CO₂ emissions hit a new record: the remaining budget to stay within 1.5°C is almost exhausted

The world moves forward like an engine that revs up just when the oil light turns red. It is the most precise image of the new global carbon budget: a system that accelerates while climate indicators signal that the margin of safety is almost over.

According to the Global Carbon Project, emissions from fossil fuels will rise by 1.1% in 2025, reaching a record 38.1 billion tonnes of CO₂. Decarbonisation is progressing in many countries, but is not keeping pace with a still growing energy demand. All fuels show increases: coal +0.8%, oil +1%, gas +1.3%.

Added to fossil emissions are those from land use, forecast at 4.1 billion tonnes: a figure slightly lower than 2024 thanks to the decline in deforestation in some key areas. Overall, total global emissions are growing much less rapidly than in the past: +0.3% per year in the last decade, compared to 1.9% in the previous decade.

A climate budget reduced to four years

The report is clear: the remaining budget to stay within 1.5 °C – 170 billion tonnes of CO₂ – is “practically exhausted”. At the rate of 2025, it will be consumed before 2030, leaving very little room for future maneuvers. At the same time, atmospheric concentration will reach 425.7 ppm, 52% higher than in pre-industrial times. Pierre Friedlingstein, who led the analysis work, summarizes it unequivocally: keeping warming below 1.5°C “is no longer plausible”.

Weakening natural wells: the most revealing data

The report delves into – also with a study in Nature – the effects of climate change on terrestrial and oceanic wells. The analysis finds that 8% of the increase in atmospheric CO₂ since 1960 is attributable to the reduction in the absorption capacity of these systems. Over the last ten years the combined well has been approximately 15% weaker than in an unaltered climate.

The end of El Niño brought terrestrial ecosystems back to previous levels, while emissions from land use decreased. In the Amazon, seasonal deforestation rates have fallen to their lowest since 2014, but the major fires of 2024 have shown how fragile the ecosystem remains in a warming climate. Meanwhile, vast tropical forests in Southeast Asia and South America have already transformed from sinks to net sources of CO₂.

Geography of emissions

The regional analysis confirms a very heterogeneous picture:

In the period 2015–2024, permanent deforestation remains high – around 4 billion tonnes per year – while reforestation and forest regrowth offset around half of it.

Ten years after Paris, the curve is not going down

Thirty-five countries today manage to reduce emissions while the economy grows, double the number of ten years ago. But these signals remain too fragile to reverse the global trajectory. “Clean” technologies are now competitive, but are implemented too slowly. Without rapid and substantial reduction, CO₂ will continue to accumulate and with it the associated risks. The goal of limiting warming to 1.5°C is not formally unattainable, but it is shrinking to a time window that now only measures a few years.

A transition that accelerates, but not enough

Despite the picture, the report signals that the energy transition is truly changing the system: in 2025 renewables will grow at a pace never recorded before and, in many countries, they will exceed new fossil installations. “Clean” electricity covers almost all new global demand, avoiding an even sharper increase in emissions. But this momentum is not enough: to return to a trajectory compatible with climate objectives it would be necessary to triple the speed of diffusion of clean technologies and gradually reduce the consumption of coal, oil and gas, which remain dominant in the global energy mix.