Istvan Marko (1956 – 2017) was a professor and researcher in organic chemistry at the Université catholique de Louvain, Belgium. CO2 is not, and has never been, a poison. Each of our exhalations, each of our breaths, emits an astronomical quantity of CO2 proportionate to that in the atmosphere (some >40,000 ppm); and it is very clear that the air we expire does not kill anyone standing in front of us. What must be understood is that CO2 is the elementary food of plants. Without CO2 there would be no plants, and without plants there would be no oxygen and therefore no humans. The equation is as simple as that. Our relentless crusade to reduce CO2 could be more harmful to nature as plants are not the only organisms to base their nutrition on CO2
