Rolling one-year average exceeds 400ppm

[BFraser]

It looks to me as though sometime around the first of October, 2015, the one-year rolling average of CO2 concentration exceeded 400.  Since each year is about 2ppm above the year before, the rolling average moves fairly steadily upwards and will not go below 400 again in the foreseeable future.

Looking at the weekly averages, I get October 4th.

Looking at the monthly averages, I get something like September 27th.

Does anyone have access to the raw data (as opposed to the weekly and monthly averages I used) and want to take a crack at calculating the actual date we crossed that particular threshhold?

[oren]

Best to post this in the Mauna Loa CO2 thread

[JKDMaineUSA]

I remember being taught in school (1960's) that the best kind of combustion was one that just released CO2 and water vapor only. That CO2 gas and water vapor were necessary for the cycle of life on the planet, therefore CO2 was not a pollutant  anymore than we would consider water a pollutant. Yes, you can have too much of a good thing.