"The research found “an almost complete loss of stability over the last century” of the currents that researchers call the Atlantic meridional overturning circulation (AMOC). The currents are already at their slowest point in at least 1,600 years, but the new analysis shows they may be nearing a shutdown.
Such an event would have catastrophic consequences around the world, severely disrupting the rains that billions of people depend on for food in India, South America and West Africa; increasing storms and lowering temperatures in Europe; and pushing up the sea level off eastern North America. It would also further endanger the Amazon rainforest and Antarctic ice sheets."
this is obviously bad news, but i do wish journalists would stop conflating the gulf stream with the AMOC. the gulf stream is a warm surface current generated by prevailing north-easterly winds coming from north america which in turn are a consequence of that continent’s geography (in particular, the rocky mountains). that will not be changing for as long as those mountains are there. the AMOC is a broader term, which includes the gulf stream but also a cold deep sea component of it which flows in the opposite direction, towards the south. these two components are linked by a region of mixing in the nordic sea, where a huge amount of dep sea water rises up and surface waters sink (this is the “overturning” part of the Atlantic meridonial overturning circulation). it’s this system as a whole, not the warm northwards surface flow, which is destabilising due to climate change. now, this gets a little more complex when you consider that the most north-easterly limb of the gulf stream which travels past the british and irish isles and further north, the north atlantic drift, is driven by thermohaline circulation (the system that is falling apart here) and not the rocky-influenced wind patterns. however, this shutting down is a very different situation to the gulf stream as a whole collapsing, with different effects.
with this in mind, it’s evident that the sensationalist articles you might read about europe “freezing over” in a Day After Tomorrow style event are simply wrong. especially considering we now know that the gulf stream isn’t even responsible for most of the relative warmth of european winters compared to say, siberia or nunavut (other factors contribute more). modern climatology has known this for decades. what is far more likely to happen is a) an increase in heatwaves and dramatic weather events in europe; b) major sea level rise on the east coast of north america, up to four times the global average rising that we expect; c) significant reductions in the oxygenation of the oceans as the mixing between surface waters and deep sea ones slows immensely; d) the end of the largest single carbon sink in the northern hemisphere, as the AMOC also sequesters a huge amount of carbon dioxide and kindly takes it down to the bottom of the ocean where it remains for millenia. those are all very bad consequences, but they’re not what the media talks about when discussing this terrifying trend - they love to stick to the ARCTIC EUROPE nonsense and thus will feed another generation of climate change deniers in europe who will grow up reading those headlines and then conclude that it was all a myth in 20 years when we’re instead seeing warmer summers as a result of the rapidly increasing greenhouse effect.
Thank you for writing such a detailed explanation!
Would you mind elaborating on b? Why would the sea level rise on the east coast of America be so much higher?
It’s quite a complex and not well understood phenomenon. Here’s a research paper from 2019 with some robust reasoning. As far as I understand, it’s a consequence of the fact that the AMOC transports a huge quantity of heat north from the tropics along the Atlantic coast of the US, and as this heat transfer slows down, that will lead to changes in the temperature of the ocean along the eastern seaboard, which hence causes thermal expansion of the water, and that is part of what drives this effect. But as I said, it’s not super well understood - this is an effect that our observations see is happening already, and which our numerical computer models of the Atlantic ocean also show occuring with a slowdown in AMOC.
Thank you for the explanation.
Doomer clickbait works just as well as any other kind for for-profit media vampires.
Can you point me towards a good source to learn more on this? Preferably something with scientific credentials which isn’t completely unreadable for someone with only a background in social sciences.
