Albedo Weekly

Research library · updated 24 October 2026

What the research says about global warming

The latest figures from the world's climate agencies and assessment reports, in plain language, each linked to its source.

Measuring melt ponds on Arctic sea ice
Fig. 1 · Researchers measure melt ponds on Arctic sea ice, where melting lowers the albedo. Photo: NASA Goddard Space Flight Center, Public domain, via Wikimedia Commons
1880: -0.17 °C1881: -0.09 °C1882: -0.11 °C1883: -0.18 °C1884: -0.28 °C1885: -0.33 °C1886: -0.31 °C1887: -0.36 °C1888: -0.18 °C1889: -0.11 °C1890: -0.36 °C1891: -0.22 °C1892: -0.27 °C1893: -0.31 °C1894: -0.30 °C1895: -0.23 °C1896: -0.11 °C1897: -0.11 °C1898: -0.28 °C1899: -0.18 °C1900: -0.08 °C1901: -0.16 °C1902: -0.28 °C1903: -0.37 °C1904: -0.47 °C1905: -0.26 °C1906: -0.22 °C1907: -0.38 °C1908: -0.42 °C1909: -0.48 °C1910: -0.44 °C1911: -0.44 °C1912: -0.37 °C1913: -0.34 °C1914: -0.15 °C1915: -0.14 °C1916: -0.36 °C1917: -0.46 °C1918: -0.30 °C1919: -0.27 °C1920: -0.27 °C1921: -0.18 °C1922: -0.28 °C1923: -0.26 °C1924: -0.27 °C1925: -0.22 °C1926: -0.11 °C1927: -0.22 °C1928: -0.20 °C1929: -0.36 °C1930: -0.15 °C1931: -0.09 °C1932: -0.16 °C1933: -0.28 °C1934: -0.13 °C1935: -0.20 °C1936: -0.15 °C1937: -0.03 °C1938: +0.00 °C1939: -0.02 °C1940: +0.12 °C1941: +0.18 °C1942: +0.06 °C1943: +0.09 °C1944: +0.20 °C1945: +0.09 °C1946: -0.07 °C1947: -0.03 °C1948: -0.11 °C1949: -0.11 °C1950: -0.17 °C1951: -0.07 °C1952: +0.01 °C1953: +0.08 °C1954: -0.13 °C1955: -0.14 °C1956: -0.19 °C1957: +0.05 °C1958: +0.06 °C1959: +0.03 °C1960: -0.02 °C1961: +0.06 °C1962: +0.03 °C1963: +0.05 °C1964: -0.20 °C1965: -0.11 °C1966: -0.06 °C1967: -0.02 °C1968: -0.08 °C1969: +0.05 °C1970: +0.03 °C1971: -0.08 °C1972: +0.01 °C1973: +0.16 °C1974: -0.07 °C1975: -0.01 °C1976: -0.10 °C1977: +0.18 °C1978: +0.07 °C1979: +0.16 °C1980: +0.26 °C1981: +0.32 °C1982: +0.14 °C1983: +0.31 °C1984: +0.16 °C1985: +0.12 °C1986: +0.18 °C1987: +0.32 °C1988: +0.39 °C1989: +0.27 °C1990: +0.45 °C1991: +0.41 °C1992: +0.22 °C1993: +0.23 °C1994: +0.31 °C1995: +0.45 °C1996: +0.33 °C1997: +0.47 °C1998: +0.61 °C1999: +0.38 °C2000: +0.39 °C2001: +0.53 °C2002: +0.63 °C2003: +0.62 °C2004: +0.53 °C2005: +0.68 °C2006: +0.64 °C2007: +0.66 °C2008: +0.54 °C2009: +0.66 °C2010: +0.72 °C2011: +0.61 °C2012: +0.65 °C2013: +0.67 °C2014: +0.75 °C2015: +0.89 °C2016: +1.01 °C2017: +0.91 °C2018: +0.85 °C2019: +0.98 °C2020: +1.01 °C2021: +0.85 °C2022: +0.89 °C2023: +1.17 °C2024: +1.28 °C2025: +1.18 °C
One stripe per year, 1880–2025: global surface temperature compared with the 1951–1980 average. 2025: +1.18 °C. Data: NASA GISS, GISTEMP v4.

2026 so far (January to month 9): +1.23 °C against the same baseline.

Line chart of global surface temperature change from 1880 to 2025
Fig. 2 · Global surface temperature change against the 1951–1980 average. Data: NASA GISS, GISTEMP v4

Key indicators

Global mean temperature 2025 (consolidated, 8 datasets)

1.43 °C above baseline (±0.13)

2025 · 1850-1900

World Meteorological Organization · State of the Global Climate 2025

Global temperature anomaly 2025 (GISTEMP)

1.19 °C above baseline

2025 · 1951-1980

NASA · NASA releases global temperature data

Global temperature anomaly 2025 (NOAAGlobalTemp)

1.17 °C above baseline

2025 · 20th-century average

NOAA NCEI · Global Climate Report - Annual 2025

Global temperature anomaly 2025

1.44 °C above baseline (±0.09)

2025 · 1850-1900

Berkeley Earth · Global Temperature Report for 2025

Fossil CO2 emissions 2025

10.4 GtC

2025 · 2024: 10.3 ±0.5 GtC

Global Carbon Project · Global Carbon Budget 2025

Human-induced warming 2025

1.37 °C above 1850-1900

2025 · 1850-1900

Forster et al. / IGCC · Indicators of Global Climate Change 2025

Human-induced warming rate

0.27 °C per decade (likely 0.2-0.4)

2016-2025

Forster et al. / IGCC · Indicators of Global Climate Change 2025

Greenhouse gas emissions (all gases)

56.8 GtCO2e

2024 · 10-year mean 2015-2024: 54.6 ±5.5

Forster et al. / IGCC · Indicators of Global Climate Change 2025

Global mean sea level rise in 2025

0.08 cm in the year (0.59 cm in 2024)

2025 · Since 1993: about 10 cm

NASA · La Nina limited sea level rise in 2025

Arctic sea ice minimum 2026

4.6 million km²

2026-09-12

NASA / NSIDC · Arctic sea ice 2026 minimum

Projected warming if NDCs fully implemented

2.3-2.5 °C by 2100

NDCs as of 2025 · Previous edition: 2.6-2.8 °C

UNEP · Emissions Gap Report 2025

Reef area hit by bleaching-level heat stress (4th global event)

84 percent

2023-01 to 2025-06

NOAA NESDIS / Coral Reef Watch · World's fourth mass coral bleaching event likely ended

The reports that matter

IPCC · 2023-03-20

IPCC AR6 Synthesis Report

  • Human activity has already warmed the planet by about 1.1 °C.
  • Emissions must roughly halve by 2030 to keep 1.5 °C within reach.
  • Deaths from floods, droughts and storms were 15 times higher in highly vulnerable regions.
  • Every increment of warming raises risk; delay narrows the options.

Read the report

IPCC · 2025-08-18

IPCC AR7 timeline

  • 664 authors from 111 countries were selected for the seventh cycle.
  • Working group reports are expected from mid-2028, the synthesis report by late 2029.
  • The 65th plenary in Addis Ababa (12-16 Oct 2026) was suspended with timelines and budget unresolved.
  • Special Report on Climate Change and Cities due around March 2027 (secondary: unverified).

Read the report

WMO · 2026-03-23

State of the Global Climate 2025

  • 2025 ran about 1.43 °C above pre-industrial; the eleven warmest years are 2015-2025.
  • Ocean heat content hit a record and takes up about 91% of the energy imbalance.
  • Sea level rises about 4.1 mm a year, double the early-1990s pace.
  • Arctic winter ice peaked at a record low; glaciers lost mass again.

Read the report

Copernicus Climate Change Service · 2026-01-14

Global Climate Highlights 2025

  • 2025 was the third warmest year at 1.47 °C above pre-industrial.
  • The 2023-2025 average passed 1.5 °C for the first time.
  • Long-term warming is now around 1.4 °C.
  • Extrapolar sea surface temperature was third highest on record.

Read the report

Global Carbon Project · 2026-05-13

Global Carbon Budget 2025

  • Fossil CO2 grew about 1.0% in 2025 to roughly 10.4 GtC, a new high.
  • Atmospheric CO2 reached 425.6 ppm, 53% above pre-industrial.
  • Ocean and land sinks absorbed about half of emissions (29% and 21%, secondary).
  • Remaining 1.5 °C budget is a few years of emissions (secondary: unverified).

Read the report

UNEP · 2025-11-04

UNEP Emissions Gap Report 2025

  • Full delivery of national pledges points to 2.3-2.5 °C, an improvement on last year.
  • Current policies still lead to up to 2.8 °C.
  • 2035 pledges cut emissions only about 15% from 2019; 55% is needed for 1.5 °C.
  • Many countries had not filed 2035 targets by the cut-off date.

Read the report

Forster et al., Earth System Science Data · 2026-06-11

Indicators of Global Climate Change 2025 (IGCC)

  • Human-induced warming reached 1.37 °C in 2025, rising about 0.27 °C per decade.
  • Greenhouse gas emissions were about 56.8 GtCO2e in 2024.
  • Earth's energy imbalance more than doubled compared with 1976-1995.
  • Marine heatwave days more than tripled since 1991.

Read the report

The Lancet / Lancet Countdown · 2025-10-29

Lancet Countdown 2025

  • Heat kills roughly half a million people a year, a rate up 23% since the 1990s.
  • Heat cost about 640 billion potential work hours.
  • Governments still net-subsidised fossil fuels by hundreds of billions of dollars.
  • Wildfire smoke was linked to about 154,000 deaths in 2024.

Read the report

American Meteorological Society / NOAA · 2026-08-10

State of the Climate in 2025 (BAMS)

  • 36th edition, 625 scientists from 60 countries.
  • CO2 reached 425.6 ppm; sea level about 111 mm above 1993, a record for the 14th year.
  • 87% of the ocean saw a marine heatwave.
  • Glaciers lost over 1 m water equivalent for the fourth year running.

Read the report

Climate Action Tracker · 2025-11-13

Climate Action Tracker Global Update 2025

  • Current policies give 2.6 °C, slightly better than last year.
  • Pledges and targets give 2.2 °C.
  • The gap to a 1.5 °C path grows from 29 to 31 GtCO2e between 2030 and 2035.

Read the report

Coming up

Open data

DatasetPublisherWhat it measuresUpdated
ERA5 reanalysisCopernicus C3S / ECMWFHourly global atmosphere, land and ocean fields since 1940monthly bulletin, daily data with about 5-day lag
GISTEMP v4NASA GISSGlobal surface temperature anomalies since 1880monthly
NOAAGlobalTempNOAA NCEIMerged land-ocean temperature recordmonthly
Berkeley Earth Land/OceanBerkeley EarthIndependent global temperature seriesmonthly
HadCRUT5UK Met Office Hadley Centre / UEA CRUGridded temperature anomaliesmonthly
Mauna Loa CO2 / global CO2NOAA GMLAtmospheric CO2 daily to annualdaily to monthly
Keeling CurveScripps Institution of OceanographyMauna Loa CO2 record since 1958daily
NOAA greenhouse gas CH4 and N2O trendsNOAA GMLGlobal methane and nitrous oxidemonthly
Global Carbon Budget dataGlobal Carbon ProjectEmissions, sinks and budget by countryannual (November)
Indicators of Global Climate Change dataForster et al. via ZenodoWarming, forcing, budget indicatorsannual (June)
Sea Ice IndexNSIDCDaily and monthly Arctic and Antarctic ice extentdaily
NASA Sea Level Change portalNASASatellite altimetry global mean sea levelabout every 2 months
Fluctuations of GlaciersWorld Glacier Monitoring ServiceGlacier mass balance and length changeannual
IMBIE ice sheet mass balanceIMBIE / ESA-NASAGreenland and Antarctic mass balanceirregular editions
Coral Reef WatchNOAASatellite heat stress and bleaching alertsdaily
EDGAREuropean Commission JRCGlobal emissions by country and sectorannual
Argo ocean dataArgo programmeProfiling float temperature and salinitycontinuous

How we work

We take every figure from the publishing agency or report, name the period and baseline, and link the source. Different agencies use different baselines, so their numbers are not added or mixed. Summaries are our own words.