The evidence does not rely on one graph.
Each line of evidence is useful on its own. Together, they are much harder to dismiss.
The basic case in five steps
You do not need to trust one politician, one activist, one model or one weather event. The case comes from separate measurements that all point the same way.
Greenhouse gases trap heat.
Gases such as CO2 absorb infrared radiation, which slows heat leaving the planet.
Burning fossil fuels adds greenhouse gases.
Coal, oil and gas release carbon that was locked away for millions of years.
Atmospheric CO2 has risen sharply.
This is measured directly, not predicted, and the rise tracks industrial activity.
Earth is storing more heat.
Most of the extra energy is going into the oceans, where it is measured over time.
The warming pattern matches greenhouse gases.
It fits greenhouse physics better than the Sun, volcanoes or natural variation alone.
CO2 and temperature, on the same timeline
As the amount of CO2 in the air has risen, the global temperature has risen with it. The two are measured in completely different ways, by different instruments and different teams, yet they move together. Hover or tap along the chart to read the values for any year.
Approximate values, rounded from NASA, NOAA, the Met Office and the HadCRUT record. CO2 is the global average concentration. Temperature is the global average compared with the late 1800s. Use left and right arrow keys to step through the years when the chart is focused.
| Year | CO2 (ppm) | Temperature vs late 1800s (degrees C) |
|---|---|---|
| 1850 | 285 | -0.1 |
| 1870 | 288 | -0.1 |
| 1890 | 294 | -0.2 |
| 1910 | 300 | -0.3 |
| 1930 | 307 | -0.1 |
| 1950 | 312 | 0.0 |
| 1970 | 325 | +0.1 |
| 1990 | 354 | +0.4 |
| 2000 | 369 | +0.6 |
| 2010 | 389 | +0.9 |
| 2020 | 414 | +1.3 |
| 2024 | 423 | +1.5 |
Ten lines of evidence
Select any card to open it. Each one states what it proves and, just as important, what it does not.
The evidence chain
One physical step leads to the next. Select any link to read the detail.
Frequently asked
Independent measurements of temperature, ocean heat, ice, sea level and atmospheric CO2 all show warming, and the CO2 carries the fingerprint of fossil fuels.
No. The core case rests on physics and direct measurement. Models help estimate future risk but are not what proves warming is happening.