The 2025 Global Carbon Budget projects 38.1 billion tonnes of fossil carbon dioxide (CO2) emissions this year. This is a 1.1% rise for 2025, reaching an all-time record high.

Decarbonisation of energy systems is progressing in many countries, but it is not enough to offset the growth in global energy demand.

With no sign of the urgently needed decline in global emissions, the level of CO2 in the atmosphere continues to rise, and so do the dangerous impacts of global warming.

With projected emissions from land‑use change (such as deforestation) down to 4.1 billion tonnes in 2025, total CO2 emissions are expected to be slightly lower than in 2024.

CO2 emissions budget beyond 2025

The new report says the remaining carbon budget to limit global warming to 1.5°C is “virtually exhausted”.

“With CO2 emissions still increasing, keeping global warming below 1.5°C is no longer plausible,” said Professor Pierre Friedlingstein, of Exeter’s Global Systems Institute, who led the study.

“The remaining carbon budget for 1.5°C, 170 billion tons of carbon dioxide, will be gone before 2030 at current emission rate. We estimate that climate change is now reducing the combined land and ocean sinks – a clear signal from Planet Earth that we need to dramatically reduce emissions.”

Carbon sinks under strain

2025’s report, published alongside a new paper in 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.

With the end of the 2023‑24 El Niño weather pattern – which causes heat and drought in many regions – the land “sink” (absorption of CO2 by natural ecosystems) has recovered this year to pre‑El Niño 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.

“Efforts to tackle climate change are visible, with 35 countries succeeding in reducing their emissions while growing their economies, twice as much as a decade ago, and important progress in reducing reliance on fossil fuels elsewhere,” explained Professor Corinne Le Quéré, Royal Society Research Professor at UEA’s School of Environmental Sciences.

“Progress is still much too fragile to translate into the sustained decreases in global emissions needed to tackle climate change. The emerging impacts of climate change on the carbon sinks is worrying and stresses further the need for urgent action.”

Where emissions are changing

China’s emissions in 2025 are projected to increase by 0.4%, growing more slowly than in recent years due to moderate growth in energy consumption combined with 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.

These factors, together with strong growth in renewables, led to minimal 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 are projected to cause an increase in 2025.

Japan’s projected emissions, 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%.

“It is 10 years since the Paris Agreement was negotiated, and despite progress on many fronts, fossil CO2 emissions continue their relentless rise,” noted Glen Peters, Senior Researcher at the Center for International Climate Research (CICERO).

“Climate change and variability are also having a discernible effect on our natural climate sinks. It is clear countries need to lift their game. We now have strong evidence that clean technologies help reduce emissions while being cost effective compared to fossil alternatives.”

Land use, fuels, and sectors

The projected rise in fossil CO2 emissions in 2025 is driven by all fuel types: coal up 0.8%, oil up 1.0%, and natural gas up 1.3%.

Emissions are projected to increase by 6.8% for international aviation (exceeding pre‑COVID levels) while remaining flat for international shipping.

Over the 2015–2024 period, emissions from permanent deforestation remained high, at around 4 billion tonnes of CO2 per year.

At the same time, permanent CO2 removals through reforestation and afforestation and forest regrowth offset about half of those 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).

Lessons from 2025 CO2 emissions

“The reduction in land-use emissions demonstrates the success that environmental policies can achieve. Deforestation rates in the Amazon have declined and are at their lowest level this season since 2014,” concluded Professor Julia Pongratz, at LMU’s Department of Geography.

“Yet the sweeping fires in 2024 revealed how sensitive the ecosystem remains if we don’t also limit global warming.”

The concentration of CO2 in the atmosphere is set to reach 425.7 ppm in 2025, 52% above pre‑industrial levels. The remaining budget for 1.5°C is equivalent to four years at the 2025 emission levels.

The full study was published in the journal Nature.