AdvertisementCarbon Dioxide, Which Drives Climate Change, Reaches Highest Level In 4 Million YearsJune 07, 2021Eric McDanielfacebookEmailThis 2019 photo provided by NOAA shows the Mauna Loa Atmospheric Baseline Observatory in Hawaii. Measurements taken at the station in May 2021 revealed the highest monthly average of atmospheric carbon dioxide in human history. (NOAA Global Monitoring Laboratory)