Researchers model ancient temperatures during the early age of mammals

Avatar By Lliane Hunter | 2 years ago

A team of geochemists has reconstructed what temperatures would have been like during the early age of mammals around 50 million years ago, discovering that was unbelievably hot, writes Peter Brannen for The Atlantic.  During this age, the atmosphere held around 1,000 parts per million (ppm) of carbon dioxide, which is what scientists predict humanity will reach by the end of the century. “But exactly how much it will warm by the end of the century, we don’t know,” says David Naafs, an organic geochemist at the University of Bristol, and lead researcher. “Based on our research of these ancient climates, though, it’s probably more than we thought.”

Naafs and colleagues released a study in Nature Geoscience that modeled temperatures during the high-COatmosphere of the late Paleocene and early Eocene epochs that began the age of mammals. They studied examples of lower-quality coals called lignites, or fossilized peat collected from around the world, Brannen explains. They then “reverse engineered” the ancient climate by analyzing temperature-sensitive structures of lipids produced by fossil bacteria and archaea.  They found that temperatures during this time in ancient U.K., Germany, and New Zealand had mean annual temperatures of 73-84 degrees Fahrenheit, 18-27 degrees Fahrenheit warmer than modern times. “So Europe would look like the Everglades and a heat wave like we’re currently experiencing in Europe would be completely normal. That is, it would be the everyday climate,” Naafs reports. Though in modern times, this temperature is registering as a heat wave, over 50 million years ago this would have been the baseline.

Brannen notes that it’s important not to confuse our modern world with ancient ones. The early age of mammals was different—continents were in slightly different positions, and ocean circulation differed. Alarmingly, scientists predict that if we do push CO2 to around 1,000 ppm by the end of the century, the warming will persist, and the earth will continue to change for, what will seem like, an eternity.