How do CO2 levels today compare with the pre-industrial era?

CO2 is now about 146.3 ppm above the pre-industrial level, or roughly 1.52 times higher.

Key Facts

  • Today: 426.25 ppm
  • Pre-industrial: about 280 ppm
  • Increase: about 146.3 ppm

Graph

Explanation

The pre-industrial atmosphere contained about 280 ppm of CO2. That level was relatively stable for thousands of years before industrialization. Since the 19th century, burning coal, oil and gas, plus land-use changes, have increased atmospheric CO2 sharply. The difference between today and the pre-industrial era matters because CO2 persists in the atmosphere and continues to influence temperature, oceans and ecosystems.

Data Source

Source: NOAA Global Monitoring Laboratory (Mauna Loa)

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Last Updated

2026-09-10