Climate Change: What the Scientific Record Shows
The documented warming
Global average surface temperature is now roughly 1.1 to 1.5 degrees Celsius above late-nineteenth-century levels, depending on the data set, baseline and averaging period used. This is documented by multiple independent data sets from different countries and methodologies, including surface stations, ocean buoys, weather balloons and satellites.
The rate of warming has accelerated since the mid-twentieth century, corresponding with the large-scale industrialisation of the global economy. The link between atmospheric CO2 concentration and temperature shows up in ice cores covering roughly the last 800,000 years, in sediment records reaching back much further, and in modern direct measurement.
The scientific consensus
The Intergovernmental Panel on Climate Change assesses published research on behalf of its member governments, and its reports are written and reviewed by thousands of scientists. Its sixth assessment report states that it is unequivocal that human influence has warmed the atmosphere, ocean and land.
This conclusion is not the property of one country or institution. NASA lists statements of agreement from scientific organisations including the American Geophysical Union, the American Physical Society and the U.S. National Academy of Sciences, and no scientific body of national or international standing disagrees.
What is disputed and what isn't
The fact of warming, and its primary human cause, are not scientifically disputed among climate researchers. What is genuinely debated includes the precise sensitivity of the climate to a doubling of CO2, the regional distribution of specific impacts, the feedback mechanisms that will determine the pace of future change, and the relative effectiveness of different mitigation strategies.
The policy response to climate change, which involves trade-offs between economic interests, timescales and national priorities, is legitimately contested. The physical science is not.
Sources and further reading
Pages we consulted when writing and revising this article, last checked October 8, 2026. They open in a new tab, and we are not responsible for what other sites publish.
- Scientific consensus on climate change — NASA Science — statements from scientific organisations.
- Scientific consensus on climate change — Wikipedia — survey and IPCC findings.
Written with AI assistance and prepared for publication under our editorial policy. Spotted a mistake? Tell us and we will check it.
