The Gulf Stream doesn't shut down, it's a physical phenomenon driven by geostrophic gyres and is an example of an intensified western boundary current (pdf): h

The Gulf Stream doesn't shut down, it's a physical phenomenon driven by geostrophic gyres and is an example of an intensified western boundary current (pdf): https://www.ess.uci.edu/~yu/class/ess228/lecture.10.ocean-circulation.2017.all.pdf https://www.ess.uci.edu/~yu/class/ess228/lecture.10.ocean-ci... If you don't have bottom water formation in the North Atlantic due to increased glacial melt off Greenland, then the Gulf Stream influence on Northern Europe gets blocked somewhat. The claim in the paper is that this will result in North Atlantic sea ice having a larger winter extent thus leading to climatic extremes in the winter in the region. However, this goes against the trend of decreasing summer ice coverage in the Arctic, so you have some countervailing forces involved, and predicting the outcome of this struggle is a difficult thing to model, so this would be a 'maybe' outcome. Note also that the Gulf Stream is currently warming so the struggle between opposing forces has another component: https://www.whoi.edu/press-room/news-release/gulf-stream-is-warming-and-shifting/ https://www.whoi.edu/press-room/news-release/gulf-stream-is-... Best bet seems to be increasing climatic instability on a seasonal basis, a kind of whip-saw situation, and thus the best policy options (given that fossil fuel combustion is apparently going to remain constant for the next three decades by all estimates) is to invest in hardening infrastructure, preparing for heat waves and agricultural impacts as well as floods and cold snaps. Another long-term effect of decreased ocean circulation is oceanic hypoxia and anoxia, which of course is also enhanced by fertilizer runoff.