CO2 Levels Reach and Maintain 400 PPM – A Dubious Milestone in Human History
The World Meteorological Organization reports that, for the first time in human history, atmospheric concentrations of carbon dioxide (CO2) eclipsed 400 parts-per-million (ppm) in the northern hemisphere for the entire month of April.CO2 concentration varies with the seasons, generally reaching their highest level early in the northern hemisphere’s spring before seasonal intake of CO2 from vegetation. The first recording of 400 ppm…
