Resolution according to CO2 measurements in ppm and the calculation of the annual mean (rounded up or down) from Global Monitoring Laboratory at Mauna Loa.

I will resolve to 529 if the market trades for more than a week at 529 (the upper end of the range) or to 480, if it trades for more than a week at 480 (the lower end of the range). I will then create a new market with a more appropriate range. 

Graphs of historic CO2 measurements at Mauna Loa are here:

https://gml.noaa.gov/ccgg/trends/mlo.html

The data for historic annual means are here:

https://gml.noaa.gov/webdata/ccgg/trends/co2/co2_annmean_mlo.txt