Scientists warn the 1.5 ° C -earth carbon budget has almost disappeared

At current emission rates, the world has just over three years before exceeding the carbon budget necessary to limit warming to 1.5 ° C.

The rise of the seas, the warmer oceans and the record global temperatures underline how fast the climate crisis is accelerating and why the urgent action is essential.

The carbon budget is close to the critical threshold

The latest indicators of the global climate change report warn that the carbon budget remaining in the world to limit warming to 1.5 ° C is estimated at only 130 billion tonnes of CO₂ (from the beginning of 2025). At today’s emission rate, this budget will be fully used in just over three years, and the thresholds of 1.6 ° C or 1.7 ° C could be crossed in less than nine years.

Professor Piers Forster, director of the Priestley Center for Climate Futures at the University of Leeds and the main author of the study, explained: “Our third annual edition of the indicators of global climate change shows that the levels of warming and the warming rates are unprecedented. Underline how climate policies and the pace of climate action do not follow what is necessary to treat the impacts in constant increase. »»

Ten key indicators of the updated climate

This year’s analysis has involved more than 60 international scientists and has expanded its scope to include an elevation of sea level and global land precipitation, bringing the total to 10 critical indicators.^[1] Data provide political decision -makers an up -to -date and complete view of the planet’s climate system.

For 2024, researchers estimate that overall surface temperatures were 1.52 ° C higher than pre -industrial levels, with 1.36 ° C of this warming directly linked to human activities.^[2] The study attributes this sharp increase to greenhouse gas emissions remaining at record peaks in recent years, resulting in rapid and unprecedented warming.

Alarming temperatures and the Paris Agreement

According to the study, the high temperatures of 2024 are “non -exceptional alarming”, given the level of climate change caused by humans. This human influence is at a record level and, combined with a natural variability of the climate system (which varies temperatures naturally from one year to the next), has grown the increase in world average temperature at record levels.

Although the 1,5 ° C damage to the global temperature increase in a single year does not mean that there has been a violation of the Paris Historic Agreement – for this, the average global temperatures should exceed 1.5 ° C over several decades – these results reaffirm how far and rapid emissions are headed in the wrong direction. And the impacts will only worsen when CO2 emissions from fossil fuels and deforestation reach the net zero.

Decade of entirely induced warming

During the analysis of the longer-term temperature change, the best estimates show that between the 2015-2024 average global temperatures were 1.24 ° C higher than at the pre-industrial era, with 1.22 ° C caused by human activities, which means that, essentially, our best estimate is that all the warming that we have seen in the last decade was induced by humans.

Human activities have led to the equivalent of around 53 billion tonnes of CO2 (GT CO2E) released each year in the atmosphere in the last decade, mainly due to the increase in emissions for fossil fuel and deforestation. In 2024, emissions from international aviation – the sector with the most steep drop in emissions during the pandemic – also returned to pre -pale levels.

GHG emissions have also led to higher levels of greenhouse gas accumulating in the atmosphere. Combined with a drop in sulfur dioxide emissions (SO2) leading to planet cooling aerosols, the result is that the planet continues to warm up. The damage caused by aerosols with human health prevail from far away on minimum cooling “gains”, and there are other short -term GHGs that may and should be addressed alongside CO2, such as methane (CH4), which could provide short -term cooling compensation for the drop in aerosols.

The energy imbalance of the land doubles the heating rate

Human activities have also affected the energy balance of the earth. The excess heat accumulates in the terrestrial system at an acceleration rate leads to changes in each component of the climate system. The global heating rate observed between 2012 and 2024 has been doubled compared to the levels observed in the 1970s and 1980s, resulting in harmful changes in vital components, including elevation of sea level, ocean warming, ice loss and pergilelisol thaw.

Dr. Karina von Schuckmann, principal advisor, Ocean Science for Policy at Mercator Ocean International, said: “The ocean stored approximately 91% of this excess heat driven by greenhouse gas emissions, which leads to warming of the ocean.

Sea level increases to accelerate the pace

Between 2019 and 2024, the world’s average sea level also increased by around 26 mm, more than double the long -term rate of 1.8 mm per year since the beginning of the 20th century.

Dr. Aimée Slangen, research manager at Nioz Royal Netherlands Institute for Sea Research, said: “Since 1900, the average world level of the sea has increased by around 228 mm. This apparently small number has a disproportionate impact on the low coastal areas, which makes storms more harmful and causes coastal erosion, the threat of the reaction of the acts of the sea. Climate change is relatively slow, which means that we have already locked additional increases in the years and decades to come. »»

Fast closing window at 1.5 ° C

The latest IPCC assessment of the climate system, published in 2021, underlined how climate change led to generalized unfavorable effects on nature and people, with rapid and deep reductions of GHG emissions necessary to limit warming to 1.5 ° C.

Prof. Jeri Rogelj, research director at the Grantham Institute and Climate Science & Policy Professor at the Center for Environmental Policy at Imperial College London said: “The window to stay at less than 1.5 ° C closes quickly. Climate warming already affects the lives of billions of people worldwide. Each small increase in warming issues, leading to more frequent and more intense weather conditions. Emissions during the next decade will quickly determine and when 1.5 ° C of warming is reached.

Other key results:

• Human warming increased at a speed of approximately 0.27 ° C / decade (2015-2024).
• The last decade (2015-2024) was 0.31 ° C warmer than the previous decade (2005-2014). These changes, although somewhat amplified by the years exceptionally hot in 2023 and 2024, are largely consistent with warming rates in recent decades.
• Rapid warming in recent decades has resulted in extreme temperatures records on earth, with average maximum temperatures reaching 1.9 ° C during the 2015-2024 decade and increasing at a significantly faster pace than the global surface global temperature.

Notes

1. Complete list of indicators:
   • Greenhouse gas emissions
   • Greenhouse gas concentrations and short -term climatic climatic requirements
   • Effective radiative forcing;
   • Earth energy imbalance
   • Observations of the overall surface temperature change
   • Temperature change induced by humans
   • Carbon budget remaining for relevant temperature thresholds
   • Maximum land surface temperatures
   • Global land precipitation
   • World level elevation
2. The study calculated 1.52 ° C as the best estimate of the overall surface temperature observed in 2024. This number differs from 1.55 ° C given by the state of the global meteorological organization (WMO) of the global climate ratio 2024. This is due to slightly distinct selections of the sets of available data included. The number has varied by similar amounts in recent years. Future work will aim to harmonize approaches.

Reference: “Indicators of global climate change 2024: Annual update of key indicators of the state of the climate system and human influence” by Piers M. Forster, Chris Smith, Tristram Walsh, William F. Lamb, Robin Lamboll, Christophe Cassou, Mathias Hauser Szopa, Blair Trewin, Jeongeun Yun, Nathan P. Gillett, Stuart Jenkins, H. Damon Matthews, Krishnan Raghavan, Aurélien Ribes, Jeri Rogelj, Debbie Rosen, Xuebin Zhang, Myles Allen, Lara Aleluia Reis, Robbie M. and Richard, Richard A. Borger, Jiddua Reis, Robbie M. and Richard, Richard A. Borger, Jiddua Reis Robbie M. and Richard, Richard. A. Broersma, Samantha N. Burgess, Lijing Cheng, Pierre Friedlingtein, Catia M. Domingues, Marco Gambarini, Thomas Gasser, Johannes Gütschow, Masayoshi Ishii, Christopher Kadow, John Kennedy, Rachel E. Killick, Paul B. Krummel, Aurélien Line Jens Mühle, Naik, Glen P. Peters, Anna Pirani, Julia Pongratz, Jan C. Minx, Matthew Rigby, Robert Rohde, Abhishek Savita, Sonia I. Seneviratne, Peter Thorne, Christopher Wells, Luke M. Western, Guid R. Van Der Werf, Susan E. Wijffel Masson-Delmotte and Panmao Zhai, 19 June 2025, Earthly system scientific data.
Two: 10.5194 / ESSD-17-2641-2025

Never miss a breakthrough: join the Scitechdaily newsletter.