"Study: Earth's Roughly Warmest in About 100,000 Years"

"A new study paints a picture of an Earth that is warmer than it has been in about 120,000 years, and is locked into eventually hitting its hottest mark in more than 2 million years.

As part of her doctoral dissertation at Stanford University, Carolyn Snyder, now a climate policy official at the U.S. Environmental Protection Agency, created a continuous 2 million year temperature record, much longer than a previous 22,000 year record. Snyder's temperature reconstruction, published Monday in the journal Nature , doesn't estimate temperature for a single year, but averages 5,000-year time periods going back a couple million years.

Snyder based her reconstruction on 61 different sea surface temperature proxies from across the globe, such as ratios between magnesium and calcium, species makeup and acidity. But the further the study goes back in time, especially after half a million years, the fewer of those proxies are available, making the estimates less certain, she said."

Seth Borenstein reports for the Associated Press September 26, 2016.