Dear authors,

All referees have recommended publication of your manuscript, which is informative, a significative contribution and very well written. I consequently decide with great pleasure that the manuscript be published subject to very few technical revisions.

Please (line numbers refer to the authors response version of your manuscript):

- l87 write "to the precision and accuracy requirements of the CO2M mission.", because the original wording is a quite difficult to read;

- l347 delete the phrase "; here we focus on discussing Figure 1", as this is entirely clear from the context;

- l547 : write "can be reduced by improved gas spectroscopic measurements in the laboratory". Your wording "measurement of gas spectroscopy" does not make sense to me;

- l625 change "The" -> "the".