Relying on natural carbon sinks such as forests and oceans to offset continued fossil fuel emissions will not stop global warming, the scientists who developed net zero have warned.
Every year, the planet’s oceans, forests, soil and other natural carbon sinks absorb approx half of all human emissionswhich forms part of the government’s plans to limit global warming to below 2C under the Paris Agreement.
But the international group of authors developing the science behind net zero warned that countries could “cheat” their way to Paris targets by using natural parts of the Earth’s carbon cycle to make it look like they have achieved net zero when they continue to drive global warming. .
The study, Published in Nature on Monday and led by the University of Oxford, said that naturally occurring carbon sinks such as rainforests and peatlands should be protected so they can remove historical pollution, but never formed part of the original net zero definition developed by scientists in 2009.
The scientists stressed the need for “geological net zero,” meaning that any future carbon emissions must be offset by permanent removal of pollution from fossil fuels – not from pre-existing natural ecosystems. They urged governments to urgently clarify what net zero means policeman 29 in Azerbaijan or continue to risk catastrophic climate collapse.
The rules of the Paris Agreement allow countries to claim carbon removals from “managed land” in their territory in their targets towards the goal, such as parts of the Amazon rainforest in Brazil or the taiga forest in Russia. But the net zero researchers said that these rules allow countries to take credit for natural processes that have nothing to do with human emissions.
Conversely, emissions and removals from “unmanaged” land, such as such as the recent wildfires in Canada which emit CO2 equivalent to three times their annual footprint, are not factored into a country’s progress towards the targets.
“We need to protect passive carbon sinks. We need to protect our forests and oceans because we need them to provide that carbon sink service so that net zero emissions can actually do what we humans promise it will do, which is stop global warming. But we can’t pretend that those passive sinks somehow compensate for continued use of fossil fuels,” says Prof Myles Allen of the University of Oxford’s Department of Physics, who led the study.
“If you’re still using fossil fuels and still generating carbon dioxide from burning fossil fuels by mid-century, you need to have a plan to put the carbon dioxide they generate back underground or into an equally permanent storage,” he said. said.
Allen expressed concern that countries could even take credit for natural carbon removal from the ocean by claiming “managed oceans.”
“Perhaps you will find some countries using it deliberately in a mischievous way: ‘cheating’,” said Dr Glen Peters, of the Cicero Center for International Climate Research in Oslo, a co-author of the paper.
The study comes amid growing concern about the stability of Earth’s carbon sinks, which researchers say could temporarily collapse in 2023 amid record temperatures, an El Niño system and other pressures on ecosystems. The result was that forests, plants and soil – as a net category – absorbed almost no carbon, research found.
Analysis by the research organization Zero Carbon Analytics found that the role of nature in nationally determined contributions (NDCs) was a significant blind spot for governments that could make them appear closer than they were to achieving net zero.
An investigation into differences in how natural carbon sinks are accounted for in models and NDCs indicated that the budget to limit global warming to below 2C may be 15% to 18% smaller than thought. It also found that the amount of land designated for land-based carbon dioxide removal – such as tree planting – by governments was unrealistic.
“How land is classified in national climate commitments is a critical blind spot in carbon accounting. This allows large releases from wildfires and natural forest disturbances to remain uncounted, ultimately misrepresenting progress towards climate goals… Impressive sounding national climate plans do not always reflect true progress,” says Joanne Bentley, who runs the analysis led Zero. Carbon analysis.
“It is particularly problematic when governments rely too much on forests to absorb emissions instead of making the immediate large-scale changes to industries that are urgently needed,” she said.
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