You don't have to take anyone's word for it. Here is the data, straight from the agencies that measure it — and what each chart shows.
By Andreas Marshall · Last reviewed 17 October 2026 · Every claim is linked to its source below.
1. The planet is warming
Independent records from NASA and Copernicus show the same thing: the last 12 months were1.51 °C warmer than the late 19th century, and 2024 was the hottest year on record.
Global temperature, annual average (°C above 1850–1900)
NASA GISTEMP (vs 1880–1900)Copernicus ERA5
ERA5 anomalies converted to 1850–1900 using Copernicus' standard +0.88 °C offset. GISTEMP rebased to its earliest years, 1880–1900.
2. CO₂ is at its highest in millions of years
Direct measurements since 1958 show CO₂ rising from about 316 ppm to 427 ppm today. Ice cores show it never exceeded about 300 ppm in the 800,000 years before industrialisation.
The Keeling curve: CO₂ at Mauna Loa (ppm)
Monthly meanSeasonally adjusted
3. Humans explain all of it — nature explains none
The IPCC attributed the warming of 2010–2019 to its causes. Greenhouse gases alone would have warmed the planet by about 1.5 °C; air pollution (aerosols) masked part of that. Natural factors — the sun and volcanoes — contributed roughly zero.
Contributions to warming in 2010–2019 vs 1850–1900 (°C)
Source: IPCC AR6 WG1 SPM A.1.3 and Figure SPM.2. Bars show the likely range.
4. Arctic ice is shrinking
Arctic sea ice in September, 1979 to today (million km²)
Ten-day values, seasonal cycle removed, average across the missions available at each time. Not corrected for glacial isostatic adjustment.
6. Every year, a stripe
1880 → 2025. Each stripe is one year's average global temperature, from blue (cooler) to red (warmer). Data: NASA GISTEMP v4. Concept: Ed Hawkins, #ShowYourStripes.
What it means
Each of these records is measured by different instruments, by different teams, in different countries. They all point the same way. That is why the IPCC — summarising thousands of studies, reviewed by governments — states that human influence has warmed the climate unequivocally.
The open questions in climate science today are not whether warming is happening, but how fast, where, and how much we choose to limit it. See what 1.5 °C means.
Frequently asked questions
Is climate change real?
Yes. Thermometers, satellites, ocean buoys, ice cores and tide gauges independently show the planet has warmed by about 1.3 °C since the late 1800s. The IPCC calls the warming “unequivocal”, and NASA, NOAA, the UK Met Office, Japan's JMA and Europe's Copernicus all find the same trend.
How do we know humans are causing it?
CO₂ has risen about 50% since pre-industrial times, and its chemical fingerprint (isotopes) shows it comes from fossil fuels. Physics has predicted the warming effect of CO₂ since the 19th century, and natural factors such as the sun and volcanoes explain essentially none of the warming since 1850–1900 (IPCC AR6).
Isn't it just the sun?
No. Satellites have measured the sun's output since 1978, and it has been flat or slightly declining while temperatures rose. If the sun were responsible, the upper atmosphere would also warm — instead it is cooling, which is what greenhouse warming predicts.
The climate has always changed — why is this different?
Past changes were driven by slow variations in Earth's orbit, volcanic activity or the sun, and usually unfolded over thousands of years. Today's warming is happening far faster, and it tracks the rise in greenhouse gases that we are emitting.
CO₂ is only 0.04% of the atmosphere — how can it matter?
Small concentrations can have big effects. Nitrogen and oxygen, 99% of the air, do not absorb heat radiation; CO₂ does. Its warming effect has been measured in the laboratory since the 1850s and observed from satellites, which see less heat escaping to space at exactly the wavelengths CO₂ absorbs.
Do scientists agree on climate change?
Yes. A 2021 review of 88,125 peer-reviewed studies found more than 99% agree that recent warming is mainly caused by humans (Lynas et al.). Every major national science academy endorses this conclusion.