Adding to the concerns about the way the world is handling climate change, the World Meteorological Organisation, external says that concentrations of greenhouse gases reached a record high in 2023.
The rise last year was higher than the previous 12 months, due to record fires in Canada, and the onset of the El Niño weather event all adding to ongoing emissions from fossil fuels.
But the WMO’s scientists also says they have seen some evidence that as the world gets warmer, trees are not able to soak up the same level of CO2 as they once were.
Data indicates that the southeastern Amazon has now turned from a carbon sink to a source.
“In the Amazon, deforestation means you lose the forest,” said Dr Oksana Tarasova from the WMO.
“Then the temperature started increasing, then the air circulation pattern changes. There is less precipitation, less uptake of CO2, that means more CO2 stays in the atmosphere.”
The Amazon is one example of what scientists call a climate feedback – where rising temperatures can act on natural systems to enhance the causes of warming.
So if the forests and the oceans become less able to soak up CO2, global warming could accelerate more rapidly.
“We do see some clear signals. We cannot say it’s 100% climate feedbacks because there’s substantial variability because of El Niño and La Niña weather events, but we are seeing something happening in the system,” said Oksana Tarasova.
The WMO says that the last time the Earth experienced a comparable concentration of carbon in the atmosphere was 3-5 million year ago – when average temperatures were 2-3C warmer than they are now, and sea levels were 10-20 metres higher.
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