Latest measurement:  December 2022

420 ppm

Carbon dioxide in the atmosphere warms the planet, causing climate change. Human activities have raised the atmosphere’s carbon dioxide content by 50% in less than 200 years.

Carbon dioxide (CO₂) is an important heat-trapping gas, or greenhouse gas, that comes from the extraction and burning of fossil fuels (such as coal, oil, and natural gas), from wildfires, and from natural processes like volcanic eruptions. Figure 1,  shows atmospheric CO₂ levels measured at Mauna Loa Observatory, Hawaii, in recent years, with natural, seasonal changes removed.

                                      Figure 1: CO2 levels increasing along the time.

The second graph shows CO₂ levels during Earth’s last three glacial cycles, as captured by air bubbles trapped in ice sheets and glaciers.

Since the beginning of industrial times (in the 18th century), human activities have raised atmospheric CO₂ by 50% – meaning the amount of CO₂ is now 150% of its value in 1750. This is greater than what naturally happened at the end of the last ice age 20,000 years ago.

                           Figure 2: CO2 levels during Earth´s last three glacial cycles.