Ed Berry, physicist and climate scientist: The scientific basis for the effect of human carbon dioxide on atmospheric carbon dioxide rests upon correctly calculating the human carbon cycle. This paper uses the United Nations Intergovernmental Panel on Climate Change (IPCC) carbon-cycle data and allows IPCC’s assumption that the CO2 level in 1750 was 280 ppm. Human emissions through 2019 have added only 31 ppm to atmospheric CO2 while nature has added 100 ppm. If human emissions were stopped in 2020, then by 2100 only 8 ppm of human CO2 would remain in the atmosphere. Siimon Aegerter, Eric Jelinski and Douglas Lightfoot offer comments from different perspectives.