The amount of carbon dioxide in the air exceeded 411 parts per million during the month of May, which was the highest monthly level ever recorded, according to the National Oceanic and Atmospheric Administration as well as Scripps Institution of Oceanography.
Why it matters: Based on studies of historical levels of greenhouse gases in the air, this is also the highest level in human history.
The big picture: Carbon dioxide, or CO2, is the most important long-lived greenhouse gas, and human activities, primarily the burning of fossil fuels for energy, are adding more of it with each passing day. Scripps and NOAA monitor CO2 levels at the Mauna Loa Observatory in Hawaii as well as other locations.
- This year, the May average peaked at 411.31 ppm, according to Scripps researchers, the organization reported in a press release. NOAA’s reading was 411.25 for the month, according to a press release.
In addition, the growth rate of CO2 in the atmosphere is increasing, NOAA data shows.
- The rate of growth averaged about 1.6 ppm per year in the 1980s, and 1.5 ppm per year in the 1990s, but it has climbed to 2.3 ppm between 2016 and 2017.
- This was the sixth straight year-to-year increase above 2 ppm, scientists said.