Stalagmite from Wisconsin shows evidence of sudden warming during last ice age
https://www.wpr.org/cave-of-the-mounds-stalagmite-global-warming-discovery-ice-age-wisconsin
Researchers with the University of Wisconsin-Madison say a stalagmite from Cave of the Mounds in southern Wisconsin holds clues about the impact of abrupt, global climate changes during the last ice age.
For the first time ever, researchers say there's strong evidence that sudden, global warming events recorded via core samples from the Greenland Ice Sheet reached well into lower latitudes, specifically Wisconsin and the Midwest, between 48,000 and 68,000 years ago.
A team of UW-Madison scientists led by Cameron Batchelor removed a stalagmite about the length of a pinky finger and used chemical and physical analysis to detect telltale signs of sudden warming in the atmosphere. A paper on their research was published this month in the journal Nature Geoscience.
Batchelor said they used oxygen isotopes trapped in the stalagmite's layers to show that temperatures in what is now Wisconsin rose by an average of around 18 degrees Fahrenheit within 10-year periods during the last ice age.
That is definitely abrupt.