Is it really 12, 11, or even 10 years left?

“What Does ’12 Years to Act on Climate Change’ (Now 11 Years) Really Mean?

“It doesn’t mean the world can wait until 2030 to cut greenhouse gas emissions, or that chaos will erupt in 2030. Here’s what the science shows.

Full Article Link Inside Climate News

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“We’ve been hearing variations of the phrase “the world only has 12 years to deal with climate change” a lot lately…

“All this work gets summarized as ‘in order to avoid really bad outcomes, we have to be on a realistic glide path toward a carbon-free global economy by 2030.’ And that gets translated to something like ’emissions have to fall by half in a decade,’ and that gets oversimplified to ’12 years left.’

“There’s certainly a grain of truth in the phrase, but it’s so oversimplified that it leads to comically bad misconceptions about how to get there, conjuring up ridiculous cartoon imagery suggesting we just go on with life normally for the next 11 years and then the world ends,” Denning said.

“That’s not what the IPCC writers envisioned, he said.

“The science on the 2030 date is clear, said Michael Mann, a climate scientist at Pennsylvania State University. The controversy stems from people mischaracterizing the carbon reduction timeline as a threshold for climate disaster. He noted that people promoting climate science denial and delay have also latched on to the phrase “to intentionally try to caricature the concern about climate change.”

“But where does the idea of having 11 or 12 years come from, and what does it actually mean?

“The number began drawing attention in 2018, when the United Nations’ Intergovernmental Panel on Climate Change released a report describing what it would take to keep global temperatures from rising more than 1.5 degrees Celsius, a goal of the Paris climate agreement. The report explained that countries would have to cut their anthropogenic carbon dioxide emissions, such as from power plants and vehicles, to net zero by around 2050. To reach that goal, it said, CO2 emissions would have to start dropping “well before 2030” and be on a path to fall by about 45 percent by around 2030 (12 years away at that time)…

“We need to get the world on a path to net zero CO2 emissions by mid-century,” Shindell said. “That’s a huge transformation, so that if we don’t make a good start on it during the 2020s, we won’t be able to get there at a reasonable cost.”

“How Do Scientists Know?

“Basics physics and climate science allow scientists to calculate how much CO2 it takes to raise the global temperature—and how much CO2 can still be emitted before global warming exceeds 1.5°C (2.7°F) compared to pre-industrial times.

“Scientists worked backward from that basic knowledge to come up with timelines for what would have to happen to stay under 1.5°C warming, said Scott Denning, who studies the warming atmosphere at Colorado State University.

“They figured out how much extra heat we can stand. They calculated how much CO2 would produce that much heat, then how much total fuel would produce that much CO2. Then they considered ‘glide paths’ for getting emissions to zero before we burn too much carbon to avoid catastrophe,” he said.

“All this work gets summarized as ‘in order to avoid really bad outcomes, we have to be on a realistic glide path toward a carbon-free global economy by 2030.’ And that gets translated to something like ’emissions have to fall by half in a decade,’ and that gets oversimplified to ’12 years left.’

“There’s certainly a grain of truth in the phrase, but it’s so oversimplified that it leads to comically bad misconceptions about how to get there, conjuring up ridiculous cartoon imagery suggesting we just go on with life normally for the next 11 years and then the world ends,” Denning said.

That’s not what the IPCC writers envisioned, he said.

The science on the 2030 date is clear, said Michael Mann, a climate scientist at Pennsylvania State University. The controversy stems from people mischaracterizing the carbon reduction timeline as a threshold for climate disaster. He noted that people promoting climate science denial and delay have also latched on to the phrase “to intentionally try to caricature the concern about climate change.”


We provide the Full Article Link, but do not try to make the whole article ours.  It does not belong to us. We only give you a flavour of it, so you can make up your own mind if you like and want to support the award-winning journalism behind it, like we do. Of course, we do not or could support all the points made in any article we highlight, but that is part of living in a democracy.  We believe the material is relevant to all and is necessary for their personal judgments.


 

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