, and just generally Icelanders’ living conditions in the long run?”
Tipping Point Unknown
Einar points out that we don’t yet know what the overall effect of a weakening AMOC could be, but it’s possible it could lead to cooler temperatures in Iceland even as average temperatures rise overall across the globe. “We might need to be more thoughtful and vigilant about these things because we hear so much about the climate warming and global warming, but in the long run this could have the effect that it cools down here [in Iceland]; naturally, since the reason why it’s warmer here than at comparable latitudes in the northern hemisphere is that we are surrounded by warm sea.”
According to Einar, it is also difficult to know where the “tipping point” is: at what point the weakening ocean circulation will cause significant impacts on climate. “[T]his heat and salinity conveyor belt, it’s like some cycles in the atmosphere: they continue on and falter despite changes, but then they come to some kind of cliff edge where things find some new balance and we don’t really know where that is in this context.”
Stefan Rahmstorf, the study’s initiator, suggested it could be less than a century before that tipping point is reached. He stated: “If we continue to drive global warming, the Gulf Stream System will weaken further – by 34 to 45 per cent by 2100 according to the latest generation of climate models. This could bring us dangerously close to the tipping point at which the flow becomes unstable.”
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