Fossil CO2 emissions reach record high

Regionally, the trends varied greatly: Whereas fossil emissions increased in India and China (+8.2% and + 4.0%), they fell in Europe and the United States (-7.4% and -3.0%) and decreased marginally in the rest of the world (-0.4%). The authors attribute the decline in Europe to the expansion of renewables and the effects of the energy crisis. Meanwhile, they attribute the growth in China partly to delayed recovery from the effects of the Covid-19 lockdowns.

Global CO₂ emissions a long way off the reductions needed

Adding in emissions from land use, the report finds that global carbon dioxide emissions will amount to some 40.9 billion metric tons in 2023. This is a long way off the significant reductions that are needed to reach the Paris Agreement climate goals, say the authors. Although the estimates for the remaining carbon budget come with substantial uncertainties, it is clear nevertheless that time is running out fast: If current levels of carbon dioxide emissions continue, the remaining carbon budget for a 50% chance of limiting warming to 1.5°C could be used up in seven years, and of limiting warming to 1.7°C in 15 years. “It now looks inevitable that we will overshoot the 1.5°C target – while the last few years have made it evident how serious the consequences of climate change already are. The world leaders at the climate conference in Dubai must commit to much greater efforts on emissions reductions if we are to at least meet the 2°C target,” says Julia Pongratz, Professor of Physical Geography and Land Use Systems at LMU.

Budget includes carbon removals for first time

“Although emissions from deforestation fell slightly, they are still too high to be counterbalanced by reforestation and afforestation,” says Clemens Schwingshackl, who was responsible alongside Pongratz for estimating land use emissions in the GCP report. Currently, around half of emissions from deforestation are offset by CO₂ uptake through re- and afforestation. Technical solutions such as Direct Air Capture with Carbon Storage (DACCS), which work independently of vegetation, are currently removing a negligible amount of carbon dioxide from the atmosphere. “For reaching the net-zero emissions targets, massive efforts to reduce emissions are essential first and foremost. To offset emissions that are hard to avoid, a strong expansion of carbon removal technologies will further be necessary,” says Schwingshackl.

El Niño makes presence felt

For 2023, the scientists estimate that around half the emitted carbon dioxide will be absorbed by carbon sinks on land and in the ocean. The remainder will enter the atmosphere, causing CO₂ concentrations to rise to an annual mean value of around 419 ppm (parts per million).

In relation to land sinks, the authors surmise that the El Niño warming phase, which began in mid-2023, is already having an effect. They predict that land sinks will absorb 10.4 billion metric tons of carbon dioxide in 2023. This figure is well down on previous years, where land sinks absorbed 12.3 billion metric tons on average. “In El Niño years, land sinks become weaker because regions such as the Amazon and Southeast Asia are affected by droughts and fires,” says Pongratz. The ocean reacts in opposite fashion, although variations are less pronounced from year to year than on land. After the unusual three consecutive La Niña years from 2020 to 2022, in which the ocean sinks did not increase, it is predicted that the uptake of carbon dioxide by the world’s oceans will increase again in 2023 to 10.6 billion metric tons.

The scientists expect that El Niño’s influence on carbon sinks on land and in the ocean will intensify over the coming months and will lead to stronger net growth of atmospheric carbon dioxide values in 2024.

Compiled by an international team of over 120 scientists, the Global Carbon Budget report provides an annual update of the current state of the carbon cycle. It is verified by experts, based on peer-reviewed methods, and fully transparent. This year’s report will be unveiled on 5 December at a press conference as part of the 28th UN Climate Conference in Dubai, where representatives from over 200 countries will meet to discuss the implementation of the Paris Agreement.

Many scientists from the German-speaking world were involved in the report. Hailing from the Alfred Wegener Institute (Bremerhaven), ETH Zurich, the GEOMAR Helmholtz Centre for Ocean Research (Kiel), the International Institute for Applied Systems Analysis (IIASA), Karlsruhe Institute of Technology, the Leibniz Institute for Baltic Sea Research (Warnemünde), Ludwig-Maximilians-Universität München (LMU Munich), the Max Planck Institute for Meteorology (Hamburg), the Max Planck Institute for Biogeochemistry (Jena), the Potsdam Institute for Climate Impact Research, and the University of Bern, these researchers contributed with ocean observations, model simulations of ocean, land, and atmosphere, and various analyses.