Indicators of Global Climate Change 2025: annual update of key indicators of the state of the climate system and human influence

@article{forster2026indicators,
  title = {{Indicators of Global Climate Change 2025: annual update of key indicators of the state of the climate system and human influence}},
  author = {Piers M. de F. Forster and Tristram Walsh and Chris Smith and William F. Lamb and Robin Lamboll and Christophe Cassou and Mathias Hauser and Zeke Hausfather and June‐Yi Lee and Matthew D. Palmer and Karina von Schuckmann and Aimée B. A. Slangen and Sophie Szopa and Blair C. Trewin and Jeongeun Yun and Nathan P. Gillett and Stuart Jenkins and H. Damon Matthews and Krishnan Raghavan and Aurélien Ribes and Joeri Rogelj and Debbie Rosen and Xuebin Zhang and Myles R. Allen and Robbie M. Andrew and Chris Atkinson and Richard Betts and Antonio Bombelli and Samantha Burgess and Lijing Cheng and Helen E. Claxton and Pierre Friedlingstein and Thomas Lukas Frölicher and Catia M. Domingues and Thomas Gasser and Catherine H. Gregory and Rachel Hoesly and Daniel Huppmann and Masayoshi Ishii and Christopher Kadow and Alexia Karwat and John Kennedy and Rachel Killick and Mahesh Kovilakam and Paul B. Krummel and Xin Lan and Jean-François Lamarque and Aurélien Liné and Belén Martín-Míguez and Didier P. Monselesan and Colin Morice and Jens Mühle and Pino Mussak and Glen P. Peters and Anna Pirani and Julia Pongratz and Matthew Rigby and Robert A. Rohde and Abhishek Savita and Sonia Isabelle Seneviratne},
  journal = {Earth system science data},
  year = {2026},
  month = jun,
  doi = {10.5194/essd-18-3889-2026},
  url = {https://doi.org/10.5194/essd-18-3889-2026},
  note = {CC BY},
}

TY  - JOUR
TI  - Indicators of Global Climate Change 2025: annual update of key indicators of the state of the climate system and human influence
AU  - Piers M. de F. Forster
AU  - Tristram Walsh
AU  - Chris Smith
AU  - William F. Lamb
AU  - Robin Lamboll
AU  - Christophe Cassou
AU  - Mathias Hauser
AU  - Zeke Hausfather
AU  - June‐Yi Lee
AU  - Matthew D. Palmer
AU  - Karina von Schuckmann
AU  - Aimée B. A. Slangen
AU  - Sophie Szopa
AU  - Blair C. Trewin
AU  - Jeongeun Yun
AU  - Nathan P. Gillett
AU  - Stuart Jenkins
AU  - H. Damon Matthews
AU  - Krishnan Raghavan
AU  - Aurélien Ribes
AU  - Joeri Rogelj
AU  - Debbie Rosen
AU  - Xuebin Zhang
AU  - Myles R. Allen
AU  - Robbie M. Andrew
AU  - Chris Atkinson
AU  - Richard Betts
AU  - Antonio Bombelli
AU  - Samantha Burgess
AU  - Lijing Cheng
AU  - Helen E. Claxton
AU  - Pierre Friedlingstein
AU  - Thomas Lukas Frölicher
AU  - Catia M. Domingues
AU  - Thomas Gasser
AU  - Catherine H. Gregory
AU  - Rachel Hoesly
AU  - Daniel Huppmann
AU  - Masayoshi Ishii
AU  - Christopher Kadow
AU  - Alexia Karwat
AU  - John Kennedy
AU  - Rachel Killick
AU  - Mahesh Kovilakam
AU  - Paul B. Krummel
AU  - Xin Lan
AU  - Jean-François Lamarque
AU  - Aurélien Liné
AU  - Belén Martín-Míguez
AU  - Didier P. Monselesan
AU  - Colin Morice
AU  - Jens Mühle
AU  - Pino Mussak
AU  - Glen P. Peters
AU  - Anna Pirani
AU  - Julia Pongratz
AU  - Matthew Rigby
AU  - Robert A. Rohde
AU  - Abhishek Savita
AU  - Sonia Isabelle Seneviratne
PY  - 2026
DA  - 2026/06/05
JO  - Earth system science data
DO  - 10.5194/essd-18-3889-2026
UR  - https://doi.org/10.5194/essd-18-3889-2026
AB  - In a rapidly changing climate, evidence-based decision-making benefits from up-to-date and timely information. We track twelve key sets of indicators of the state of the climate system, closely following Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment report (AR6) methods, to produce our fourth annual publication. One of the indicators, the Earth's energy imbalance (EEI) provides a crucial integrative measure of the pace of climate change – this has more than doubled since the 1976–1995 period. A newly updated indicator of temperature extremes, the number of days experiencing marine heatwaves, has more than tripled between 1991 and 2025. For the 2016–2025 decade average, observed warming relative to 1850–1900 was 1.26 [1.13 to 1.36] °C, of which 1.24 [1.0 to 1.5] °C was human-induced. Human-induced warming reached 1.37 °C relative to 1850-1900 in the year 2025, increasing at a rate of 0.27 [0.2–0.4] °C per decade over 2016–2025. This high rate of warming, which matches the all-time high seen last year in the instrumental record, was caused by a combination of greenhouse gas emissions being at an all-time high of 54.6 ± 5.5 GtCO2e per year over the last decade (2015–2024), as well as reductions in the strength of aerosol cooling. Despite this, there is evidence that CO2 emission growth is slowing. The continuation of these annual updates could track decreases or increases in the rate of human influence and climatic changes presented here, reflecting the outcomes of societal choices during the critical 2020s decade. In total, we employ analysis from over 40 global datasets (https://doi.org/10.5281/ZENODO.7883757 Smith et al., 2026a) These data are threatened by geopolitical and public funding decisions that are cutting support for key satellite and in-situ observing programs critical for the monitoring of the atmosphere, ocean, cryosphere and land surface, including long-term data preservation and provision that is key to understanding our changing climate for today and for future generations. Overall, the Global Climate Observing System (GCOS) framework, which supports much of our international capability, is under threat. Our ability to monitor effectively many of the indicators presented herein is not guaranteed without concerted international action to ensure the continuity of observation programs and coordination mechanisms, including the GCOS program, that enable their effective integration and use.
SN  - 1866-3508
SN  - 1866-3516
ER  -