A Milestone We Do Not Want – CO2 Concentration Exceeds 400 ppm
The remote mountaintop Mauna Loa Observatory (MLO) in Hawaii is an ideal location for monitoring the amount of CO2 in the atmosphere. For 24 hours on May 9 the CO2 concentration in the atmosphere atop exceeded 400 parts per million, or 0.04 pct. That is the highest CO2 level for more than two million years, it is the highest concentration in human history, and is a historically rapid increase of about 120 ppm since before the industrial revolution began in 1750. Passing 400 ppm is also an indication that the current efforts to curb CO2 emissions are inadequate, and we are on course for dramatic changes in the Earth’s climate. (more…)












