Comment Re:What happened? (Score 5, Informative) 72
Good question, that probably should be addressed in TFA, but isn't. Have a cookie, assuming you're not blocking them. :)
The Earth was exiting a period of relative geological and climatic stability and entering a cooling phase, which would have helped strengthen the AMOC. This process was then enhanced by a large scale volcanic eruption, thought to be in North America, with the ejecta from that and a series of subsequent eruptions leading to a significant deviation from the trendline, a mini-iceage known as the Late Antique Little Ice Age (LILIA) similar to the Maunder Minimum, a multi-decade period of cooler than statistically expected temperatures (up to 2.7C cooler than average in European summers). This is reflected in tree-ring records which show highly stunted growth for the time, ice cores from polar ice cores, and some of the remaining writings from the period that describe widespread crop failures.
The Earth was exiting a period of relative geological and climatic stability and entering a cooling phase, which would have helped strengthen the AMOC. This process was then enhanced by a large scale volcanic eruption, thought to be in North America, with the ejecta from that and a series of subsequent eruptions leading to a significant deviation from the trendline, a mini-iceage known as the Late Antique Little Ice Age (LILIA) similar to the Maunder Minimum, a multi-decade period of cooler than statistically expected temperatures (up to 2.7C cooler than average in European summers). This is reflected in tree-ring records which show highly stunted growth for the time, ice cores from polar ice cores, and some of the remaining writings from the period that describe widespread crop failures.