As natural emissions of carbon dioxide are very much greater than those from human activities, surely the effect of man is insignificant?
The exchange of ‘man-made’ carbon dioxide between man-made emissions, atmosphere, ocean and land, is about 7 GtC/year (billion tons of carbon, in the form of carbon dioxide, per year), which also shows much larger natural exchanges between atmosphere and ocean (about 90 GtC/yr) and atmosphere and land (about 60 GtC/yr). However, these natural exchanges have been in balance for many thousands of years, leading to the pre-industrial concentration of CO2 remaining steady at about 280 ppm.
