Experts are ignoring the worst possible disaster scenarios for climate change, including the collapse of society or potential human extinction, no matter how unlikely, a group of top scientists has claimed.
Eleven scientists from around the world are asking the UN’s Intergovernmental Panel on Climate Change, the world’s authoritative climate science organization, to create a special science report on “catastrophic climate change” to “focus on how much is at stake in a worst-case scenario.” In their perspective piece on Monday In the Proceedings of the National Academy of Sciences, they address the idea of human extinction and worldwide societal collapse in the third sentence, calling it “a dangerously underexplored topic.”
The researchers said they are not saying the worst is going to happen. They say the problem is that no one knows how likely or unlikely a “climate endgame” is, and that the world needs these calculations to fight global warming.
“I think it’s very unlikely that you’re going to see anything close to extinction in the next century, just because humans are incredibly resilient,” said study leader Luke Kemp of the Center for the Study of Existential Risk at the University of Cambridge in England. . “Even if we have a 1% chance of having a global catastrophe, which will be eradicated in the coming century, that 1% is way too high.”
Catastrophic climate scenarios “look likely enough to warrant attention” and could lead to prevention and warning systems, Kemp said.
Good risk analyzes consider both what is most likely and what is the worst that could happen, study authors said. But because of pushback from non-scientists who deny climate change, mainstream climate science has concentrated on looking at what is most likely and also disproportionately at low-temperature warming scenarios that approach international targets, said co-author Tim Lenton, director of the Global Systems Institute at the University of Exeter in England.
There is, Lenton said, “not enough emphasis on how things, the risks, the big risks, could plausibly go wrong.”
It’s like an airplane, Lenton said. It’s overwhelmingly likely that it will land safely, but that’s only because so much care was taken to calculate the worst-case scenario and then figure out how to avoid a crash. It only works if you examine what can go wrong, and not enough is being done about climate change, he said.
“The stakes may be higher than we thought,” said University of Michigan environment dean Jonathan Overpeck, who was not part of the study. He worries that the world “could stumble” over climate risks it doesn’t know about.
When global scientific organizations look at climate change, they tend to look only at what is happening in the world: extreme weather, higher temperatures, melting ice sheets, rising seas and the extinction of plants and animals. But they do not take enough account of how these resonate in human societies and interact with existing problems – such as war, hunger and disease – study authors said.
“If we don’t look at the intersecting risks, we will be painfully surprised,” said University of Washington public health and climate professor Kristie Ebi, a co-author who, like Lenton, has been part of the United Nations’ global climate assessments.
That was a mistake health professionals made before COVID-19 when they were assessing possible pandemics, Ebi said. They talked about the spread of disease, but not shutdowns, supply chain problems and spiraling economies.
Study authors said they worry about societal breakdowns — war, famine, economic crises — linked to climate change more than the physical changes on Earth itself.
Outside climate scientists and risk experts were both receptive and wary of focusing on the worst of the worst, even though many reject climate doom.
“I don’t think civilization as we know it will make it out of this century,” University of Victoria climate scientist Andrew Weaver, a former British Columbia legislator for the Green Party, said in an email. “Resilient people will survive, but our societies that have urbanized and are supported by agriculture will not.”
Climate scientist Zeke Hausfather of the technology company Stripe and Berkeley Earth has previously criticized climate scientists for using future scenarios of sharply increasing carbon pollution when the world is no longer on these paths to faster warming. Still, he said it makes sense to look at catastrophic scenarios “as long as we’re careful not to conflate the worst case with the most likely outcome.”
Talking about human extinction is not “a very effective communication device,” said Brown University climate scientist Kim Cobb. “People tend to immediately say, well, it’s just, you know, arm-waving or doomsday mongering.”
What happens before extinction is bad enough, she said.
Co-author Tim Lenton said examining worst-case scenarios found nothing to worry about: “Maybe it’s that you can rule out a number of these bad scenarios. Well, it’s actually very well worth spending your time on. Then we should all cheer up a little.”
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