Comment on Modelling the seasonal contribution of a CO2 fertilization effect of the terrestrial vegetation to the amplitude increase in atmospheric CO2 at Mauna Loa Observatory by G. H. Kohlmaier et al.

Kohlmaier et al. (1989) present a detailed analysis of the increasing amplitude of the atmosphere’s seasonal CO2 cycle at Mauna Lao, Hawaii, finding that the aerial fertilization effect of atmospheric CO2 enrichment on the terrestrial biota accounts for only about a quarter of the observed amplitude increase between 1958 and 1987.