Would the reoccurrance of a period like the younger dryas stop global warming?

https://en.m.wikipedia.org/wiki/Younger_Dryas

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That’s sort of a chicken-and-egg question. The warming trend that was occuring at the time was halted by the Younger Dryas (as the one prior was halted by the Older Dryas), so you’re sort of asking, “If the climate cooled would that halt global warming?” It’s a circular question.

The exact causes of the Younger Dryas aren’t well understood, but the majority believe it was associated with a flood of fresh water into the North Atlantic that temporarily shut down the thermohaline cycle and stopped the heat transfer from the equatorial regions to the polar regions (at least in the Atlantic). There is some argument over exactly what triggered this to happen (ice dam breaking on its own as a result of warming temperatures, a meteor impact, volcanic eruptions, etc).

At present we don’t have any near the amount of fresh water (in the form of ice and meltwater) available as there was just prior to the Younger Dryas, so that exact scenario is less likely now than in the past. However, it is still a cause for concern with melting of Greenland’s ice, and there does seem to be some evidence that the thermohaline cycle is slowing down.

While such an event might temporarily put a halt on temperature increases it would not address or halt the reasons why the temperature of the planet is increasing (increasing amounts of greenhouse gasses emitted by humans) and thus wouldn’t fix anything.

Indeed, it would likely make things much worse.

A radical swing in temperatures like that, in the opposite direction of where we are heading now, would massively compound stresses on species across the board leading to spike in extinctions and population drops in other species. Much of Europe would very quickly become a hostile environment to live leading to a mass exodus and a large portion of the 741 million people becoming climate refugees. This rapid drop in temperatures would also destroy agriculture in large parts of the northern hemisphere, leading to massive food stresses at the same time as the mass movement of people.

At the same time this sort of thing would likely lead to massively increased energy use, leading to an over-all increase in greenhouse gasses, making for an extremely chaotic and volatile climate over all.

In the tropics heat would remain in place rather than being transferred away, so while northern areas were suffering from the aforementioned issues, the tropical areas would have their current problems with increasing temperatures and increasingly dangerous weather increased.

In short, it would be a massive disaster, one that would likely unfold even more rapidly than the unfolding one we find ourselves in right now.

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