Grapevine Yields in the Port Wine Region of Portugal
Santos, J.A., Malheiro, A.C., Karremann, M.K. and Pinto, J.G. 2011. Statistical modeling of grapevine yield in the Port Wine region under present and future climate conditions. International Journal of Biometeorology 55: 119-131.
In conducting their research, Santos et al. developed a statistical grapevine yield model that uses as predictors only monthly mean temperatures and monthly precipitation totals, and they demonstrated that it explains over 50% of the total variance in the grapevine yield time series over recent decades. Then, based on ensemble climate simulations under the IPCC's A1B emissions scenario, they used the model to project a slight upward trend in grapevine yield until the 2050s, which was followed by "a much steeper and continuous increase until the 2090s."
"Overall," in the words of the five researchers, "yields are expected to increase about 800 kg/ha until the end of the twenty-first century," which compared to the long-term mean of 3,104 kg/ha represents an increase of nearly 26%. In addition, they remind us that the projected rise in CO2 concentration can also directly produce an increase in net photosynthesis, biomass and grapevine yield, citing the work of Bindi et al. (2001) and Moutinho-Pereira et al. (2009), the former of which obtained a mean yield increase of 42% over two growing seasons in response to a 187-ppm increase in the air's CO2 concentration, and the latter of which obtained a mean yield increase of 42% over three growing seasons in response to only a 135-ppm increase in the air's CO2 concentration. And they say that the results of this sizable aerial fertilization effect of atmospheric CO2 enrichment can be added to their yield increase estimation, which is based solely on projected effects of climate change.
In light of these several findings, and what climate alarmists typically predict for earth's climate in response to anticipated changes in the air's CO2 content, we can almost hear the world's wine aficionados happily shouting Let the good times roll!
Bindi, M., Fibbi, L. and Miglietta, F. 2001. Free Air CO2 Enrichment (FACE) of grapevine (Vitis vinifera L.): Growth and quality of grape and wine in response to elevated CO2 concentrations. European Journal of Agronomy 14: 145-155.
Moutinho-Pereira, J., Goncalves, B., Bacelar, E., Cunha, J.B., Coutinho, J. and Correia, C.M. 2009. Effects of elevated CO2 on grapevine (Vitis vinifera L.): Physiological and yield attributes. Vitis 48: 159-165.