Human activities pushed global warming to 1.37°C above pre-industrial levels in 2025. Scientists have warned that the world will probably exceed the critical 1.5°C threshold within four years if emissions continue at current levels.
The findings come from the latest Indicators of Global Climate Change (IGCC) report, released during the Bonn climate talks and published in the journal Earth System Science Data.
Compiled by more than 70 scientists from 56 institutions across 17 countries, the assessment paints a picture of a climate system changing at an accelerating pace.
The study finds that global greenhouse gas emissions remain at record levels, greenhouse gas concentrations continue to rise in the atmosphere and the Earth is accumulating heat faster than at any point in the modern record.
A key concern is the Earth’s energy imbalance — the difference between the amount of energy entering the planet from the sun and the amount escaping back into space.
“A key indicator is the Earth’s energy imbalance, which measures how fast heat is accumulating in the climate system and provides a crucial measure of the pace of climate change,” said the study's lead author, professor Piers Forster, the director of the Priestley Centre for Climate Futures at the University of Leeds.
“Without human influence, it should be close to zero but it has been growing since the 1970s and is now at a record high, doubling in recent decades.”
According to the report, the growing energy imbalance is driving rising temperatures across the oceans, land and the Earth’s frozen regions, contributing to ocean warming, ice loss, thawing permafrost and accelerating sea-level rise.
The study found that global greenhouse gas emissions reached a record 56.8 billion tonnes of carbon dioxide equivalent in 2024, driven largely by the continued burning of coal, oil and gas, alongside emissions from agriculture, deforestation and industry.
Atmospheric concentrations of the three main greenhouse gases — carbon dioxide, methane and nitrous oxide — also reached record levels in 2025. Since 2019, concentrations of carbon dioxide and methane have each risen by 3.8%, while nitrous oxide concentrations have increased by 2.2%.
Scientists found that nearly all the warming experienced over the past decade can be attributed to human activities. Human-induced warming is increasing at about 0.27°C per decade, the fastest rate yet recorded.
“The impacts on livelihoods and ecosystems are already being felt worldwide and will accelerate as temperatures continue to increase,” said Dr Samantha Burgess, the strategic lead for climate at the Copernicus Climate Change Service.
The report also found growing evidence of climate change in extreme weather and temperature indicators. Average annual maximum temperatures over land during the past decade reached 1.92°C above pre-industrial levels, nearly half a degree warmer than during the previous decade.
Marine heatwaves are becoming increasingly common. The number of marine heatwave days has more than tripled globally since 1991, with 65 marine heatwave days recorded worldwide last year alone. Scientists warn these events can damage marine ecosystems, threaten fisheries and food production and intensify weather extremes on land.
Sea levels also continue to climb. The report found that global mean sea level reached a record 23cm above 1901 levels in 2025 and is rising at around 1.8mm a year, driven by warming oceans and melting land-based ice.
The rate was speeding up, said Dr Aimée Slangen of the Royal Netherlands Institute for Sea Research. “This might sound small but even this level of change is increasing coastal flooding in low-lying areas around the world, harming livelihoods and ecosystems.”
The remaining carbon budget — the amount of carbon dioxide humanity can emit while retaining a reasonable chance of limiting warming to 1.5°C — has shrunk to an estimated 130 billion tonnes of CO₂ from the start of 2026.
At current emission rates, the budget would be exhausted in about three years.
The authors say the findings underscore how rapidly the climate is changing and highlight the urgent need to accelerate global decarbonisation efforts during this decade. They also warn that many of the observational datasets used to track these changes are increasingly vulnerable to funding cuts.
“This year’s edition of IGCC has involved over 40 global datasets, many of which are now threatened by funding decisions,” said Dr Chris Smith of the International Institute for Applied Systems Analysis.
“We need concerted international action and coordination to ensure the continuity of observations of the climate. Without this, future assessments will be much more difficult at a time when urgent climate action is needed.”