CO2 and Plant Growth
Technical Rating:

This study by Dr. Sherwood Idso shows that the world's forests increase their rates of carbon sequestering by 2.8 times in response to a 300 ppm increase in the CO2 content in the air. After two years of growth in a controlled experiment, trees in an ambient plus 300 ppm CO2 enriched environment were 2.8 times larger than the trees without CO2 enrichment.
Technical Rating:

This abstract shows that elevated levels of atmospheric CO2 causes a long-term biomass increase of 130% for conifer trees and 49% for deciduous trees in studies not involving stress components. However, stimulation of photosynthesis by elevated CO2 in long-term studies was similar for conifers (62 %) and deciduous trees (53 %).
Technical Rating:

This study evaluated the water use efficiency of orange trees at Phoenix, Arizona in response to elevated atmospheric CO2. The trees increased their water-use efficiency by 80% in response to a 300 ppmv increase in CO2, which is identical to the long-term CO2-induced increase in the trees' production of wood and fruit biomass. This suggests there could be little to no change in total water-use as trees' productivity increases with the air's CO2 content .
Technical Rating:

Lawrence Solomon shows that increasing CO2 in the atmosphere has caused the Earth's biomass to significantly increase. The planet is the greenest it's been in decades, thanks to man-made CO2 emissions!