Human activities pushed global warming to 1.37 degrees Celsius (34.46 degrees Fahrenheit) in 2025, and the rate at which heat is building up in the Earth's system suggests high levels of future warming, scientists have warned.
The annual "indicators of global climate change" update by leading scientists across the world finds clear evidence that the world is continuing to heat, with global warming set to surpass a key threshold of 1.5 degrees Celsius (34.7 degrees Fahrenheit) in about four years.
Under 2015's global Paris Agreement, countries agreed to limit global warming to "well below" 2 degrees Celsius (35.6 degrees Fahrenheit) above pre-industrial levels and to pursue efforts to curb temperature rises to 1.5 degrees to prevent the worst droughts, heatwaves, floods, sea level rises and wildlife collapses driven by climate change.
The study, published in the journal Earth System Science Data, warns that the "carbon budget" - the amount of greenhouse gas emissions that the world can emit and still keep temperature rises to 1.5 degrees - is likely to be exhausted in just three years and the budget for 1.7 degrees Celsius (35.06 degrees Fahrenheit) will be used up in 12 years.
Emissions of climate-warming pollutants are at an all-time high, mainly from the burning of fossil fuels.
There are signs that greenhouse gas emissions growth is slowing, with factors such as the high price of oil and the shift to electric cars and renewables potentially beginning to lead to a peak and decline in emissions, researchers said.
But the findings show that global warming continues at an unprecedented rate, with the Earth heating at 0.27 degrees Celsius (32.48 degrees Fahrenheit) per decade, while 2025 was the third hottest year on record.
Professor Piers Forster, director of the Priestley Centre for Climate Futures at the University of Leeds and lead author, said: "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.
"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."
This is driving warming on land and in the oceans, which have seen a huge increase in marine heat waves, which occurred on 65 days in 2025 alone, the melting of ice and rising sea levels.
In 2025, global sea level rise reached a new record of 23-centimeter (around 9 inches) rise since 1901, with seas rising around 1.8mm (around 0.07 inches) a year, a rate that is "speeding up fast," according to Aimee Slangen, research leader at 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," she warned.
Samantha Burgess, strategic lead for climate at the EU's Copernicus Climate Change Service, said that nearly all of the warming over the past decade was driven by human activities, with the impacts on livelihoods and natural systems already being felt worldwide and set to accelerate.
She said: "There are signs that carbon dioxide emission growth is slowing and this doesn't mean that we're on track yet, but it does mean that policy, technology and societal choices are starting to bend the curve."
Burgess said it was important to have conversations to understand how to continue on the trajectory, warning "the next few years are really critical."
And she said the report, which provides annual updates on key climate indicators reported by the Intergovernmental Panel on Climate Change, is not "just a scientific scorecard."
"It's a real-time feedback system on the global climate and global climate policy," Burgess said, but she warned the global datasets, which underpinned the study, were threatened by funding changes and changes in geopolitical stability.
For example, under the Trump administration in the U.S., a network of instruments monitoring the deep ocean that has provided key climate data is being cut.
"Climate information is needed more than ever for public safety, for adaptation, for accountability and the infrastructure that provides this evidence is incredibly vulnerable at the moment," Burgess warned.
