The concentration of carbon dioxide (CO2) in Earth's atmosphere has been steadily increasing since the inception of the Industrial Revolution. Believed to be due primarily to the burning of fossil fuels and the clearing of forests, this phenomenon has two potential consequences of global importance.
Many scientists believe that the CO2 increases projected for Earth's atmosphere by the middle of the next century will lead to a significant warming of the planet which could severely impact world agriculture and cause a melting of polar ice which would greatly raise sea-levels and lead to the flooding of coastal lowlands. Others, however, point to the demonstrable positive effects of elevated concentrations of atmospheric CO2 on plant productivity and wateruse efficiency, suggesting that more CO2 in the air will be beneficial to The Biosphere. Against this backlog of controversy, scientists of both persuasions have attempted the ‘first detection’ of either or both of these effects on a global scale.
With respect to the quest for a climatic ‘signal’, numerous studies conducted to date have come up emptyhanded; it is just not discernible from the natural variations inherent in the data. However, there does appear to be a manifestation of enhanced global photosynthetic activity in the yearly amplitude of atmospheric CO2 concentrations at a number of sites around the world; and the most logical explanation of that seems to be the CO2-induced enhancement of plant growth and development which has been demonstrated to occur in hundreds of laboratory and field experiments.