Paper Reviewed
van der Kooi, C.J., Reich, M., Low, M., De Kok, L.J. and Tausz, M. 2016. Growth and yield stimulation under elevated CO2 and drought: A meta-analysis on crops. Environmental and Experimental Botany 122: 150-157.

Focusing on prior CO2 enrichment studies of agricultural plants exposed to drought, van der Kooi et al. (2016) searched library archives for studies of this important subject and what they might reveal about it. More specifically, they say that for biomass, they extracted "62 different data entries (for both dry and well-watered conditions) from 41 different experimental studies on 30 crop species," while for yield, they extracted "19 data entries (for both dry and well-watered conditions) from 17 experimental studies on 8 crop species," the results of which studies were published in the scientific literature between 1979 and 2014. And what did they learn from this methodical exercise?

The five researchers report that when experiencing drought conditions, both C3 and C4 crops responded very similarly to atmospheric CO2 enrichment. And they thus concluded that "crops grown in areas with limited water availability will benefit from future elevated CO2, regardless of their metabolism," due to the fact, as they report, that "drought leads to stomatal limitation of photosynthesis in both C3 and C4 crops, which is alleviated [in both cases] when the plants are grown under elevated CO2."