By AFP - Agence France Presse
COP29 - Azerbaijan
'Vague' net zero rules threaten climate goals, scientists warn
Daniel Lawler
Countries should not count the carbon dioxide naturally sucked up by the Earth's forests in their net-zero emissions climate plans, scientists said on Monday, warning that “vague” rules could cause the world to warm more than expected.
The scientists, who developed the original science behind net zero, issued their warning in a new study as nations 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, which means they play a crucial role in efforts to stop temperatures from rising further.
These “natural carbon sinks” currently absorb around half of all the carbon dioxide emitted by humanity.
In the Paris Climate Agreement, nations pledged to reduce global warming to 1.5 degrees Celsius above the pre-industrial era.
Although they didn't specify how they would achieve this target, scientists say the world needs to cut emissions by almost half this decade and reach net zero - when humanity will emit no more greenhouse gases than it captures - by 2050.
When emissions reach practically zero, forests and oceans should be able to absorb some of the additional carbon dioxides that have accumulated in the atmosphere so that global temperatures can “stabilize,” said Myles Allen, a scientist at Oxford University and lead author of the study published in the journal Nature.
Allen helped develop the science behind net zero in the 2000s.
But since then, a problem has arisen that “didn't occur to me at the time,” he told a press conference.
When nations announced their climate plans, some claimed that the amount of carbon removed naturally by their forests and land would offset some of the emissions from their inhabitants and industries.
But you can't rely on natural carbon sinks “to do two jobs at once,” Allen emphasized.
“If we're going to rely on them to absorb our historical emissions... we can't at the same time use them to offset future fossil fuel emissions.”
- Warming risk - It may seem like a small adjustment.
This may seem like a small adjustment in greenhouse gas accounting, but it could mean that the world thinks it is on track to limit warming to 1.5°C, when in fact, it could exceed two °C “and continue to warm in the future” he said.
Russia, for example, “apparently recently pointed out that it could reach net zero and at the same time increase fossil fuel use because it has such large forests,” Allen said.
The European Union has recently begun to partially claim the work of its forests as compensation for emissions, said Glen Peters, research director at the Center for International Climate Research in Oslo.
It's not that countries are breaking the rules, said Allen: “It's just that the rules are a bit vague.”
Most countries and many large companies have announced some kind of net zero plan, but the details of exactly how and when it will be carried out vary widely, threatening its integrity, experts warned.
- 'Geological net zero' - What does the world need to do?
The researchers called for the world to aim for “geological net zero,” which would mean that for every ton of carbon dioxide emitted by fossil fuel - the main source of emissions - one ton would need to be sucked out of the atmosphere and permanently put back into the ground.
Although 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 blocked - this needs to rise to 100% by the middle of the century, said Allen.
Peters added: “If you don't get fossil fuels out of the ground first, you're a long way from solving the problem.”
Last week, it was predicted that humanity would again break the record for carbon dioxide emissions in 2024, which is expected to be the hottest year ever recorded in history.
dl/klm/yad
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