Carbon dioxide in atmosphere hits new record high as scientists call for 'every effort to slash carbon pollution'

Observations have been taken at the Mauna Loa since 1958. (Supplied: NOAA)

Scientists say we need to make "every effort" to combat dangerous climate change as the concentration of carbon dioxide in the atmosphere hits a record high.

Measurements from the Mauna Loa Observatory on Hawaii's Big Island averaged 424 parts per million (ppm) in May 2023, up 3 ppm on last year's May average, according to National Oceanic and Atmospheric Administration (NOAA) data.