Dire warning: Earth may have crossed climate 'tipping points'
We're heading toward an unstoppable cascade of climate events that poses an "existential threat to civilization," scientists say.
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Jackson Ryan was CNET's science editor, and a multiple award-winning one at that. Earlier, he'd been a scientist, but he realized he wasn't very happy sitting at a lab bench all day. Science writing, he realized, was the best job in the world -- it let him tell stories about space, the planet, climate change and the people working at the frontiers of human knowledge. He also owns a lot of ugly Christmas sweaters.
"A decade ago we identified a suite of potential tipping points in the Earth system, now we see evidence that over half of them have been activated," said Tim Lenton, a climate scientist at the University of Exeter and lead author of the piece, in a press release.
The commentary piece says these events might unfold at a much more rapid pace than previously believed, with complex feedback loops causing a cascade of effects. For instance, losing the Arctic ice sheet might increase the risk of slowing down Atlantic circulation, which helps transport heat and salt around the oceans. As the Arctic sheet melts, the circulation slows... and if the circulation slows, the Amazon may be affected, as might Antarctic sea loss. Part of this process may already have begun.
It's a dire warning from the experts, tying together a wide range of evidence that humans are rapidly approaching some of the previously identified tipping points.
"In our view, the evidence from tipping points alone suggests that we are in a state of planetary emergency: both the risk and urgency of the situation are acute," the authors write.
The researchers agree it is difficult to understand the full extent of the interplay between Earth's myriad of climate-affected systems. But they note that carrying on with the business-as-usual approach will still put us on track for approximately 3 degrees of warming. Notably, the authors highlight that Earth's climate has been unstable across timescales before, caused by small changes in Earth's orbit. However, now humans are "strongly forcing the system" into a state that hasn't been seen for millions of years.
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