Please explain this, it's not making sense to me. By the contribution are you talking about the temp change?, or the change in the derivative deltaT/concentration with an increase in concentration?
If you'd quote a source that would be great...considering that this can almost be treated as a colligative property in the atmosphere and i have trouble believing that the derivative would approach zero at such a low concentration. Especially because there are huge differences in the absorption between 70% concentration by moles and 80% concentration by moles in CO2....which is way beyond anything in the atmosphere by a factor of millions.
Our modeling results show that nonlinear patterns were parabolic, asymptotic, and threshold-like in response to temperature, CO2, and precipitation anomalies, respectively, for NPP, NEE, and R(h).
1: Ecol Appl. 2008 Mar;18(2):453-66.Links Modeling patterns of nonlinearity in ecosystem responses to temperature, CO2, and precipitation changes. Zhou X, Weng E, Luo Y. Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma 73019, USA. zxuhui14@ou.edu
That took maybe 45 seconds on google.