The Global Carbon Project (GCP) is an international research project within the Future Earth research initiative on global sustainability, and a research partner of the World Climate Research Programme. It aims to develop a comprehensive assessment of the global carbon cycle, including both its biophysical and human dimensions, together with the interactions and feedbacks between them.

GCP releases the Global Carbon Budget (GCB) annually, consolidating various methodologies and quantifying carbon budgets. The Global Carbon Budget 2025 (GCB2025) is the 20th edition of the annual update, which started in 2006. In GCB2025, more than 140 scientists are involved, including scientists in Japanese institutes: National Institute for Environmental Studies (NIES), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Japan Meteorological Agency (JMA), Meteorological Research Institute (MRI), Institute of Applied Energy (IAE), and the University of Tokyo (UT). They contributed to GCB2025 using atmosphere/ocean observations and ocean flux mapping (JMA, MRI, NIES), an ocean biogeochemical model (MRI), an Earth System Model (JAMSTEC), land/ocean-atmosphere flux inversion models (NIES, JAMSTEC), and terrestrial biosphere models (IAE, UT).

Carbon budget for 2025

For the year 2025, fossil CO₂ emissions increased by 1.2% relative to 2024, with fossil emissions at 10.5 ± 0.5 GtC yr^-1 (including the cement carbonation sink, 0.2 GtC yr^-1), that from land-use change was 1.2 ± 0.7 GtC yr^-1, for total anthropogenic CO₂ emissions of 11.7 ± 0.9 GtC yr^-1 (42.8 ± 3.2 GtCO₂ yr^-1). Also, for 2025, the atmospheric growth rate was 4.4 ± 0.2 GtC yr^-1 (2.06 ± 0.1 ppm yr^-1), 3.6 GtC lower than the record high 2024 growth rate. The ocean sink was 3.2 ± 0.7 GtC yr^-1 and the global net uptake by the land was 3.6 ± 0.9 GtC yr^-1, with a small budget imbalance (0.5 GtC yr^-1). The global atmospheric CO₂ concentration averaged over 2025 reached 425.6 ± 0.1 ppm.

Preliminary estimate of carbon budget for 2026^*

Fossil CO₂ emissions are set to decrease in 2026 as clean energy expands and the Iran conflict reduces oil use

• Global fossil CO₂ emissions are projected to marginally decrease in 2026.
  The 0.4% decrease (range –1.5% to 0.6%) is driven by the growing deployment of clean energy along with a widespread decrease in oil emissions, likely a short-term response to the energy shock triggered by the Iran conflict.
• Solar and wind power and electric vehicles now offset about two-thirds of emissions from increasing energy demand.
  Further acceleration of clean technologies is needed for global fossil CO₂ emissions to peak and decline durably.
• Global CO₂ emissions from land-use change have decreased in the past decade, but are set to rise this year.
  The 2026 rise is driven by peat fires and forest degradation in Southeast Asia, associated with drier conditions linked to the onset of El Niño conditions.
• Total CO₂ emissions – the sum of fossil and land-use change emissions – have grown more slowly in the past decade compared to the previous decade.
  The average annual growth was 0.3% over 2016-2025, compared to 1.7% the previous decade.
• The remaining carbon budget to limit global warming to 1.5°C is virtually exhausted.
  With a warming of the planet attributed to human activities of 1.37°C in 2025, the remaining budget for 1.5°C is 150 GtCO₂ , equivalent to less than 4 years at the 2026 emissions levels.
• The land carbon sink has returned to its pre-El Niño levels after a severe weakening during the 2023-2024 event, with the effect of the current El Niño expected next year.
  The land and ocean have taken up 49% of total anthropogenic emissions in the past decade, but both sinks are negatively impacted by climate change.
• The concentration of CO₂ in the atmosphere is set to reach 427.7 parts per million in 2026, 54% above pre-industrial level.
  Atmospheric CO2 concentration is projected to grow by 2.2 ppm in 2026, further increasing the human influence on climate.

^* Derived from Key Messages released by Global Carbon Project. The press release is here.