The 2025 Global Carbon Budget projects 38.1 billion tonnes of fossil carbon dioxide (CO2) emissions this year. With projected emissions from land-use change (such as deforestation) down to 4.1 billion tonnes in 2025, total CO2 emissions are projected to be slightly lower than last year.
This year’s report – published alongside a new paper in the journal Nature – examines the impact of climate change on the land and ocean carbon sinks. It finds that 8% of the rise in atmospheric CO2 concentration since 1960 is due to climate change weakening the land and ocean sinks.
The report, due to be launched at COP30 in Brazil on Thursday, 13 November, also concludes that the remaining carbon budget to limit global warming to 1.5°C is “virtually exhausted”.
Dr Patrick McGuire, of the University of Reading and National Centre for Atmospheric Science, participated in the Global Carbon Budget for a third consecutive year and for a fifth time in total. As in last year’s report, he evaluated and compared the various computer models that simulate how land ecosystems absorb and release carbon.
Dr McGuire said: “Decarbonisation efforts are advancing in many nations, but they’re being outpaced by rising global energy consumption. The harsh reality is that our carbon budget for 1.5°C is essentially spent. Without the sharp emissions reductions we desperately need, CO2 concentrations and climate impacts will continue their relentless rise.”
The Global Carbon Budget report, produced by an international team of more than 130 scientists, provides an annual, peer-reviewed update. The research team included was led by the University of Exeter, the University of East Anglia (UEA), CICERO Center for International Climate Research, Ludwig-Maximilian-University Munich (LMU), Alfred-Wegener-Institut and included contributions from more than 90 other global institutions, including the University of Reading and National Centre for Atmospheric Science.
Other key findings from the 2025 Global Carbon Budget include:
China’s emissions in 2025 are projected to increase by 0.4% – growing more slowly than in recent years, due to a moderate growth in energy consumption combined with an extraordinary growth in renewable energy.
India’s emissions are projected to increase by 1.4% – also slower than recent trends. An early monsoon reduced cooling requirements in the hottest months. Combined with strong growth in renewables, this led to very low growth in coal consumption.
Emissions are projected to grow in the USA (+1.9%) and the European Union (0.4%) in 2025. Emissions in these regions have declined in recent years, but colder weather and other factors led to an increase in 2025.
Projected emissions in Japan, provided this year for the first time, are down 2.2% in line with recent trends.
Emissions for the rest of the world are projected to increase by 1.1%.
The projected rise in fossil CO2 emissions in 2025 is driven by all fuel types: coal +0.8%, oil +1%, natural gas +1.3%.
Emissions are projected to increase by 6.8% for international aviation (exceeding pre-COVID levels) but to remain flat for international shipping.
Over the 2015-2024 period, emissions from permanent deforestation remain high at around 4 billion tonnes of CO2 per year, while permanent removals through re/afforestation and forest regrowth offsets about half of the permanent deforestation emissions.
Total CO2 emissions – the sum of fossil and land-use change emissions – have grown more slowly in the past decade (0.3% per year), compared to the previous decade (1.9% per year).
The remaining carbon budget to limit global warming to 1.5°C is virtually exhausted. The remaining budget for 1.5°C is 170 billion tonnes of CO2, equivalent to four years at the 2025 emissions levels.
The combined effects of climate change and deforestation have turned Southeast Asian and large parts of South American tropical forests from CO2 sinks to sources.
The concentration of CO2 in the atmosphere is set to reach 425.7 ppm in 2025, 52% above pre-industrial levels.
That 8% figure for how much climate change has weakened the carbon sinks since 1960 is pretty wild. Basically, we're not just fighting our own emissions anymore, we're also losing the natural systems that used to clean up after us. The land use shift in Southeast Asia and South America turning from sinks to sources really shows how this feedback loop is accelerating faster than most models predicted.