> Then, in 2021, a team of archaeologists dropped a bombshell into this debate: they’d found footprints – unquestionable evidence of a human presence – at White

> Then, in 2021, a team of archaeologists dropped a bombshell into this debate: they’d found footprints – unquestionable evidence of a human presence – at White Sands National Park in New Mexico, dating to between 23,000-21,000 years ago. The article places that date long before the Last Glacial Maximum (LGM): > It [the Clovis point] appeared widely across the continent beginning about 13,400 years ago, near the end of the LGM. Which raises the question of what people were doing in the Americas before the LGM? USGS has this to say about what might have been going on with the climate at the time the White Sands footprints were laid down: > During the late Pleistocene (~129,000 to ~11,700 years ago), full glacial conditions were interrupted repeatedly by abrupt warming events called Dansgaard-Oeschger, or D-O events. In the southwestern U.S., D-O events caused centuries-long megadroughts, which devastated spring ecosystems, lowered lake levels, affected sea-surface temperatures and circulation patterns, and even triggered seismic activity. One of these events, called D-O 2, dates to ~23,500 years ago and was especially impactful to spring ecosystems, as water tables never returned to the same levels after the event that they had maintained for thousands of years prior. https://www.usgs.gov/programs/climate-research-and-development-program/news/discovery-ancient-human-footprints-white https://www.usgs.gov/programs/climate-research-and-developme... Wikipedia notes that D-O events flared up extremely rapidly on a geological timescale: > In the Northern Hemisphere, they [D-O events] take the form of rapid warming episodes, typically in a matter of decades, each followed by gradual cooling over a longer period. ... https://en.wikipedia.org/wiki/Dansgaard–Oeschger_event https://en.wikipedia.org/wiki/Dansgaard–Oeschger_event