November 19, 2024
3 minimum read
Trees alone cannot stop climate change
Forests absorb global warming pollution, but world leaders should not include them in plans to reach net-zero greenhouse gas emissions, new study recommends
Beech forest in early spring.
Climate Wire | Countries around the world are turning to natural carbon sinks such as forests and wetlands to help meet climate goals. These landscapes naturally absorb carbon dioxide from the atmosphere, which is thought to help offset continued emissions from fossil fuels.
But such an approach is wrong, some of the world’s leading scientists say in a new study. And that could jeopardize the Paris Agreement’s fragile climate goals.
Because carbon dioxide stays in the atmosphere for decades, forests and other natural carbon sinks are still absorbing emissions that humans released years ago. And that carbon doesn’t stay underground forever. It becomes part of the earth’s natural carbon cycle, eventually escaping into the atmosphere when trees die, and eventually being absorbed back into the rest of the natural landscape.
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It’s all part of a huge natural equilibrium. However, this system will remain balanced as long as emissions from human sources gradually reduce to zero. If humanity relied on natural carbon sinks to balance future emissions, the world would only continue to warm.
That’s the clear conclusion of a study published Monday in the journal Science. Nature.
“We’re already counting on forests and oceans to absorb past emissions, most of which come from burning what we dig out of the ground,” said the lead author of the study. said author Miles Allen, a climate scientist at the University of Oxford, in a statement. . “We also cannot expect to compensate for future emissions.”
Countries around the world will meet the two key climate goals of the Paris Agreement: limiting global warming to below 2 degrees Celsius and, if possible, to the more ambitious 1.5 degrees Celsius. To this end, we have submitted a carbon reduction pledge to the United Nations.
Scientists have warned that global emissions need to reach net zero by mid-century to keep the world moving towards the 1.5 degrees target. This means that the carbon emitted into the atmosphere must be balanced by an equal amount of carbon returned.
But these offsets need to be permanent and cannot come from sources that are already part of the natural carbon cycle, scientists say. To actually stop global warming, world leaders need to offset remaining fossil fuel emissions by capturing fossil fuel carbon and sequestering it in underground geological formations where it cannot escape. be.
This is a concept the authors call “geological net zero,” and they say it is becoming increasingly urgent.
The issue hinges on the rules of the Paris Agreement, which does not require countries to decouple passive carbon sinks such as forests from net-zero targets. Many countries have already begun to exploit these natural landscapes in their net-zero accounting regimes, suggesting that forests within their borders offset some of their fossil fuel emissions.
The study points out that more than 6.5 billion tonnes of carbon dioxide from passive carbon sinks is classified as carbon removal each year in the national emissions inventories that countries submit to the United Nations. This means world leaders are using them to count fossil fuel emissions and help us reach net zero faster.
There is no need for the system to work this way.
Take, for example, the Kyoto Protocol, the United Nations climate change treaty adopted in 1997. Although the agreement failed to meet climate goals, the study authors noted that it had some useful provisions. The agreement prevented countries from using passive carbon sinks such as forests in their emissions accounting systems.
New research suggests that broader awareness of the problems with the Paris accounting system is needed.
The authors said, “Achieving and maintaining ‘net zero’ emissions under accounting rules that allow passive CO2 absorption to be counted as CO2 removal will only slow global warming.”
Reprinted from E&E News Published with permission of POLITICO, LLC. Copyright 2024. E&E News provides news that matters to energy and environment professionals.
