By Beth Geiger
About 3.5 billion years ago, Earth’s oceans were cool, not inhospitably hot as previously thought. In fact, the entire planet at the time was probably locked in a cold snap that lasted at least 30 million years, a new study concludes. The findings, published online February 26 in Science Advances, could change the view of Earth’s ancient climate and life’s earliest years.
“This is the first evidence that over the entire [last] 3.5 billion years, Earth has operated within a temperature range that suits life,” says Maarten de Wit, a geologist at Nelson Mandela Metropolitan University in Port Elizabeth, South Africa.