‘Uncertain’ net zero rules threaten climate targets, scientists warn

Countries don’t have to count the carbon dioxide naturally absorbed by Earth’s forests toward their net zero. climate plans, scientists said Monday, warning that “uncertain” rules could lead to greater than expected global warming.

Scientists who developed the original science behind net zero issued a warning in a new study as countries gathered in Azerbaijan for the latest round of UN climate talks.

The world’s oceans, forests and soil absorb planet-warming carbon dioxide from the atmosphere, meaning they play a critical role in efforts to prevent temperatures from rising further.

These “natural carbon sinks” currently absorb about half of all carbon dioxide emitted by humanity.

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Under the Paris Climate Agreement, countries pledged to limit global warming to 1.5 degrees Celsius compared to pre-industrial times.

While they haven’t specified how they plan to achieve this goal, scientists say the world needs to cut emissions by nearly half this decade and reach net zero – when humanity no longer emits more greenhouse gases than it captures – by 2050.

Once emissions drop to near zero, forests and oceans will be able to absorb some of the extra carbon dioxide that has accumulated in the atmosphere so that global temperatures can “stabilize,” said Miles Allen, a scientist at the University of Oxford and lead author of the study. study in the journal Nature.

Allen helped develop the science behind net zero in the 2000s.

But there was a problem because it “didn’t occur to me at the time,” he said at a news conference.

When countries announced their climate plans, some said the amount of carbon naturally removed by their forests and land would offset some of the emissions from their populations and industries.

But natural carbon sinks can’t be counted on to “do two things at once,” Allen said.

“If we’re going to count on them to eliminate our historical emissions … we can’t at the same time use them to offset future fossil fuel emissions.”

This may seem like a small change in greenhouse gas accounting, but it could mean the world thinks it is on track to limit warming to 1.5°C, when in fact it could exceed 2°C, “and warming will continue and in the future”. – he said.

Russia, for example, “seems to have recently indicated that they can just get to net-zero emissions while increasing their use of fossil fuels because they have such large forests,” Allen said.

The European Union recently began partially claiming that the operation of its forests offsets emissions, said Glen Peters, research director at the Center for International Climate Research in Oslo.

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It’s not that countries are breaking the rules, Allen said: “It’s just that the rules are a little vague.”

Most countries and many large companies have announced some kind of net zero plan, but the details of how and when they will be implemented vary widely, compromising their integrity, experts warn.

Researchers have called on the world to focus on “geological net zero”, which would mean that for every ton of carbon dioxide released by fossil fuels – the main source of emissions – would need to be sucked out of the atmosphere and permanently buried back in the ground.

While there are hopes of a boom in technologies that extract CO2 from the air, only 0.1% of carbon dioxide emissions are currently captured and sequestered, a figure that needs to be increased to 100% by mid-century, Allen said.

Peters added: “If you don’t get fossil fuels out of the ground at all, you’re still a long way from solving the problem.”

Last week it was predicted that humanity will again break the record carbon dioxide emissions in 2024, which is expected to be the hottest year in human history.