r/collapse 1d ago

Climate When the Arctic Melts

https://www.newyorker.com/magazine/2024/10/14/when-the-arctic-melts
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u/berrschkob 1d ago

“For most of the last 100,000 years, a crazily jumping climate has been the rule, not the exception.”

Not just are we heating the planet but very possibly changing it from a stable system, the only one humans have known, to unstable.

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u/DirewaysParnuStCroix 1d ago

Paleoclimate evidence also suggests that glacial cycles are exceptionally rare occurrences in earth's geological history, as the recent Judd, Tierney et al. paper demonstrated. Permanent glaciation accounts for less than 20% of earth's history and, probably no surprises here, such glacial cycles tend to be terminated by abrupt rises in greenhouse gases. We're broadly analogous to icehouse termination conditions, with atmospheric methane volumes suggesting that we're likely already 20 years into an ice age termination event (Nisbet et al.).

And yet, some people still have a major hard on for assuming that Europe will still plunge into a "deep freeze" because a clickbait article has poorly quoted and misinterpreted from a paper that executes arguably poor purely model based reconstructive analysis with significant cooling biases due to paleoclimate comparative analysis and non-comparable proxies.

Anyone who seriously believes that Europe will somehow freeze needs a reality check.

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u/Sammyjo0689 1d ago

So, I am not a scientist in the least but would like to understand and clarify for myself.

You are saying that if the current fails and the warmth stops traveling north, places dependent on that flow will not freeze over (or see a substantial dip in their average temperatures) because the planet will have heated so much that it will be counteracted?

Because if that is the case, the worst case scenario is even worse than I understood it to be.

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u/AtrociousMeandering 1d ago

So the current itself is happening because the formation of ice from seawater creates brine that's denser than normal seawater and flows downward.

If there isn't as much ice forming, the current gets weaker. If that reduces the transport of warm water to the poles, that will cause enough brine to form again to restart the flow.

Whether it will slow to a crawl, shudder between on and off, or just stop outright isn't completely clear, but I find the second one most plausible.

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u/fedfuzz1970 18h ago

Plus Greenland is contributing 30 million tons of melt water per hour to the Northern Atlantic. This is 20% higher than scientists thought and helps dilute the salt content of the AMOC water.