We continue to string hottest days, hottest months, hottest years. August was the warmest since 1880. This year, 2016, is on pace to be the hottest ever recorded. An all-time peak reading of 409.44 parts per million (ppm) of carbon dioxide in the atmosphere was measured at the Mauna Loa Observatory in Hawaii on April 9 of this year. Mauna Loa is where the Scripps Institution of Oceanography and the National Oceanographic and Atmospheric Administration have been taking atmospheric carbon dioxide measurements for decades. 


The level Oct. 3 was 401.01 ppm, up four points from a year ago. 


Scientists announced this week that the carbon dioxide content of the atmosphere is not expected to be lower than 400 ppm ever again (unless some unknown technological advance allows us to remove CO2 from the atmosphere, not something we expect). Even that would not reverse or halt change. We have built permanent change into the system at our present level of CO2.