Data
Human-induced warming since 1850–1900, each year, annual-mean definition (IGCC 2025)
How much of the global surface warming in each year since 1850 was caused by human activity, relative to the 1850–1900 average, with the likely range, by the annual-mean definition. Indicators of Global Climate Change combines three attribution methods; this series applies its stated assessment rule to each year's annual-mean estimate. IGCC's headline figure for a single year uses the trend-based definition of the IPCC 1.5 °C report instead (published separately as human-induced warming in 2025) and can differ by a few hundredths of a degree.
Latest value
1.38°C
Global mean, 2025. Version IGCC-2025a.
Human-induced warming since 1850–1900, each year, annual-mean definition (IGCC 2025) (degrees Celsius)
Human-induced warming since 1850–1900, each year, annual-mean definition (IGCC 2025) (degrees Celsius)
Show as a table
| Period | Value (°C) | Range | Status |
|---|---|---|---|
| 1850 | −0.03 | −0.20 to 0.10 | final |
| 1851 | −0.04 | −0.20 to 0.10 | final |
| 1852 | −0.04 | −0.20 to 0.10 | final |
| 1853 | −0.03 | −0.20 to 0.10 | final |
| 1854 | −0.01 | −0.20 to 0.20 | final |
| 1855 | −0.02 | −0.30 to 0.20 | final |
| 1856 | −0.03 | −0.20 to 0.10 | final |
| 1857 | −0.02 | −0.20 to 0.10 | final |
| 1858 | −0.01 | −0.20 to 0.20 | final |
| 1859 | 0.01 | −0.10 to 0.20 | final |
| 1860 | −0.01 | −0.20 to 0.10 | final |
| 1861 | −0.02 | −0.20 to 0.10 | final |
| 1862 | −0.02 | −0.30 to 0.20 | final |
| 1863 | −0.01 | −0.30 to 0.20 | final |
| 1864 | −0.02 | −0.20 to 0.10 | final |
| 1865 | −0.03 | −0.20 to 0.10 | final |
| 1866 | −0.02 | −0.20 to 0.10 | final |
| 1867 | 0.00 | −0.20 to 0.20 | final |
| 1868 | −0.01 | −0.20 to 0.10 | final |
| 1869 | −0.01 | −0.30 to 0.20 | final |
| 1870 | −0.01 | −0.20 to 0.20 | final |
| 1871 | −0.01 | −0.20 to 0.10 | final |
| 1872 | −0.01 | −0.10 to 0.10 | final |
| 1873 | −0.01 | −0.20 to 0.10 | final |
| 1874 | 0.00 | −0.10 to 0.10 | final |
| 1875 | 0.00 | −0.20 to 0.20 | final |
| 1876 | 0.00 | −0.20 to 0.20 | final |
| 1877 | −0.01 | −0.20 to 0.10 | final |
| 1878 | 0.00 | −0.10 to 0.10 | final |
| 1879 | 0.03 | −0.10 to 0.20 | final |
| 1880 | 0.02 | −0.10 to 0.20 | final |
| 1881 | 0.00 | −0.20 to 0.20 | final |
| 1882 | 0.00 | −0.10 to 0.10 | final |
| 1883 | 0.01 | −0.20 to 0.20 | final |
| 1884 | 0.02 | −0.10 to 0.20 | final |
| 1885 | 0.01 | −0.20 to 0.20 | final |
| 1886 | 0.01 | −0.20 to 0.20 | final |
| 1887 | 0.00 | −0.20 to 0.10 | final |
| 1888 | 0.01 | −0.10 to 0.20 | final |
| 1889 | 0.02 | −0.10 to 0.20 | final |
| 1890 | 0.01 | −0.10 to 0.20 | final |
| 1891 | 0.00 | −0.10 to 0.10 | final |
| 1892 | 0.01 | −0.20 to 0.20 | final |
| 1893 | 0.02 | −0.20 to 0.30 | final |
| 1894 | 0.04 | −0.10 to 0.20 | final |
| 1895 | 0.03 | −0.10 to 0.20 | final |
| 1896 | 0.02 | −0.10 to 0.20 | final |
| 1897 | 0.03 | −0.10 to 0.20 | final |
| 1898 | 0.03 | −0.10 to 0.20 | final |
| 1899 | 0.04 | −0.10 to 0.20 | final |
| 1900 | 0.04 | −0.10 to 0.20 | final |
| 1901 | 0.04 | −0.10 to 0.20 | final |
| 1902 | 0.03 | −0.10 to 0.20 | final |
| 1903 | 0.02 | −0.20 to 0.20 | final |
| 1904 | 0.02 | −0.30 to 0.30 | final |
| 1905 | 0.03 | −0.20 to 0.30 | final |
| 1906 | 0.01 | −0.20 to 0.10 | final |
| 1907 | 0.03 | −0.20 to 0.20 | final |
| 1908 | 0.03 | −0.10 to 0.20 | final |
| 1909 | 0.03 | −0.20 to 0.20 | final |
| 1910 | 0.04 | −0.10 to 0.30 | final |
| 1911 | 0.03 | −0.20 to 0.20 | final |
| 1912 | 0.05 | −0.20 to 0.40 | final |
| 1913 | 0.05 | −0.20 to 0.40 | final |
| 1914 | 0.03 | −0.20 to 0.20 | final |
| 1915 | 0.03 | −0.20 to 0.20 | final |
| 1916 | 0.05 | −0.20 to 0.30 | final |
| 1917 | 0.08 | −0.10 to 0.40 | final |
| 1918 | 0.07 | −0.20 to 0.40 | final |
| 1919 | 0.06 | −0.20 to 0.30 | final |
| 1920 | 0.07 | −0.10 to 0.30 | final |
| 1921 | 0.08 | −0.10 to 0.30 | final |
| 1922 | 0.09 | −0.10 to 0.30 | final |
| 1923 | 0.09 | −0.10 to 0.30 | final |
| 1924 | 0.08 | −0.10 to 0.30 | final |
| 1925 | 0.08 | −0.10 to 0.30 | final |
| 1926 | 0.09 | −0.10 to 0.30 | final |
| 1927 | 0.10 | −0.10 to 0.30 | final |
| 1928 | 0.11 | −0.10 to 0.30 | final |
| 1929 | 0.12 | −0.10 to 0.40 | final |
| 1930 | 0.11 | −0.10 to 0.40 | final |
| 1931 | 0.10 | −0.10 to 0.30 | final |
| 1932 | 0.11 | −0.10 to 0.30 | final |
| 1933 | 0.12 | 0.00 to 0.40 | final |
| 1934 | 0.13 | 0.00 to 0.30 | final |
| 1935 | 0.12 | 0.00 to 0.30 | final |
| 1936 | 0.13 | 0.00 to 0.30 | final |
| 1937 | 0.14 | 0.00 to 0.40 | final |
| 1938 | 0.14 | −0.10 to 0.50 | final |
| 1939 | 0.12 | 0.00 to 0.30 | final |
| 1940 | 0.12 | −0.10 to 0.30 | final |
| 1941 | 0.12 | −0.10 to 0.30 | final |
| 1942 | 0.12 | −0.10 to 0.30 | final |
| 1943 | 0.15 | −0.10 to 0.50 | final |
| 1944 | 0.15 | −0.10 to 0.40 | final |
| 1945 | 0.14 | −0.10 to 0.40 | final |
| 1946 | 0.14 | −0.10 to 0.30 | final |
| 1947 | 0.15 | 0.00 to 0.30 | final |
| 1948 | 0.19 | 0.00 to 0.50 | final |
| 1949 | 0.18 | 0.00 to 0.50 | final |
| 1950 | 0.17 | −0.10 to 0.50 | final |
| 1951 | 0.16 | −0.10 to 0.40 | final |
| 1952 | 0.16 | 0.00 to 0.30 | final |
| 1953 | 0.15 | −0.10 to 0.30 | final |
| 1954 | 0.17 | −0.10 to 0.40 | final |
| 1955 | 0.18 | 0.00 to 0.40 | final |
| 1956 | 0.17 | −0.10 to 0.40 | final |
| 1957 | 0.18 | 0.00 to 0.40 | final |
| 1958 | 0.19 | 0.00 to 0.40 | final |
| 1959 | 0.19 | 0.00 to 0.40 | final |
| 1960 | 0.19 | 0.00 to 0.40 | final |
| 1961 | 0.18 | 0.00 to 0.40 | final |
| 1962 | 0.19 | −0.10 to 0.40 | final |
| 1963 | 0.21 | 0.00 to 0.50 | final |
| 1964 | 0.20 | 0.00 to 0.40 | final |
| 1965 | 0.19 | 0.00 to 0.40 | final |
| 1966 | 0.20 | 0.00 to 0.40 | final |
| 1967 | 0.21 | 0.00 to 0.40 | final |
| 1968 | 0.22 | 0.00 to 0.40 | final |
| 1969 | 0.23 | 0.00 to 0.50 | final |
| 1970 | 0.23 | 0.00 to 0.50 | final |
| 1971 | 0.25 | 0.00 to 0.40 | final |
| 1972 | 0.24 | 0.00 to 0.50 | final |
| 1973 | 0.25 | 0.10 to 0.50 | final |
| 1974 | 0.27 | 0.00 to 0.50 | final |
| 1975 | 0.29 | 0.10 to 0.50 | final |
| 1976 | 0.30 | 0.00 to 0.60 | final |
| 1977 | 0.31 | 0.10 to 0.50 | final |
| 1978 | 0.33 | 0.00 to 0.60 | final |
| 1979 | 0.32 | 0.00 to 0.50 | final |
| 1980 | 0.34 | 0.10 to 0.50 | final |
| 1981 | 0.36 | 0.10 to 0.60 | final |
| 1982 | 0.41 | 0.20 to 0.70 | final |
| 1983 | 0.42 | 0.20 to 0.60 | final |
| 1984 | 0.42 | 0.10 to 0.70 | final |
| 1985 | 0.44 | 0.20 to 0.60 | final |
| 1986 | 0.45 | 0.20 to 0.70 | final |
| 1987 | 0.47 | 0.20 to 0.80 | final |
| 1988 | 0.51 | 0.30 to 0.80 | final |
| 1989 | 0.53 | 0.30 to 0.80 | final |
| 1990 | 0.53 | 0.40 to 0.70 | final |
| 1991 | 0.55 | 0.40 to 0.70 | final |
| 1992 | 0.58 | 0.40 to 0.80 | final |
| 1993 | 0.60 | 0.40 to 0.80 | final |
| 1994 | 0.61 | 0.40 to 0.80 | final |
| 1995 | 0.63 | 0.30 to 0.90 | final |
| 1996 | 0.65 | 0.40 to 0.90 | final |
| 1997 | 0.68 | 0.50 to 0.90 | final |
| 1998 | 0.69 | 0.50 to 0.90 | final |
| 1999 | 0.73 | 0.50 to 0.90 | final |
| 2000 | 0.74 | 0.50 to 0.90 | final |
| 2001 | 0.76 | 0.50 to 1.00 | final |
| 2002 | 0.79 | 0.60 to 1.10 | final |
| 2003 | 0.82 | 0.60 to 1.10 | final |
| 2004 | 0.83 | 0.60 to 1.10 | final |
| 2005 | 0.84 | 0.70 to 1.10 | final |
| 2006 | 0.87 | 0.70 to 1.10 | final |
| 2007 | 0.89 | 0.70 to 1.20 | final |
| 2008 | 0.92 | 0.70 to 1.30 | final |
| 2009 | 0.94 | 0.70 to 1.30 | final |
| 2010 | 0.94 | 0.80 to 1.10 | final |
| 2011 | 0.99 | 0.80 to 1.30 | final |
| 2012 | 1.02 | 0.80 to 1.30 | final |
| 2013 | 1.04 | 0.80 to 1.40 | final |
| 2014 | 1.04 | 0.80 to 1.30 | final |
| 2015 | 1.06 | 0.90 to 1.20 | final |
| 2016 | 1.09 | 0.90 to 1.30 | final |
| 2017 | 1.14 | 0.90 to 1.40 | final |
| 2018 | 1.18 | 1.00 to 1.50 | final |
| 2019 | 1.19 | 1.00 to 1.40 | final |
| 2020 | 1.22 | 0.90 to 1.60 | final |
| 2021 | 1.26 | 1.00 to 1.60 | final |
| 2022 | 1.28 | 1.10 to 1.50 | final |
| 2023 | 1.31 | 1.10 to 1.60 | final |
| 2024 | 1.36 | 1.10 to 1.80 | final |
| 2025 | 1.38 | 1.10 to 1.70 | final |
Calculated by Environment Dashboard from Indicators of Global Climate Change 2025: Forster et al. (2026), Earth Syst. Sci. Data 18, 3889–3933, doi:10.5194/essd-18-3889-2026; data: Smith et al. (2026), version IGCC-2025a, doi:10.5281/zenodo.21494229. CC BY 4.0. Changes: best estimate and likely range for each year computed from the three methods' annual percentiles with IGCC's stated multi-method assessment rule. CC BY 4.0.
Where it comes from
- Producer
- Indicators of Global Climate Change (IGCC) consortium, led by the University of Leeds · Indicators of Global Climate Change 2025
- Version
- IGCC-2025a
- Fetched
- 2026-10-04 (automatically), 1,495,354 bytes
- Fingerprint
- sha256 04658ff91053808aced03f65dc977311668aec1610ec83bec72fff303dcbcbcd
- Copies
- No Wayback copy recorded yet.Our copy of the exact file
- Cite the producer
- Forster, P. M., Walsh, T., Smith, C., Lamb, W. F., Lamboll, R., Cassou, C., Hauser, M., Hausfather, Z., Lee, J.-Y., Palmer, M. D., von Schuckmann, K., Slangen, A. B. A., Szopa, S., Trewin, B., Yun, J., Gillett, N. P., Jenkins, S., Matthews, H. D., Raghavan, K., Ribes, A., Rogelj, J., Rosen, D., Zhang, X., Allen, M., Andrew, R. M., Atkinson, C., Betts, R. A., Bombelli, A., Burgess, S. N., Cheng, L., Claxton, H. E., Friedlingstein, P., Frölicher, T. L., Domingues, C. M., Gasser, T., Gregory, C. H., Hoesly, R. M., Huppmann, D., Ishii, M., Kadow, C., Karwat, A., Kennedy, J., Killick, R. E., Kovilakam, M. V. M., Krummel, P. B., Lan, X., Lamarque, J.-F., Liné, A., Martín-Míguez, B., Monselesan, D. P., Morice, C., Mühle, J., Mussak, P., Peters, G. P., Pirani, A., Pongratz, J., Rigby, M., Rohde, R., Savita, A., Seneviratne, S. I., Smith, S. J., Taha, G., Tassone, C., Thorne, P., Wells, C., Western, L. M., van der Werf, G. R., Wijffels, S. E., Zecchetto, M., Zhong, J., Zhang, X.-Y., Masson-Delmotte, V., and Zhai, P.: Indicators of Global Climate Change 2025: annual update of key indicators of the state of the climate system and human influence, Earth Syst. Sci. Data, 18, 3889–3933, https://doi.org/10.5194/essd-18-3889-2026, 2026. Smith, C., Walsh, T., Gillett, N., Hauser, M., Krummel, P., Lamb, W., Lamboll, R., Mühle, J., Palmer, M., Ribes, A., Schumacher, D., Seneviratne, S., Slangen, A., Trewin, B., von Schuckmann, K., & Forster, P. (2026). Indicators of Global Climate Change 2025 (Version IGCC-2025a) [Computer software]. Zenodo. https://doi.org/10.5281/ZENODO.21494229
- Producer
- Indicators of Global Climate Change (IGCC) consortium, led by the University of Leeds · Indicators of Global Climate Change 2025
- Version
- IGCC-2025a
- Fetched
- 2026-10-04 (automatically), 683 bytes
- Fingerprint
- sha256 d419c3f7d513b42052f5635454853610739d8b5f1749f55b5df03862dfe28879ETag W/"9a20ce76744835485a38171386d4a8dfd0b83afea59b1c94a596a809ea375aee"
- Copies
- No Wayback copy recorded yet.Our copy of the exact file
- Cite the producer
- Forster, P. M., Walsh, T., Smith, C., Lamb, W. F., Lamboll, R., Cassou, C., Hauser, M., Hausfather, Z., Lee, J.-Y., Palmer, M. D., von Schuckmann, K., Slangen, A. B. A., Szopa, S., Trewin, B., Yun, J., Gillett, N. P., Jenkins, S., Matthews, H. D., Raghavan, K., Ribes, A., Rogelj, J., Rosen, D., Zhang, X., Allen, M., Andrew, R. M., Atkinson, C., Betts, R. A., Bombelli, A., Burgess, S. N., Cheng, L., Claxton, H. E., Friedlingstein, P., Frölicher, T. L., Domingues, C. M., Gasser, T., Gregory, C. H., Hoesly, R. M., Huppmann, D., Ishii, M., Kadow, C., Karwat, A., Kennedy, J., Killick, R. E., Kovilakam, M. V. M., Krummel, P. B., Lan, X., Lamarque, J.-F., Liné, A., Martín-Míguez, B., Monselesan, D. P., Morice, C., Mühle, J., Mussak, P., Peters, G. P., Pirani, A., Pongratz, J., Rigby, M., Rohde, R., Savita, A., Seneviratne, S. I., Smith, S. J., Taha, G., Tassone, C., Thorne, P., Wells, C., Western, L. M., van der Werf, G. R., Wijffels, S. E., Zecchetto, M., Zhong, J., Zhang, X.-Y., Masson-Delmotte, V., and Zhai, P.: Indicators of Global Climate Change 2025: annual update of key indicators of the state of the climate system and human influence, Earth Syst. Sci. Data, 18, 3889–3933, https://doi.org/10.5194/essd-18-3889-2026, 2026. Smith, C., Walsh, T., Gillett, N., Hauser, M., Krummel, P., Lamb, W., Lamboll, R., Mühle, J., Palmer, M., Ribes, A., Schumacher, D., Seneviratne, S., Slangen, A., Trewin, B., von Schuckmann, K., & Forster, P. (2026). Indicators of Global Climate Change 2025 (Version IGCC-2025a) [Computer software]. Zenodo. https://doi.org/10.5281/ZENODO.21494229
- Producer
- Indicators of Global Climate Change (IGCC) consortium, led by the University of Leeds · Indicators of Global Climate Change 2025
- Version
- IGCC-2025a
- Fetched
- 2026-10-04 (automatically), 202,355 bytes
- Fingerprint
- sha256 ecf9da410624bb9959d38b916be9d6dde6c0a6613a640c2ef842c464f71d146aETag W/"6584d631ed4a225dc7e0c2ebb9b3565b92130307ee6a5e2e0096c08faeb211e2"
- Copies
- No Wayback copy recorded yet.Our copy of the exact file
- Cite the producer
- Forster, P. M., Walsh, T., Smith, C., Lamb, W. F., Lamboll, R., Cassou, C., Hauser, M., Hausfather, Z., Lee, J.-Y., Palmer, M. D., von Schuckmann, K., Slangen, A. B. A., Szopa, S., Trewin, B., Yun, J., Gillett, N. P., Jenkins, S., Matthews, H. D., Raghavan, K., Ribes, A., Rogelj, J., Rosen, D., Zhang, X., Allen, M., Andrew, R. M., Atkinson, C., Betts, R. A., Bombelli, A., Burgess, S. N., Cheng, L., Claxton, H. E., Friedlingstein, P., Frölicher, T. L., Domingues, C. M., Gasser, T., Gregory, C. H., Hoesly, R. M., Huppmann, D., Ishii, M., Kadow, C., Karwat, A., Kennedy, J., Killick, R. E., Kovilakam, M. V. M., Krummel, P. B., Lan, X., Lamarque, J.-F., Liné, A., Martín-Míguez, B., Monselesan, D. P., Morice, C., Mühle, J., Mussak, P., Peters, G. P., Pirani, A., Pongratz, J., Rigby, M., Rohde, R., Savita, A., Seneviratne, S. I., Smith, S. J., Taha, G., Tassone, C., Thorne, P., Wells, C., Western, L. M., van der Werf, G. R., Wijffels, S. E., Zecchetto, M., Zhong, J., Zhang, X.-Y., Masson-Delmotte, V., and Zhai, P.: Indicators of Global Climate Change 2025: annual update of key indicators of the state of the climate system and human influence, Earth Syst. Sci. Data, 18, 3889–3933, https://doi.org/10.5194/essd-18-3889-2026, 2026. Smith, C., Walsh, T., Gillett, N., Hauser, M., Krummel, P., Lamb, W., Lamboll, R., Mühle, J., Palmer, M., Ribes, A., Schumacher, D., Seneviratne, S., Slangen, A., Trewin, B., von Schuckmann, K., & Forster, P. (2026). Indicators of Global Climate Change 2025 (Version IGCC-2025a) [Computer software]. Zenodo. https://doi.org/10.5281/ZENODO.21494229
- Producer
- Indicators of Global Climate Change (IGCC) consortium, led by the University of Leeds · Indicators of Global Climate Change 2025
- Version
- IGCC-2025a
- Fetched
- 2026-10-04 (automatically), 46,521 bytes
- Fingerprint
- sha256 e0abdbb899df3b4b241336fdfd5c07e2eee2a8057ad31e323bd137a2c687d2feETag W/"7e509eb88cc88ccbe50175d03980b983776fea0c55b54a37cd5ac04fca12f60e"
- Copies
- No Wayback copy recorded yet.Our copy of the exact file
- Cite the producer
- Forster, P. M., Walsh, T., Smith, C., Lamb, W. F., Lamboll, R., Cassou, C., Hauser, M., Hausfather, Z., Lee, J.-Y., Palmer, M. D., von Schuckmann, K., Slangen, A. B. A., Szopa, S., Trewin, B., Yun, J., Gillett, N. P., Jenkins, S., Matthews, H. D., Raghavan, K., Ribes, A., Rogelj, J., Rosen, D., Zhang, X., Allen, M., Andrew, R. M., Atkinson, C., Betts, R. A., Bombelli, A., Burgess, S. N., Cheng, L., Claxton, H. E., Friedlingstein, P., Frölicher, T. L., Domingues, C. M., Gasser, T., Gregory, C. H., Hoesly, R. M., Huppmann, D., Ishii, M., Kadow, C., Karwat, A., Kennedy, J., Killick, R. E., Kovilakam, M. V. M., Krummel, P. B., Lan, X., Lamarque, J.-F., Liné, A., Martín-Míguez, B., Monselesan, D. P., Morice, C., Mühle, J., Mussak, P., Peters, G. P., Pirani, A., Pongratz, J., Rigby, M., Rohde, R., Savita, A., Seneviratne, S. I., Smith, S. J., Taha, G., Tassone, C., Thorne, P., Wells, C., Western, L. M., van der Werf, G. R., Wijffels, S. E., Zecchetto, M., Zhong, J., Zhang, X.-Y., Masson-Delmotte, V., and Zhai, P.: Indicators of Global Climate Change 2025: annual update of key indicators of the state of the climate system and human influence, Earth Syst. Sci. Data, 18, 3889–3933, https://doi.org/10.5194/essd-18-3889-2026, 2026. Smith, C., Walsh, T., Gillett, N., Hauser, M., Krummel, P., Lamb, W., Lamboll, R., Mühle, J., Palmer, M., Ribes, A., Schumacher, D., Seneviratne, S., Slangen, A., Trewin, B., von Schuckmann, K., & Forster, P. (2026). Indicators of Global Climate Change 2025 (Version IGCC-2025a) [Computer software]. Zenodo. https://doi.org/10.5281/ZENODO.21494229
- Producer
- Indicators of Global Climate Change (IGCC) consortium, led by the University of Leeds · Indicators of Global Climate Change 2025
- Version
- IGCC-2025a
- Fetched
- 2026-10-04 (automatically), 30,591 bytes
- Fingerprint
- sha256 5eb8a8883085cccce2330558ec6d0803a3638e40e6b799dd83c6ad67a4e835dfETag W/"80268af92a87e7d751f1361e59f301ba96b45f539e6db36442017a7232384b7d"
- Copies
- No Wayback copy recorded yet.Our copy of the exact file
- Cite the producer
- Forster, P. M., Walsh, T., Smith, C., Lamb, W. F., Lamboll, R., Cassou, C., Hauser, M., Hausfather, Z., Lee, J.-Y., Palmer, M. D., von Schuckmann, K., Slangen, A. B. A., Szopa, S., Trewin, B., Yun, J., Gillett, N. P., Jenkins, S., Matthews, H. D., Raghavan, K., Ribes, A., Rogelj, J., Rosen, D., Zhang, X., Allen, M., Andrew, R. M., Atkinson, C., Betts, R. A., Bombelli, A., Burgess, S. N., Cheng, L., Claxton, H. E., Friedlingstein, P., Frölicher, T. L., Domingues, C. M., Gasser, T., Gregory, C. H., Hoesly, R. M., Huppmann, D., Ishii, M., Kadow, C., Karwat, A., Kennedy, J., Killick, R. E., Kovilakam, M. V. M., Krummel, P. B., Lan, X., Lamarque, J.-F., Liné, A., Martín-Míguez, B., Monselesan, D. P., Morice, C., Mühle, J., Mussak, P., Peters, G. P., Pirani, A., Pongratz, J., Rigby, M., Rohde, R., Savita, A., Seneviratne, S. I., Smith, S. J., Taha, G., Tassone, C., Thorne, P., Wells, C., Western, L. M., van der Werf, G. R., Wijffels, S. E., Zecchetto, M., Zhong, J., Zhang, X.-Y., Masson-Delmotte, V., and Zhai, P.: Indicators of Global Climate Change 2025: annual update of key indicators of the state of the climate system and human influence, Earth Syst. Sci. Data, 18, 3889–3933, https://doi.org/10.5194/essd-18-3889-2026, 2026. Smith, C., Walsh, T., Gillett, N., Hauser, M., Krummel, P., Lamb, W., Lamboll, R., Mühle, J., Palmer, M., Ribes, A., Schumacher, D., Seneviratne, S., Slangen, A., Trewin, B., von Schuckmann, K., & Forster, P. (2026). Indicators of Global Climate Change 2025 (Version IGCC-2025a) [Computer software]. Zenodo. https://doi.org/10.5281/ZENODO.21494229
What was done to it
Checked that each file read (Assessment-Update-2025_GMST_headlines.csv, Gillett_GMST_timeseries.csv, Ribes_GMST_timeseries.csv, Walsh_GMST_timeseries.csv) is byte-identical to the same path inside the IGCC-2025a release zip deposited on Zenodo (doi:10.5281/zenodo.21494229, sha256 04658ff91053…).
Code: pipeline/src/envdash/transforms/climate/igcc_2025.py · code sha256 5a1f11a945b695d3… · inputs 04658ff91053… d419c3f7d513… ecf9da410624… e0abdbb899df… 5eb8a8883085…
Read the annual 5th, 50th and 95th percentiles of human-induced (anthropogenic) warming relative to 1850–1900 from the timeseries files of the three attribution methods IGCC assesses: Global Warming Index (Walsh), regularised optimal fingerprinting (Gillett) and kriging for climate change (Ribes).
Code: pipeline/src/envdash/transforms/climate/igcc_2025.py · code sha256 5a1f11a945b695d3… · inputs 04658ff91053… d419c3f7d513… ecf9da410624… e0abdbb899df… 5eb8a8883085…
Applied IGCC's stated assessment rule to every year (ESSD Sect. 8): the best estimate is the mean of the three medians to 0.01 °C (rounded half up), and the likely range runs from the lowest 5th percentile rounded down to 0.1 °C to the highest 95th percentile rounded up to 0.1 °C.
Code: pipeline/src/envdash/transforms/climate/igcc_2025.py · code sha256 5a1f11a945b695d3… · inputs 04658ff91053… d419c3f7d513… ecf9da410624… e0abdbb899df… 5eb8a8883085…
Checked that this reproduces every single-year annual-mean assessment IGCC published in Assessment-Update-2025_GMST_headlines.csv (2017: 1.14 [0.9 to 1.4] °C; 2025: 1.38 [1.1 to 1.7] °C); it does, exactly. IGCC's headline single-year figure uses the trend-based definition of the IPCC 1.5 °C report instead, which IGCC prioritises where the two differ; it is published as warming.igcc-2025.human-induced-2025, not in this series.
Code: pipeline/src/envdash/transforms/climate/igcc_2025.py · code sha256 5a1f11a945b695d3… · inputs 04658ff91053… d419c3f7d513… ecf9da410624… e0abdbb899df… 5eb8a8883085…
What it covers
- Geography
- Global mean
- Baseline
- 1850–1900
- Basis
- Global mean surface temperature (GMST); warming attributed to all human influences (greenhouse gases, aerosols and other human forcings), annual-mean definition. Best estimate: mean of the three methods' medians to 0.01 °C. Likely range: the smallest 0.1 °C-step range covering each method's 5–95% range.
- Unit
- degrees Celsius (°C)