We have nearly reached 400 part per million.

The most recent monthly average of atmospheric carbon dioxide measured at Mauna Loa Hawaii in March 2014 was 399.65 ppm, compared with 397.31 ppm in March 2013. Humanity has nearly done it. BY the end of May the measurement will exceed 400 part per million, I have no doubt. We live, as the Chinese Curse would have it, in interesting times.