Chicxulub for the win!
Posted: Wed 20 Jun 2018, 12:43:32
According to a recent article at space.com, the 65-million-year-old impact of the Chicxulub meteor/comet/asteroid/whatever caused Climate Change impacts that subjected Earth to approximately 100,000 years of elevated temperatures, averaging 5 degrees C above global averages. The "triple whammy" went something like this:
1) At the time of impact, the mechanical impact of the collision released enormous amounts of energy, and ignited fires that swept all continents surrounding the Atlantic, save possibly the remote tundra of Eastern Asia and the continent of Australia, which caused even more warming due to combustion of more than half of the plant biomass at the time. This temperature increase lasted for hours to days.
2) The huge amounts of dust and smoke released into the atmosphere circled the globe, blocking sunlight and causing global temperatures to plummet for a period lasting months to decades, in a grim preview of what might result if we ever experience "Nuclear Winter".
3) The huge amounts of carbon dioxide released then caused a period of Global Warming, and the new information is that recovery from this planetary scale warming period took over 100,000 years.
The implication being: If human activity is increasing global temperatures, the outside bound for the healing period when FF combustion ends may be on the order of 100,000 years.
The climate information came from the rather complete record of fish remains (teeth, scales, and bones) found in the African lakes of the El Kef section of Tunisia. This has long been known to contain one of the most complete and best preserved fossil records of the Chicxulub extinction event and the continuous periods before and after the impact. In this case, temperatures were derived from the (relatively sensitive to temperature) ratios of oxygen 16 to oxygen 18.
https://www.space.com/40690-dino-killing-asteroid-impact-warmed-earth.html