According to measurements from the National Oceanic and Atmospheric Administration (NOAA), CO2 levels peaked at 424 parts per million in May this year, an increase of 3.0ppm over the same period the year before.
The measurements were recorded at Mauna Loa Atmospheric Baseline Observatory, located on the Mauna Loa volcanic island in Hawaii. The station, which has been operating since 1958, was built there because it is 3,397 metres above sea level and located far from any continent. These factors ensure that air samples collected there represent a good average for the central Pacific. The contamination from local volcanic sources is sometimes detected at the observatory, then removed from background data.
The carbon dioxide data on Mauna Loa constitutes the longest record of direct measurements of CO2 in the atmosphere.
“Every year we see carbon dioxide levels in our atmosphere increase as a direct result of human activity,” said Rick Spinrad, the administrator...