This value was recorded at the Mauna Loa Observatory, in Hawaii, according to Iflscience.com. This was backed by recordings from the National Oceanic and Atmospheric Administration (NOAA), their data showing levels reached 421.33 parts per million on May 4th, 2022.

Carbon dioxide is one of the greenhouse gases that influences climate change the most, because is stays in the atmosphere for centuries.

Although CO2 is naturally found in the Earth’s atmosphere, the concentration of this heat-trapping gas has been increasing since the Industrial Revolution in the 19th century as it’s released through human activities such as burning fossil fuels and deforestation.

Hawaii’s Mauna Loa Observatory is used as a global background reference for CO2 in the atmosphere because of its high altitude and remote location.

Measurements of carbon dioxide concentration have been carried out here since 1958, at that time the levels being less than 320 parts per million.

The last time global carbon dioxide levels were above 400 parts per million was about 4 million years ago, at a time when the temperatures were about 3 degrees Celsius higher, and also the sea levels were higher than today.