The level of atmospheric carbon dioxide observed at a government facility in Hawaii reached a new peak in May, scientists from National Atmospheric and Oceanic Administration (NOAA) and the University of California San Diego said Thursday.

Last month, that the concentration of carbon dioxide in the atmosphere recording at the at Mauna Loa observatory was as high as 417.1 parts per million (ppm).

According to a NOAA statement, this was the highest monthly carbon dioxide level ever recorded. It was 2.4 ppm higher than the 2019 peak of 414.7 ppm.

Carbon dioxide levels measure how much of the gas there is in the atmosphere. This is different from carbon dioxide emissions, which measure how much new carbon dioxide is released into the atmosphere.