Six different studies in which the designated types of plants were exposed in experimental plots to elevated (≈567 ppm) or ambient (≈365 ppm) atmospheric CO₂ concentration for 5 years or longer. Shown are percent differences in plant biomass between elevated-CO₂ and ambient-CO₂ plots as a function of treatment year.

Bloom (2010) Global Climate Change: Convergence of Disciplines. Sinauer Associates.