Global forests failed to limit climate emissions by 2023, study finds, World News

SAO PAULO — Forests and other land ecosystems will fail to combat climate change by 2023 as intense drought in the Amazon rainforest and record wildfires in Canada hampered their natural ability to absorb carbon dioxide, a study presented on July 29 found.

That means a record amount of carbon dioxide will have entered Earth’s atmosphere in 2023, further fueling global warming, the researchers said.

Plants help slow climate change by absorbing vast amounts of carbon dioxide, the main greenhouse gas that causes global warming. Forests and other land ecosystems absorb, on average, nearly a third of annual emissions from fossil fuels, industry and other human causes.

But by 2023, that carbon sink had collapsed, said study co-author Philippe Ciais of France’s Laboratory for Climate and Environmental Sciences (LSCE).

“The sink is a pump, and we’re pumping less carbon from the atmosphere into the land,” Dr. Ciais said in an interview. “Suddenly, the pump chokes, and it’s pumping less.”

As a result, the amount of carbon dioxide in the atmosphere increased by 86 percent in 2023 compared to 2022, the researchers said.

Scientists from Tsinghua University in China, the University of Exeter in England and LSCE led the investigation into the cause of the shift. Their study was presented at the International Carbon Dioxide Conference in Manaus, Brazil.

A major factor was record-high global temperatures, which dried out vegetation in the Amazon and other rainforests, preventing them from absorbing carbon and sparking record fires in Canada, the study found.

“Imagine your plants at home: if you don’t water them, they’re not very productive, they’re not growing and they’re not taking up carbon,” said Dr Stephen Sitch, co-author of the study and a carbon expert at the University of Exeter.

“Put that on a large scale, like the Amazon rainforest,” Dr Sitch told Reuters on the sidelines of the conference

The study is still being reviewed by a scientific journal, but three scientists not involved in the research told Reuters its conclusions are solid.

They said declines in land carbon sinks typically occur in years influenced by the El Niño climate phenomenon, such as 2023. But record high temperatures caused by climate change made the 2023 decline particularly extreme.

Moreover, the consequences of the decline are more severe than in the past, because humans are now emitting more carbon dioxide than ever before.

The scientists cautioned that Earth’s carbon sink varies greatly from year to year, and that a single year won’t spell doom. But it would be alarming if what was observed in 2023 became a trend, they added.

“This is a warning sign,” said Dr Richard Birdsey of the Woodwell Climate Research Centre in the US, who was not involved in the study. “There is a good chance that years like 2023 will become more common.”

The less carbon land ecosystems absorb, the fewer fossil fuels the world can burn before humanity exceeds global climate goals, said Dr Anthony Walker, an ecosystem modeller at Oak Ridge National Laboratory in the US who was not involved in the study.

“We can’t count on ecosystems to save us in the future,” said Dr. Trevor Keenan, an ecosystem scientist at the University of California, Berkeley, who was not involved in the study.

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