Carbon dioxide just hit its annual minimum and failed to dip below 400 ppm. We're unlikely to see a month below that level in our lifetimes.
In the centuries to come, history books will likely look back on September 2016 as a major milestone for the world’s climate. At a time when atmospheric carbon dioxide is usually at its minimum, the monthly value failed to drop below 400 parts per million.
That all but ensures that 2016 will be the year that carbon dioxide officially passed the symbolic 400 ppm mark, never to return below it in our lifetimes, according to scientists.
Via Marc Kneepkens