Global climate indicators show faster human-driven warming
The 2025 IGCC update says human-driven warming, emissions, sea levels and marine heatwaves are rising as the world nears the 1.5°C threshold.
- Human-induced warming reached 1.37°C above pre-industrial levels in 2025, with the rate of warming holding at a record high of 0.27°C per decade.
- The warming is driven by record-high greenhouse gas emissions from human activities, which have pushed atmospheric concentrations of carbon dioxide, methane, and nitrous oxide to new highs.
- Multiple indicators show accelerating change, including a rapid increase in the rate of sea-level rise, a tripling in the frequency of marine heatwaves, and a doubling of Earth's energy imbalance in recent decades.
- At the current pace, the remaining carbon budget for limiting warming to 1.5°C will be exhausted in approximately three years, with the world projected to cross this threshold around 2030.
The fourth edition of the Indicators of Global Climate Change (IGCC) report for 2025, prepared by an international team of more than 70 scientists, sets out an overview of a climate crisis that is worsening rapidly and continuously, attributing the changes to human activity.
In 2025, human-induced warming reached 1.37°C above pre-industrial levels.
The figure is consistent with actual measurements of global surface temperature, which found 2025 was the third-hottest year on record, with natural variability playing only a small role.
During 2016–2025, the rate of warming caused by human activity remained at a record high of 0.27°C per decade.
Scientists warned that, if this trend continues, the world will cross the Paris Agreement’s key 1.5°C threshold around 2030, or in about four years, earlier than many had expected.
The report said global greenhouse gas emissions reached a record high of 56.8 billion tonnes of carbon dioxide equivalent in 2024, driven mainly by fossil-fuel combustion.
Although the rate of carbon dioxide emissions has begun to slow slightly, the total volume of gases released continues to rise at a worrying pace.
The concentrations of the three main greenhouse gases in the atmosphere, carbon dioxide, methane and nitrous oxide, all set new records in 2025. Carbon dioxide in particular rose to 425.6 parts per million (ppm), up 3.8% from 2019, showing that these gases are trapping more heat in the atmosphere.
Samantha Burgess of the Copernicus Climate Change Service (C3S) said global warming over the past decade was almost entirely caused by human activity and was affecting ways of life and ecosystems around the world.
She said the situation would worsen if temperatures continued to rise without serious restraint.
At the same time, another factor accelerating warming is the fall in sulphur dioxide caused by air-pollution control measures.
This has had the side effect of weakening the heat-shielding effect of aerosols and pushing Earth’s energy imbalance, or EEI, to a new record, with the measure more than doubling over the past few decades.
EEI is a condition in which the Earth receives more energy from the sun than it radiates back into space.
Since 1901, global mean sea level (GMSL) has risen by 23 centimetres, while in the latest decade it has accelerated rapidly to 3.67 millimetres per year.
Aimée Slangen, a scientist and research leader at the Royal Netherlands Institute for Sea Research, said the figure may appear small, but it has made coastal flooding more severe in low-lying areas, threatening the well-being of people and coastal ecosystems worldwide.
The report also introduced “marine heatwaves” as a new indicator because they have become more than three times more frequent compared with 1991.
In 2025 alone, the world experienced 65 days of marine heatwaves, damaging marine ecosystems, threatening food security, and potentially making extreme weather on land more severe.
Meanwhile, the “average maximum land temperature” during 2016–2025 rose by 1.92°C compared with pre-industrial levels, nearly 0.5°C higher than in the previous decade.
Extreme heat is also moving towards levels that are seriously dangerous to human health and livelihoods.
The remaining carbon budget (RCB) for limiting warming to no more than 1.5°C stood at just 130 billion tonnes from the start of 2026.
If carbon dioxide emissions continue at current levels, the available RCB will be exhausted in about three years, signalling that the Paris Agreement target can no longer be kept.
Chris Smith, a scientist and senior research scholar at the International Institute for Applied Systems Analysis (IIASA), expressed deep concern over a possible lack of funding support for global climate observation networks and satellites, especially because of political decisions in some countries.
He said the loss of accurate and continuous data would make it harder to assess the situation and make policy decisions to respond to the future climate crisis, particularly at a time when the world most urgently needs action.
The report stressed that renewable energy and the transition to electrification alone are not enough.
Governments worldwide must step up efforts to cut carbon emissions during the 2020s, because failing to do so would bring severe and potentially irreversible impacts for future generations.
