One of the primary concerns of abrupt climate change is the hypothesized shutdown of the thermohaline circulation. The sinking of cooler, denser water in the polar circles and the rising of warmer, lighter water in other locations drives this circulation. The concern is that a large influx of fresh water (e.g. from the melting of the Greenland ice sheets) could seriously impair this circulation – which helps keep Europe much warmer climatologically than it would be otherwise.
Recent research posits that the abrupt shutdown of the thermohaline circulation would only be possible if water from the Pacific were prevented from flowing into the Arctic Circle – if the Bering Strait were to close. This happened during the last glacial period (80 to 11kya) when sea levels were much lower than they are today; the land under the Bering Strait was exposed.
Instead, this research concludes that such an abrupt shutdown is unlikely, even given the likelihood of Greenland’s ice sheet melting by significant amounts in the coming century. The thermohaline circulation is likely to slow down in response to the large influx of fresh water (which is flowing into the Atlantic from Greenland at an increasing rate), but isn’t expected to shut down. This is fortunate for Europe, which will have better opportunity to respond to shifting climate change effects, given these results. Other feedbacks in the climate system could still spawn abrupt shifts, but this feedback could be less threatening than previously thought.
Note that these results are only one product of more capable technology: a fully coupled climate model. This requires funding and proper governance, two things that our overly politicized culture challenges.
Cross-posted at SquareState.