The climate is changing at a pace that's far faster than anything seen in 65 million years, a report out of Stanford University says.
The amount of global temperature increase and the short time over which it's occurred create a change in velocity that outstrips previous periods of warming or cooling, the scientists said in research published in today's Science.
If global temperatures rise 1.5 degrees Celsius over the next century, the rate will be about 10 times faster than what's been seen before, said Christopher Field, one of the scientists on the study. Keeping the temperature increase that small will require aggressive mitigation, he said.
If the Earth stays on its current course without reversing greenhouse gas emissions, and global temperatures rise 5 degrees Celsius, as scientists say is possible, the pace of change will be at least 50 times and possibly 100 times swifter than what's occurred in the past, Field said. The numbers are imprecise because the comparison is to an era 55 million years ago, he said.
"The planet has not experienced changes this rapid in 65 million years," Field said. "Humans have never seen anything like this."
Field, in the school's Department of Global Ecology with the Carnegie Institution for Science, and Noah Diffenbaugh, an associate professor of environmental Earth system science, reviewed and synthesized existing research on climate change for a special issue of Science: "Natural Systems in Changing Climates."