Warming limit of 1.5C ‘no longer plausible’ as study shows emissions at new high

Global carbon emissions from fossil fuels are set to rise 1.1% in 2025 to record highs, research has found.

New analysis finds that many countries are shifting to clean energy, but that is not enough to offset the growth in global energy demand, leading to an increase in oil, coal and gas burning which generate climate-warming emissions.

The latest annual analysis from the global carbon budget project does find that projected emissions from changes to how land is used, such as deforestation, are down from 2024 levels to 4.1 billion tonnes in 2025.

That means that overall carbon dioxide emissions for this year are projected to be slightly lower than last year.

But the remaining global carbon budget – the amount of emissions that can be put into the atmosphere over time without pushing up temperatures beyond a certain amount – for the agreed global warming limit of 1.5C above pre-industrial levels is “nearly exhausted”, the study warns.

It will be used up in four years at current levels of pollution.

The report estimates the world is putting out 38.1 billion tonnes of carbon dioxide from fossil fuels, including cement production, in 2025, up 1.1% on 2024’s levels, and a new record high.

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

The report finds that the end of the 2023/2024 El Nino weather pattern – a phenomenon in the tropical Pacific that causes extra heat and drought in many regions – this year means that the ability of “sinks” such as forests to absorb carbon have returned to pre-El Nino levels.

The cut in emissions from land use change has largely been down to the end of the El Nino, and the recovery of these carbon “sinks”, the scientists said.

But the study, published alongside a new paper in the journal Nature, warns that the ability of landscapes and oceans to absorb carbon is declining as the planet warms.

Some 8% of the rise in the amount of carbon dioxide in the atmosphere since 1960 is because of climate change weakening the land and ocean “sinks” and making them less able to absorb carbon, the scientists warn.

Professor Friedlingstein said: “The remaining carbon budget for 1.5C, 170 billion tonnes of carbon dioxide, will be gone before 2030 at current emission rates.

“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.”

The warning comes as countries meet for the latest round of UN climate talks, Cop30, in Belem, Brazil, which are taking place against a backdrop of retreat from action by nations including the US – even as global temperatures continue to climb and extreme storms, droughts and heatwaves worsen.

Among the major emitters, the report finds emissions are expected to grow in the US and EU, reversing long-term declines, and also in China and India – though in those two countries, pollution is rising more slowly than in recent years with strong growth in renewables.

Emissions from permanent deforestation “remain high” at around four billion tonnes per year on average in the past decade, with carbon removed through reforestation, new forests, and regrowth offsetting about half of the deforestation emissions.

Total carbon dioxide emissions, adding together fossil fuel pollution and land use change, have grown more slowly in the past decade at 0.3% a year, compared with 1.9% a year in the previous decade.

And fossil fuel-linked carbon dioxide emissions decreased in 35 countries with growing economies, a figure that has nearly doubled since the previous decade, showing that pollution can be cut.

Professor Corinne Le Quere, from the University of East Anglia, said: “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.”

But she said: “Progress is still much too fragile to translate into the sustained decreases in global emissions needed to tackle climate change.”

Glen Peters, senior researcher at the Cicero Centre for International Climate Research, added that in the 10 years since the world agreed the Paris climate treaty to curb rising temperatures, emissions had continued “their relentless rise”.

“It is clear countries need to lift their game,” he said.

“We now have strong evidence that clean technologies help reduce emissions while being cost effective compared to fossil alternatives.”

Reaching global “net zero” carbon dioxide emissions – where no more of the gas is being put out than absorbed by the Earth’s systems – by 2050, to halt rising temperatures, would require cuts of 4% each year, comparable with what happened when the world shut down in the face of the Covid pandemic.

But that would still lead to far more emissions than the estimated budget for keeping temperatures to 1.5C but within the remaining budget for keeping warming to 1.7C above pre-industrial levels, the study found.