November 19, 2024
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Trees alone cannot stop climate change
Forests absorb planet-warming pollution, but world leaders shouldn’t include it in plans to net greenhouse gas emissions, a new study recommends.
Beech Forest in early spring.
KLIMAWIRE | Countries around the world have turned to natural carbon sinks, such as forests and wetlands, to help meet their climate goals. It is thought that these landscapes naturally absorb carbon dioxide from the atmosphere and therefore can stop the continuous emissions of fossil fuels.
But that kind of approach is a mistake, say some of the world’s leading scientists new exam. And it could jeopardize the fragile climate goals of the Paris Agreement.
Because carbon dioxide lingers in the atmosphere for decades, forests and other natural carbon sinks are still absorbing emissions from humans many years ago. And that carbon doesn’t stay in the ground forever either. It becomes part of the Earth’s natural carbon cycle, eventually escaping into the atmosphere when trees die, before being reabsorbed by another natural landscape.
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It’s all part of a huge natural balance. But the system remains in balance as long as emissions from human sources drop to zero. If humans depend on natural carbon sinks to balance future emissions, the world will continue to warm.
That’s the stark conclusion of research published Monday in the scientific journal nature
“We’re already counting on forests and oceans to clean up our past emissions, most of which come from burning things that come out of the ground,” lead study author Myles Allen, a climate scientist at the University of Oxford, said in a statement. . “We can’t expect them to offset future emissions either.”
Countries around the world have submitted carbon-cutting pledges to the United Nations in an effort to meet the Paris Agreement’s two main climate goals: keeping global warming below 2 degrees Celsius and, if possible, below the ambitious 1.5 C.
Scientists warn that global emissions must reach zero by mid-century for the world to stay close to the 1.5C target, meaning that every carbon entering the atmosphere must be balanced by the same amount of carbon leaving.
But these offsets must be sustainable, say scientists, and should not come from sources that are part of the natural carbon cycle. To truly stop global warming, world leaders must offset residual fossil fuel emissions by capturing that carbon and storing it in geological reservoirs underground, where it cannot escape.
It’s a concept the authors call “geological net zero,” and it’s increasingly urgent, they say.
The issue is based on the rules of the Paris Agreement, which does not require countries to separate passive carbon sinks, such as forests, from zero targets. Many nations have already begun to use these natural landscapes in their net-zero accounting systems, suggesting that the forests within their national borders are offsetting some of their fossil fuel emissions.
More than 6.5 billion metric tons of passive carbon sinks each year are classified as carbon removals in the national emissions inventories that countries submit to the United Nations, the study says. This means world leaders are using it to count against fossil fuel emissions, helping them reach net zero faster.
The system doesn’t have to work that way.
Take the Kyoto Protocol, the UN climate treaty adopted in 1997. The agreement did not meet its climate goals, but it contained some useful provisions, the authors of the study noted. The agreement recommended that nations use passive carbon sinks, such as forests, in their emissions accounting systems.
New research suggests the problem with Paris’ accounting system needs wider awareness.
“Achieving and maintaining ‘net zero’ emissions under accounting rules that allow passive CO2 uptake to be counted as CO2 removal will slow global warming,” the authors said.
Reprinted E&E News Courtesy of POLITICO, LLC. Copyright 2024. E&E News provides essential news for energy and environmental professionals.
