16,000 Years Ago, Greenland Melting Pushed Antarctic Temps Up 5C, Raise CO2 Content By 40 ppm

[hatrack]

Sixteen thousand years ago, Greenland melt set off a cascade of impacts to the world ocean and atmosphere that led to the dredging of carbon rich waters from deep below the Pacific surface. These waters then disgorged enough carbon into the atmosphere to ultimately raise CO2 levels by 40 parts per million.

(Related: Bad Climate Wind Rises.)

A recent report in Nature Communications found that:

“During this earlier period, known as Heinrich stadial 1, atmospheric CO2 increased by a total of ~40ppm, Antarctic surface atmospheric temperatures increased by around 5°C and Southern Ocean temperatures increased by 3°C.”

How did it all happen? According to the science, Greenland melt slowed down North Atlantic Deep Water formation. This, in turn, caused the North Atlantic to cool and the South Atlantic to warm. The resulting change in temperature then shoved the band of stormy weather called the Inter-Tropical-Convergence-Zone southward. Subsequently, the westerlies in the Southern Hemisphere were shifted poleward and strengthened. Stronger, more southward running winds around the southern pole dredged up carbon rich deep water near the pole and on into the Pacific. This carbon then transferred to the atmosphere.

It’s an interesting bit of science. But it has a good degree of relevance to the present day. That’s because Greenland is again melting greater volumes of water into the North Atlantic. The North Atlantic is again cooling. And the Southern Ocean winds are again being driven south as they strengthen.

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(How Greenland melt pulled carbon from the Southern Ocean. A process that is being driven to repeat by present human-forced climate change. Image source: Nature Communications.)

EDIT

https://robertscribbler.com/2018/07/11/how-greenland-melt-can-kick-off-a-warm-ill-wind-near-antarctica/

[NickB79]

1. So instead of 500ppm by mid-century, we could be looking at 550+

If it pops off anytime soon.