Human-induced global warming reached 1.37°C in 2025 and is projected to surpass 1.5°C within approximately four years, according to the latest Indicators of Global Climate Change (IGCC) report, published in Earth System Science Data.
The report, produced by an international team of more than 70 scientists from 56 institutions across 17 countries, finds that the Earth’s energy imbalance – the rate at which heat is accumulating in the climate system – is at a record high, having doubled in recent decades. Global greenhouse gas emissions also reached an all-time high of 56.8 billion tonnes of CO2 equivalent in 2024, driven primarily by fossil fuel combustion.
Lead author Prof. Piers Forster, director of the Priestley Centre for Climate Futures at the University of Leeds, said, “Without human influence, the Earth’s energy imbalance should be close to zero, but it has been growing since the 1970s and is now at a record high, doubling in recent decades.”
The rate of human-induced warming stands at around 0.27°C per decade – also an all-time high – driven by record greenhouse gas levels compounded by declining sulfur dioxide emissions, which are unmasking previously hidden warming effects.
Dr Samantha Burgess, strategic lead for climate at the Copernicus Climate Change Service, said: “Our study demonstrates that nearly all of the warming over the last decade is driven by human activities. The impacts on livelihoods and ecosystems are already being felt worldwide, and will accelerate as temperatures continue to increase.”
Global sea level rise reached a new record of 23cm above 1901 levels in 2025, at a rate of around 1.8mm per year and accelerating. A newly included indicator found that 2025 alone experienced 65 days of marine heatwaves globally – part of a trend that has seen such events more than triple in frequency between 1991 and 2025.
The remaining carbon budget consistent with limiting warming to 1.5°C is estimated at 130 gigatonnes of CO2 from the start of 2026 – approximately three years’ worth of emissions at current rates.
The report also raises concerns about the future of the global datasets underpinning climate science. Dr Chris Smith of the International Institute for Applied Systems Analysis warned that more than 40 datasets used in this year’s edition are threatened by funding decisions. “Without this, future assessments will be much more difficult at a time when urgent climate action is needed,” he said.
From 2026, IGCC production is contracted by the Copernicus Climate Change Service, implemented by ECMWF on behalf of the European Commission.
In related news, ECMWF prepares release of new ORAS6 ocean reanalysis system