Washington Post: Scientists who measure and forecast the concentrations of greenhouse gases in the atmosphere said Monday that we may have passed a key turning point. Humans walking the Earth today will probably never live to see carbon dioxide concentrations in the atmosphere once again fall below a level of 400 parts per million (ppm), at least when measured at the iconic Mauna Loa Observatory in Hawaii, where the longest global record of Co2 has been compiled.
Our forecast supports the suggestion that the...