“By mid November of 2015, atmospheric carbon dioxide levels as measured at the Mauna Loa Observatory had again risen above 400 parts per million. Over the past two weeks, these levels maintained. And even though we may see a few days during which CO2 levels drop below that key threshold during late November and, perhaps, early December, those days could well be the last.”  From: robertscribbler.com

GR:  What does 400 parts per million mean for the Earth?  From the article:  “Atmospheric CO2 levels remaining at 400 parts per million for any significant period will push the Earth climate to warm by between 2 and 3 degrees Celsius. It will push for sea levels to rise by at least 75 feet. In other words, a world at 400 parts per million is a world radically changed. A world that human beings have never seen before. And as a cautionary note, the total forcing from all greenhouse gasses currently emitted by humans is now in the range of 485 parts per million of CO2 equivalent. A level well beyond the current 400 parts per million threshold and one that likely equates to around 4 degrees Celsius worth of long term warming.”