Following the KT extinction post, an interesting news story this week suggested that the Quaternary Younger Dryas (YD) event, may also have been a result of an impact.
The Younger Dryas event was a period of rapid cooling between 12,900 and 11,700 years BP and it temporarily reversed the effects of warming from previous millennia. It is characterised by a temperature decrease of 2-6°C. Whilst modern climate change is abrupt warming, the YD was abrupt cooling and for many years its cause was elusive. The rapidity of the YD led to suggestions of sudden volcanism or an extra-terrestrial impact for its cause. This week, it was revealed that a crater lying beneath Greenland, known as the Hiawatha crater, can be dated to around 13,000 years BP, just before the onset of the YD.
The huge release of GHG’s and heat from the impact may have led to a massive influx of glacial meltwater into the oceans, reorganising oceanic circulation, in particular, shutting down the North Atlantic "Conveyor", which is responsible for circulating warm tropical waters northwards. This conveyor has reportedly slowed by 15% over the last few decades as a result of warming. Whilst this could result in cooling, any disruption to oceanic circulation can prove disastrous to global climate and marine life.
Whilst impacts appear destructive and are associated with mass release of energy and heat, could they be a potential saviour in reversing global warming? Although they might not be a saviour for life itself...
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