in 2023, “carbon sinks” will have captured 25% of what they usually capture over a year

If 2023 was such a bad year, it is notably because of the severe drought in the tropics, explains one of the authors of the study, Philippe Ciais to France Inter.

Soils and forests, considered “carbon sinks”, only absorbed between 1.5 and 2.6 billion tonnes of CO2 last year, France Inter learned on Tuesday, July 30, a quarter of what they captured on average in previous years. A trend that worries the authors of the study that warns on this subject, including Philippe Ciais, research director at the French Alternative Energies and Atomic Energy Commission (CEA). In 2022, 9.6 billion tonnes of CO2 had been captured by vegetation.

The year 2023 has been “particularly bad, because we have the appearance of two factors at the same time”summarizes Philippe Ciais. “We have this drought in the tropics (especially in the Amazon) and in addition, we have had this continuous subsidence of the absorption of the forests of the northern hemisphere”caused in particular by megafires in Canada and Siberia. 2023 is therefore “a year that can alert us”notes the research director.

What is especially worrying is that the researcher does not imagine “a rapid recovery of absorption in the forests of the northern hemisphere, because they are now subject to droughts, to very frequent fires”The conclusion of this study, co-written by around fifteen researchers, is that there will be a drop in CO2 captures with each wave of drought in the tropics, “since the absorption in the northern hemisphere is somehow less good”And this “for several years in a row”, says Philippe Ciais. As a result, CO2 will increase faster in the atmosphere and accelerate global warming.

The world’s soils and forests normally absorb a quarter of human CO2 emissions, the oceans another quarter, and the rest accumulates in the atmosphere. 2023 was a record year for global temperatures: 1.48°C warmer than the pre-industrial era of 1850 to 1900.