by James Kennett et al., March 13, 2019 in CO2Coalition
When UC Santa Barbara geology professor emeritus James Kennett and colleagues set out years ago to examine signs of a major cosmic impact that occurred toward the end of the Pleistocene epoch, little did they know just how far-reaching the projected climatic effect would be.
“It’s much more extreme than I ever thought when I started this work,” Kennett noted. “The more work that has been done, the more extreme it seems.”
He’s talking about the Younger Dryas Impact Hypothesis, which postulates that a fragmented comet slammed into the Earth close to 12,800 years ago, causing rapid climatic changes, megafaunal extinctions, sudden human population decrease and cultural shifts and widespread wildfires (biomass burning). The hypothesis suggests a possible triggering mechanism for the abrupt changes in climate at that time, in particular a rapid cooling in the Northern Hemisphere, called the Younger Dryas, amid a general global trend of natural warming and ice sheet melting evidenced by changes in the fossil and sediment record.