Key UN findings widely misinterpreted

A key finding in the latest IPCC climate report has been widely misinterpreted, according to researchers involved in the study.

In the document, researchers wrote that greenhouse gases are expected to peak “by 2025 at the latest”.

This means that carbon can rise for another three years and that the world can still avoid dangerous warming.

But scientists say it is wrong and that emissions should drop immediately.

The IPCC’s latest report focused on how to limit or limit emissions of the gases that are the main cause of warming.

In their summary to policy makers, the researchers said it was still possible to avoid the most dangerous levels of warming by keeping the rise in global temperatures below 1.5 C in this century.

This will require a major effort, where carbon emissions will have to shrink by 43% by the end of this decade to stay below this hazard limit.

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But before they fall, emissions must reach a peak – and it is in the text that explains this idea that the report becomes confusing.

“Global greenhouse gases are expected to peak between 2020 and by 2025 at the latest in global modeled roads that limit warming to 1.5 C,” the summary states.

Most media including the BBC concluded that this meant that emissions could increase until 2025 and that the world could still stay below 1.5C.

“When you read the text as it is laid out, it gives the impression that you have reached 2025, which I think is a very unfortunate result,” says Glen Peters, from the Center for International Climate Research in Oslo, and an IPCC . lead author.

“It’s an unfortunate wording choice. Unfortunately, it will potentially have some pretty negative consequences.”

So what went wrong?

This is partly because the climate models that researchers use to project temperatures work in five-year blocks, so 2025 follows, for example, 2020 without reference to the years between.

“Because models work at 5-year intervals, we cannot derive statements with higher precision,” said Dr. Joeri Rogelj, from Imperial College London, and an IPCC lead author.

“But when you look at the scientific data that support this headline, it immediately becomes clear that any scenario in line with 1.5C will reduce emissions from 2020 to 2025. Even for scenarios that limit warming to 2C, this is also the case. . “

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Another problem was timing.

Covid delayed the remediation report by about a year, but the information used came from models that were expected to peak roughly by 2020.

“The headline statement could not say that emissions should have already peaked, as governments and scientists need to agree on communications that are scientifically accurate without being binding on policy,” said Dr. Edward Byers, an IPCC contributing author from the International Institute for Applied Systems Analysis. .

This led to a long debate during the two-week approval session between scientists and officials about the exact words to be used.

“There was a lot of discussion about whether words like ‘now’ or ‘immediately’ can be used,” said Dr. Byers.

“Some parties or individuals were worried that this would soon become obsolete. And if the report was read in the future, ‘immediately’ means nothing.”

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“I personally do not agree with that, so I think ‘immediately’ would have been the best word to use.”

A major challenge in disseminating complex messages about climate change is that the more simplified media reports on these events often have a greater impact than science itself.

This worries observers who argue that it would be a disaster for the world to give countries the impression that emissions could continue to grow until 2025.

“We certainly do not have the luxury of letting emissions grow for another three years,” said Kaisa Kosonen of Greenpeace.

“We have eight years to almost halve global emissions. It’s a huge task, but still possible, as the IPCC has just reminded us – but if people now start chasing emissions in 2025 as a kind of benchmark, we do not have a chance.”

Follow Matt on Twitter @mattmcgrathbbc

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