In 2023, global land carbon sinks, including forests, soils, and vegetation, saw a sharp decline in their capacity to absorb CO2, as highlighted by a study in 'National Science Review'. The collaborative research, involving global teams, employed dynamic vegetation models, satellite fire emission data, OCO-2 satellite observations, and ocean model emulators for a comprehensive carbon budget assessment.
Philippe Ciais, from the French Laboratory of Climate and Environmental Sciences and co-author of the paper, noted, "In 2023 the accumulation of CO2 in the atmosphere is very high and this translates into a very, very low absorption by the terrestrial biosphere." He added that the northern hemisphere, responsible for over half of the CO2 uptake, has shown a declining absorption trend over the past eight years, cautioning, "There is no good reason to believe it will bounce back."
The 2023 data indicates that land carbon sink absorption decreased to 0.44 +/- 0.21 GtC yr-1, impacted by extreme heat, widespread wildfires, and a moderate El Nino. Notably, Canadian wildfires contributed approximately 0.58 +/- 0.10 GtC, with an additional 0.31 +/- 0.19 GtC loss due to Amazon drought conditions.
While ocean carbon sinks experienced a slight increase of 0.10 GtC yr-1 compared to the previous year, attributed mainly to El Nino effects in the Pacific Ocean that suppressed CO2 emissions, the abrupt decrease in land sink raises alarms for climate stability. The study points out that current climate prediction models may not sufficiently capture such sudden declines in carbon sinks.
Researchers emphasize the urgent need for global measures to safeguard and bolster carbon sinks, combined with significant cuts in fossil fuel emissions, to mitigate further climate risks.
Research Report:Low latency carbon budget analysis reveals a large decline of the land carbon sink in 2023
