Over the past 400,000 years, CO concentrations have shown several cycles of variation from about 180 parts per million during the deep glaciations of the Holocene and Pleistocene to 280 parts per million during the interglacial periods. Each part per million by volume of CO in the atmosphere contains approximately 2.13 gigatonnes of carbon. Currently CO constitutes about 0.041 % (equal to 410 ppm) by volume of the atmosphere, which corresponds to approximately 3200 gigatons of CO, which includes approximately 870 gigatons of carbon. The global mean CO concentration is currently rising at a rate of approximately 2 ppm / year and accelerating.
what percentage of the earth's atmosphere is carbon dioxide
about 0.041 % (equal to 410 ppm) by volume