# What triggered the Younger Dryas cooling? · Younger Dryas impact hypothesis > Four answers have been proposed. Meltwater from the retreating ice sheets weakened the Atlantic overturning circulation. leads, with evidence 2 for… Source: https://mysteriesdept.com/mysteries/younger-dryas-impact/questions/QST0D51X99T2T4C/what-triggered-the-younger-dryas-cooling Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) Updated: 2026-10-26T11:59:09+00:00 --- **0** # What triggered the Younger Dryas cooling? Asked 26 Oct 2026 by [**apollo** ](https://mysteriesdept.com/u/apollo)·4 answers·0·0 following **Most likely: meltwater from the retreating ice sheets weakened the Atlantic overturning circulation** Ahead on the evidence, not yet confirmed. It needs two reviews to be accepted. ## Where it stands Four answers have been proposed. Meltwater from the retreating ice sheets weakened the Atlantic overturning circulation. leads, with evidence 2 for: supported by its tests. Three are still possible. ## Why it matters The impact hypothesis was offered as the trigger⁠[[1]](https://mysteriesdept.com/sources/SRC0D51WPR222ST/evidence-for-an-extraterrestrial-impact-12-900-years-ago); the standard account places the event in a sequence of deglacial cold spells driven by ocean circulation⁠[[2]](https://mysteriesdept.com/sources/SRC0D51WXB01CDK/putting-the-younger-dryas-cold-event-into-context). ## Answers 4 [**Meltwater from the retreating ice sheets weakened the Atlantic overturning circulation.** ](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XMH60RGT/meltwater-from-the-retreating-ice-sheets-weakened-the) Supported by its tests Evidence: 2 for Most likely [**Impact-driven fires and an impact winter tipped the climate.** ](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XN8M37Y6/impact-driven-fires-and-an-impact-winter-tipped-the-climate) Failed a test; not refuted outright Evidence: 1 for, 1 against Disputed [**None of these.** ](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XPFP3YK9/none-of-these) Not tested enough to call either way Evidence: none yet Still possible [**Volcanic forcing, from Laacher See or another eruption, pushed a system near a threshold.** ](https://mysteriesdept.com/mysteries/younger-dryas-impact/answers/ANS0D51XP0229RS/volcanic-forcing-from-laacher-see-or-another-eruption-pushed) Failed a test; not refuted outright Evidence: 1 against Disputed ## History 1. 2000[Alley: the GISP2 record shows onset and end within decades, the pattern of circulation switches.](https://mysteriesdept.com/sources/SRC0D51WXJT0RPG/the-younger-dryas-cold-interval-as-viewed-from-central)For: Meltwater from the retreating ice sheets weakened the Atlantic overturning circulation. 1. 2010[Broecker et al. puts forward: meltwater from the retreating ice sheets weakened the Atlantic overturning circulation.](https://mysteriesdept.com/sources/SRC0D51WXB01CDK/putting-the-younger-dryas-cold-event-into-context) 1. 2010[Broecker et al.: the Younger Dryas resembles other abrupt cold events of the last deglaciation.](https://mysteriesdept.com/sources/SRC0D51WXB01CDK/putting-the-younger-dryas-cold-event-into-context)For: Meltwater from the retreating ice sheets weakened the Atlantic overturning circulation. 1. 2014[Holliday et al.: geomorphic, stratigraphic and fire records show no catastrophic change at the boundary.](https://mysteriesdept.com/sources/SRC0D51WRPJ7976/the-younger-dryas-impact-hypothesis-a-cosmic-catastrophe)Against: Impact-driven fires and an impact winter tipped the climate. 1. 2018[Wolbach et al. puts forward: impact-driven fires and an impact winter tipped the climate.](https://mysteriesdept.com/sources/SRC0D51WSNT4DN9/extraordinary-biomass-burning-episode-and-impact-winter) 1. 2018[Wolbach et al.: ice-core combustion markers are said to show a biomass-burning episode at the onset.](https://mysteriesdept.com/sources/SRC0D51WSNT4DN9/extraordinary-biomass-burning-episode-and-impact-winter)For: Impact-driven fires and an impact winter tipped the climate. 1. 2021[Reinig et al. puts forward: volcanic forcing, from Laacher See or another eruption, pushed a system near a threshold.](https://mysteriesdept.com/sources/SRC0D51WTD82RD0/precise-date-for-the-laacher-see-eruption-synchronizes-the) 1. 2021[Reinig et al.: laacher See erupted about 130 years before the onset, too early to be its direct trigger.](https://mysteriesdept.com/sources/SRC0D51WTD82RD0/precise-date-for-the-laacher-see-eruption-synchronizes-the)Against: Volcanic forcing, from Laacher See or another eruption, pushed a system near a threshold. 1. 26 Oct 2026Asked on this site ## Discussion 0 [Add to the discussion](https://mysteriesdept.com/signin?next=/mysteries/younger-dryas-impact/questions/QST0D51X99T2T4C/what-triggered-the-younger-dryas-cooling%23discussion) Help with this question [ **Propose an answer** Something the evidence could support or rule out ] [ **Propose an answer** Something the evidence could support or rule out ](https://mysteriesdept.com/signin?next=/mysteries/younger-dryas-impact/questions/QST0D51X99T2T4C/what-triggered-the-younger-dryas-cooling%23add-answer) [ **Add evidence** A result for or against an answer ] [ **Add evidence** A result for or against an answer ](https://mysteriesdept.com/signin?next=/mysteries/younger-dryas-impact/questions/QST0D51X99T2T4C/what-triggered-the-younger-dryas-cooling%23add-evidence) [ **Ask a sub-question** A smaller question that would help settle this one ] [ **Ask a sub-question** A smaller question that would help settle this one ](https://mysteriesdept.com/signin?next=/mysteries/younger-dryas-impact/questions/QST0D51X99T2T4C/what-triggered-the-younger-dryas-cooling%23add-question) [ **Add a source** A paper, archive record or image ] [ **Add a source** A paper, archive record or image ](https://mysteriesdept.com/signin?next=/mysteries/younger-dryas-impact/questions/QST0D51X99T2T4C/what-triggered-the-younger-dryas-cooling%23add-source) Where it fits Younger Dryas impact hypothesis **What triggered the Younger Dryas cooling?** Key question · you're here [ Ask a question under this one ]