Recent research regarding plant production in enriched CO2 environments demonstrate that as CO2 levels and temperatures rise, we can expect considerable increases in plant growth. Conversely, past research on plant growth in depleted CO2 environments, and a Google search reveals much on the topic, demonstrated much reduced plant growth. One such study grew beans in environments with CO2 levels of 196 and 383 ppm and at air temperatures of 25 and 35 degrees C. The results revealed a 73% increase in net photosynthesis and a 200% increase in biomass at the higher CO2 levels and warmer temperature.
This now has me wondering what impact lower CO2 levels have had on the ability of past generations of not only man, but animals, to feed themselves, not only to obtain optimum growth rates, but to multiply. Is the rapid increase in population levels related to improved food production due to warmer temperatures and increasing CO2 levels? I suspect that the prolific growth that resulted in large amounts of carbon being locked up as fossil fuels, which if not for man's intervention, would in the main remained locked up forever, actually depleted the atmosphere of sufficient CO2 to maintain optimum plant growth. In the natural order of things, if the demand for nutrients increases, and CO2 is a nutrient, the most essential nutrient of all, and the increased demand depletes existing availability and exceeds any natural replenishment, growth slows until replenishment again exceeds demand and growth levels improve. Given what research has found regarding growth in both depleted and enriched CO2 environments, it appears to me that the earth at present is not in a state of balance, but rather rebounding from a deleted unbalanced state. Perhaps if peoples precious water front real estate was ignored, there may be different conclusions being arrived at regarding what rising CO2 levels and warmer temperatures might mean for life on earth.
