How much more carbon dioxide is in the air now compared to 150 years ago?

Approximately 150 years ago, the concentration of carbon dioxide (CO2) in the atmosphere was around 280 parts per million (ppm). As of 2023, that level has risen to about 420 ppm, indicating an increase of approximately 140 ppm. This rise is largely attributed to human activities such as fossil fuel combustion and deforestation. The increase in CO2 levels is a significant factor contributing to climate change.