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This claim has been around for a while, but it's unclear if it really is a concern. First, even if large freshwater injections had significant climate impacts

This claim has been around for a while, but it's unclear if it really is a concern. First, even if large freshwater injections had significant climate impacts at the beginning of this interglacial period c. 12k years ago, it doesn't necessarily mean that Greenland ice melt will have the same effect today as the state of the system is very different. Second, the Gulf Stream is a western boundary current driven by physical forces like gyre circulation that are due to the rotation of the Earth and midlatitude coriolis effects, it won't be shut down under warming. See also recently published reports that don't seem to support the idea: (2021) Subpolar North Atlantic western boundary density anomalies and the Meridional Overturning Circulation https://www.nature.com/articles/s41467-021-23350-2.pdf https://www.nature.com/articles/s41467-021-23350-2.pdf In particular rapid warming of the North Atlantic shelf on the North American side seems to be overwhelming many other trends, due to increased heat transport northwards from the tropical Caribbean, leading to subsurface nutrient depletion and fishery collapses, and probably overriding any Greenland-melt-induced cooling: (2021) Changes in the Gulf Stream preceded rapid warming of the Northwest Atlantic Shelf https://www.nature.com/articles/s43247-021-00143-5 https://www.nature.com/articles/s43247-021-00143-5

jamesblonde 2y ago
You don't back up your claim with any evidence: "Second, the Gulf Stream is a western boundary current driven by physical forces like gyre circulation that are due to the rotation of the Earth and midlatitude coriolis effects, it won't be shut down under warming." The experts are not saying what you are claiming here. You provide links which are not directly related to AMOC collapse. I call cherry picking.
- photochemsyn 2y ago
  It's just basic oceanographic physics, that's how midlatitude gyres work. Since you ask: > "The trade winds create the equatorial currents that flow east to west along the equator; the North Equatorial and South Equatorial currents. If there were no continents, these surface currents would travel all the way around the Earth, parallel to the equator. However, the presence of the continents prevents this unimpeded flow. When these equatorial currents reach the continents, they are diverted and deflected away from the equator by the Coriolis Effect; deflection to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. These currents then become western boundary currents; currents that run along the western side of the ocean basin (i.e. the east coasts of the continents). Since these currents come from the equator, they are warm water currents, bringing warm water to the higher latitudes and distributing heat throughout the ocean." https://rwu.pressbooks.pub/webboceanography/chapter/9-1-surface-gyres/ https://rwu.pressbooks.pub/webboceanography/chapter/9-1-surf... The issue is that increased poleward Gulf Stream heat transport could easily overpower the effect of Greenland ice melt outflows into the North Atlantic. This raises other problems, it could still decrease deep ocean ventilation and push the increasing oceanic hypoxia trend.

jamesblonde 2y ago

You don't back up your claim with any evidence: "Second, the Gulf Stream is a western boundary current driven by physical forces like gyre circulation that are due to the rotation of the Earth and midlatitude coriolis effects, it won't be shut down under warming." The experts are not saying what you are claiming here. You provide links which are not directly related to AMOC collapse. I call cherry picking.

photochemsyn 2y ago
It's just basic oceanographic physics, that's how midlatitude gyres work. Since you ask: > "The trade winds create the equatorial currents that flow east to west along the equator; the North Equatorial and South Equatorial currents. If there were no continents, these surface currents would travel all the way around the Earth, parallel to the equator. However, the presence of the continents prevents this unimpeded flow. When these equatorial currents reach the continents, they are diverted and deflected away from the equator by the Coriolis Effect; deflection to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. These currents then become western boundary currents; currents that run along the western side of the ocean basin (i.e. the east coasts of the continents). Since these currents come from the equator, they are warm water currents, bringing warm water to the higher latitudes and distributing heat throughout the ocean." https://rwu.pressbooks.pub/webboceanography/chapter/9-1-surface-gyres/ https://rwu.pressbooks.pub/webboceanography/chapter/9-1-surf... The issue is that increased poleward Gulf Stream heat transport could easily overpower the effect of Greenland ice melt outflows into the North Atlantic. This raises other problems, it could still decrease deep ocean ventilation and push the increasing oceanic hypoxia trend.