In 200 years, humans reversed a climate trend lasting 50 million years, study says

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(CNN) — What do scientists see when comparing our future climate with the past? In less than 200 years, humans have reversed a multimillion-year cooling trend, new research suggests.

If global warming continues unchecked, Earth in 2030 could resemble its former self from 3 million years ago, according to a study published Monday in the journal Proceedings of the National Academy of Sciences finds.

During that ancient time, known as the mid-Pliocene epoch, temperatures were higher by about 2 to 4 degrees Celsius (3.6 to 7.2 degrees Fahrenheit) and sea levels were higher by roughly 20 meters (almost 66 feet) than today, explained Kevin D. Burke, lead author of the study and a researcher and Ph.D. candidate at the Nelson Institute for Environmental Studies at the University of Wisconsin-Madison.

Today is "one of the most difficult scenarios we've ever found ourselves in," Burke said. "This is a very rapid period of climatic change. Looking for anything that we can do to curb those emissions is important."

Climate scientists say that our globe is about 1 degree Celsius hotter today than it was between 1850 and 1900 and that this is due in part to gas emissions from cars, planes and other human activities. Some gases, including carbon dioxide and methane, trap heat in the atmosphere, producing a " greenhouse effect" that makes the planet warmer.

lakewoodhiker on December 11st, 2018 at 18:41 UTC »

I attend a lot of ice/climate/goesciences conferences and still remember a few years back when I was sitting at talk being presented by a good friend and collaborator of mine. He was talking about his temperature reconstruction that he developed using data from a specific Antarctic Ice core that we had both worked on. I've spent enough time in this field now, where it's generally hard to really "shock" me, as it were. But I'll never forgot as he was going through his slides he said, in effect,

"Because of this warming trend of XXXX Degrees over the last 100 years, we have permanently eliminated the possibility that we will progress into the next glacial cycle."

You see...for the last few million years we've been on a orbitally-driven cycle of very-regular glacial/interglacial periods. But...we have altered the climate and atmospheric concentration of greenhouse gases so drastically, that the next glacial cycle will no longer be able to initiate. We truly have begun the Anthropocene period. I had already known this, but hearing him say it so matter-of-factly at large conference if front of so many established scientists was quite sobering.

antgweb on December 11st, 2018 at 16:48 UTC »

So the first primates evolved during the last big warming (PETL I think). I understand there were forests at the poles. Wonder what'll happen to us?

geeves_007 on December 11st, 2018 at 15:33 UTC »

As I’ve followed the increasingly extreme and concerning articles on climate change, and one question always enters my mind:

If humanity came together across nations and collaborated to drastically reduce GHG emissions and plastics and other obvious major drivers of this problem, how quickly (or at all?) would this trend reverse?

Imagine a complete global prohibition on coal burning, for example. Starting Jan 1, 2019. Any nation caught using coal is immediately subject to crushing international sanctions, trade embargoes and possibly military consequences (i.e. the UN procures an arsenal of cruise missiles and if you have a coal plant, you get a 24hr warning to evacuate your people, and boom we destroy it).

Obviously this fantasy scenario would require global cooperation and agreement on the seriousness of this problem, and the justification for extreme action.

But if we did something THAT extreme - as a species, would climate change slow and/or reverse just as fast as it came?