The level of carbon dioxide in the atmosphere July 22 measured 400.82 at the Mauna Loa Observatory in Hawaii, where annual, monthly, weekly, and daily records are kept. That compares with a measurement of 398.40 on that date last year.

An increase of 2 ppm seems to be the average incremental increase for weekly and monthly measurements when the figures are compared week to week or month to month for 2013 and 2014. That seems to be holding true for 2014/2015 as well.

Information is taken from web page of CO2Now.org, Mauna Loa CO2 Board, Scripps Institution of Oceanography. More information at https://scripps.ucsd.edu/programs/keelingcurve