How to misinterpret photosynthesis measurements and develop incorrect ecosystem models

At recent EGU General Assembly in Wien, I saw an interesting presentation by Professor Ian Colin Prentice (GS) entitled: How to misinterpret photosynthesis measurements and develop incorrect ecosystem models. I believe I already cited some of his papers (in our Precise proposal and “Can we trust Climate models?”), however, I did not faced his thinking directly. I would lie if I said that I understood his point. I am far too ignorant of the Carbon cycle and the way to measure it to understand. However, I accept the challenge to to start somewhere, because understanding the carbon cycle helps certainly to understand evapotranspiration. 

Please find below some relevant picture of his slides and, just after the paper(s) he cited. Probably reading those papers can be a starting point to understand.

I. C. Prentice, X. Liang, B. E. Medlyn , and Y.-P. Wang, Reliable, robust and realistic: the three R’s of next-generation land-surface modelling, ACP, 2015 

Hoffman, F. M., J. T. Randerson, V. K. Arora, Q. Bao, P. Cadule, D. Ji, C. D. Jones, M. Kawamiya, S. Khatiwala, K. Lindsay, A. Obata, E. Shevliakova, K. D. Six, J. F. Tjiputra, E. M. Volodin, and T. Wu (2014), Causes and implications of persistent atmospheric carbon dioxide biases in Earth System Models, J. Geophys. Res. Biogeosci., 119, 141–162, doi:10.1002/2013JG002381.

H. D. Graven, R. F. Keeling, S. C. Pipe, P. K. Patra, B. B. Stephens, S. C. Wofsy, L. R. Welp, C. Sweeney, P. P. Tans, J. J. Kelley, B. C. Daube, E. A. Kort, G. W. Santoni, J. D. Bent Enhanced Seasonal Exchange of CO2 by Northern Ecosystems Since 1960, Science 2013

Thomas, R. T., et al. (2016), Increased light-use efficiency in northern terrestrial ecosystems indicated by CO2 and greening observations, Geophys. Res. Lett., 43, 11,339–11,349, doi:10.1002/2016GL070710.

Wenzel, S., P. M. Cox, V. Eyring, andP. Friedlingstein (2014), Emergent constraints on climate-carbon cycle feedbacks in the CMIP5 Earth system models, J. Geophys. Res. Biogeosci., 119,794–807, doi:10.1002/2013JG002591 

Ainsworth EA1, Long SP, What have we learned from 15 years of free-air CO2 enrichment (FACE)? A meta-analytic review of the responses of photosynthesis, canopy properties and plant production to rising CO2., New Phytol. 2005 Feb;165(2):351-71.

Ning Dong, Iain Colin Prentice, Bradley J. Evans , Stefan Caddy-Retalic, Andrew J. Lowe, and Ian J. Wright, Leaf nitrogen from first principles: field evidence for adaptive variation with climate, Biogeosciences, 14, 481–495, 2017 doi:10.5194/bg-14-481-2017 

Zaehle, S., Medlyn, B. E., De Kauwe, M. G., Walker, A. P., Dietze, M. C., Hickler, T., Luo, Y., Wang, Y.-P., El-Masri, B., Thornton, P., Jain, A., Wang, S., Warlind, D., Weng, E., Parton, W., Iversen, C. M., Gallet-Budynek, A., McCarthy, H., Finzi, A., Hanson, P. J., Prentice, I. C., Oren, R. and Norby, R. J. (2014), Evaluation of 11 terrestrial carbon–nitrogen cycle models against observations from two temperate Free-Air CO2 Enrichment studies. New Phytol, 202: 803–822. doi:10.1111/nph.12697 

César Terrer, Sara Vicca,Bruce A. Hungate,Richard P. Phillips,I. Colin Prentice, Mycorrhizal association as a primary control of the CO2 fertilization effect, Science 2016