Scale 03 / EarthStatus: ActiveReviewed 2026-10

Climate change

427.55ppm

Parts per million (ppm) of carbon dioxide in the air at Mauna Loa, Hawaii, monthly average, August 2026. Uncertainty ± 0.17 ppm.^{Source 1}

Monthly averages rise and fall with the seasons, so compare the same month across years.

That is about 1.5 times the level in 1750, before the Industrial Revolution.Derived

What it is

Climate change is the long-term warming of the planet and the changes that come with it. Gases such as carbon dioxide trap heat. Since the start of the industrial era, human activity has pushed their levels in the air up, and the Intergovernmental Panel on Climate Change (IPCC), the United Nations body that assesses climate science, finds it is unequivocal that human influence has warmed the atmosphere, ocean and land.^{Source 4}

How big it is

The air now holds 427.55 ppm (± 0.17) in August 2026^{Source 1} of carbon dioxide, measured at Mauna Loa Observatory in Hawaii. Ice cores show it held 278.3 ppm (± 2.9) in 1750^{Source 2} before industrialisation.

The planet has warmed with it. NASA’s record shows global average surface temperature was 1.19 °C in 2025^{Source 3} above its mid-twentieth-century baseline.

Global surface temperature compared with the 1951–1980 average

From 1880 to 2025. Lowest: -0.49 °C in 1909. Highest: 1.29 °C in 2024. Latest: 1.19 °C in 2025.

Zero is the 1951–1980 average, the baseline NASA uses; values above zero are warmer than it. Source: GISTEMP Team, NASA Goddard Institute for Space Studies, GISS Surface Temperature Analysis (GISTEMP), version 4^{Source 3}. Data through 2025. License: US government work.

Show data table

Global surface temperature compared with the 1951–1980 average
Year	Global surface temperature compared with the 1951–1980 average (°C)
1880	-0.18
1881	-0.09
1882	-0.12
1883	-0.18
1884	-0.29
1885	-0.34
1886	-0.32
1887	-0.37
1888	-0.18
1889	-0.11
1890	-0.36
1891	-0.23
1892	-0.28
1893	-0.32
1894	-0.31
1895	-0.23
1896	-0.12
1897	-0.12
1898	-0.28
1899	-0.18
1900	-0.09
1901	-0.16
1902	-0.29
1903	-0.38
1904	-0.48
1905	-0.27
1906	-0.23
1907	-0.39
1908	-0.43
1909	-0.49
1910	-0.44
1911	-0.45
1912	-0.37
1913	-0.36
1914	-0.17
1915	-0.15
1916	-0.37
1917	-0.46
1918	-0.30
1919	-0.28
1920	-0.28
1921	-0.19
1922	-0.29
1923	-0.27
1924	-0.27
1925	-0.22
1926	-0.11
1927	-0.22
1928	-0.20
1929	-0.36
1930	-0.16
1931	-0.09
1932	-0.16
1933	-0.29
1934	-0.13
1935	-0.20
1936	-0.15
1937	-0.03
1938	-0.01
1939	-0.02
1940	0.12
1941	0.18
1942	0.06
1943	0.09
1944	0.20
1945	0.09
1946	-0.07
1947	-0.03
1948	-0.11
1949	-0.11
1950	-0.18
1951	-0.07
1952	0.01
1953	0.08
1954	-0.13
1955	-0.14
1956	-0.19
1957	0.05
1958	0.06
1959	0.03
1960	-0.02
1961	0.06
1962	0.03
1963	0.05
1964	-0.20
1965	-0.11
1966	-0.06
1967	-0.02
1968	-0.08
1969	0.05
1970	0.03
1971	-0.08
1972	0.01
1973	0.16
1974	-0.07
1975	-0.01
1976	-0.10
1977	0.18
1978	0.07
1979	0.16
1980	0.26
1981	0.32
1982	0.14
1983	0.31
1984	0.16
1985	0.12
1986	0.18
1987	0.32
1988	0.39
1989	0.27
1990	0.45
1991	0.41
1992	0.22
1993	0.23
1994	0.32
1995	0.45
1996	0.33
1997	0.47
1998	0.61
1999	0.38
2000	0.39
2001	0.53
2002	0.63
2003	0.62
2004	0.53
2005	0.68
2006	0.64
2007	0.66
2008	0.54
2009	0.66
2010	0.72
2011	0.61
2012	0.65
2013	0.68
2014	0.75
2015	0.90
2016	1.01
2017	0.92
2018	0.85
2019	0.98
2020	1.01
2021	0.85
2022	0.89
2023	1.17
2024	1.29
2025	1.19

Where it’s heading

Carbon dioxide is still rising. In the same month ten years earlier, Mauna Loa measured 402.45 ppm (± 0.23) in August 2016^{Source 1}.

The IPCC finds that global surface temperature will keep rising until at least the middle of this century under every emissions scenario it considered.^{Source 4}

What works

From a physical science point of view, the IPCC finds that stopping warming at any level requires limiting the total carbon dioxide we emit, reaching at least net zero carbon dioxide emissions, and making strong cuts to other greenhouse gases.^{Source 4}

What you can do

Learn

Read the IPCC's Summary for Policymakers Editorial
The Intergovernmental Panel on Climate Change's own short summary of the physical science.
Follow the carbon dioxide record as it updates Editorial
NOAA publishes the Mauna Loa measurements every month.

More detail

Why Mauna Loa?

The record combines measurements by the Scripps Institution of Oceanography, which started it, with NOAA’s measurements that followed. When a volcanic eruption cut off Mauna Loa Observatory, NOAA measured from a site on nearby Maunakea until it could return.

^{Source 1}

Why NASA's baseline isn't “pre-industrial”

NASA compares each year with the average of a mid-twentieth-century period. Figures you may see for warming since before industrialisation use an earlier, cooler baseline, so they are larger. The chart shows this: the earliest years sit below zero.

^{Source 3}

How certain are these numbers?

NOAA states an uncertainty for each monthly carbon dioxide average, shown next to the number. NASA estimates the uncertainty of its temperature record with a separate ensemble of possible reconstructions. ^{Source 5} That ensemble doesn’t yet cover the latest years, so no range is shown for them.

Sources

Tier 1NOAA Global Monitoring Laboratory and Scripps Institution of Oceanography (Xin Lan, NOAA GML; Ralph Keeling, Scripps). Mauna Loa CO₂ monthly mean data (2026). File co2_mm_mlo.txt (file creation 5 September 2026), columns “monthly average” and “unc. of mon mean”. Archived copy of source 1, accessed 2026-10-06. License: Freely available; NOAA GML asks users to credit the data providers (file header, “USE OF NOAA GML DATA”).
Tier 1Gulev, S.K., P.W. Thorne, J. Ahn et al. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the IPCC. Cambridge University Press. Chapter 2: Changing State of the Climate System (2021). Section 2.2.3.2.1, p. 300: “CO2 concentrations of 278.3 ± 2.9 ppm in 1750”. Archived copy of source 2, accessed 2026-10-06.
Tier 1GISTEMP Team, NASA Goddard Institute for Space Studies. GISS Surface Temperature Analysis (GISTEMP), version 4 (2026). File GLB.Ts+dSST.csv (global land-ocean temperature index), column J-D: January–December mean, °C relative to the 1951–1980 average. Archived copy of source 3, accessed 2026-10-06. License: US government work.
Tier 1IPCC. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the IPCC. Cambridge University Press, pp. 3–32. Summary for Policymakers (2021). Statements A.1 and A.1.1 (p. 4), B.1 (p. 14) and D.1 (p. 27). Archived copy of source 4, accessed 2026-10-06.
Tier 1Lenssen, N., G.A. Schmidt, M. Hendrickson, P. Jacobs, M. Menne and R. Ruedy. Journal of Geophysical Research: Atmospheres, 129(17), e2023JD040179. A NASA GISTEMPv4 observational uncertainty ensemble (2024). Whole paper; ensemble period described on https://data.giss.nasa.gov/gistemp/uncertainty/. Archived copy of source 5, accessed 2026-10-06.