Note from Ralph Keeling as Keeling Curve reaches its annual low point: https://t.co/Vp1uYABCB3— Keeling_Curve (@Keeling_curve) 2016年9月23日
The Keeling Curve Note on Reaching the Annual Low Point September 23,2016 Rob Monroe
Is it possible that October 2016 will yield a lower monthly value than September and dip below 400 ppm? Almost impossible. Over the past two decades, there were four years (2002, 2008, 2009, and 2012) in which the monthly value for October was LOWER than September. But in those years, the decrease from September to October was at most 0.45 ppm – which would not seem to be enough to push October values below 400 ppm this year. The monthly value for October will therefore almost certainly also stay above 400 ppm and probably will be higher than 401 ppm.