1. E.Dlugokencky and P.Tans , Trends in Atmospheric Carbon Dioxide , National Oceanic and Atmospheric Administration, Earth System Research Laboratory (NOAA/ESRL) , 2020 , https://www.esrl.noaa.gov/gmd/ccgg/trends/global.html , accessed October 25, 2021
2. Rates of change in natural and anthropogenic radiative forcing over the past 20,000 years
3. P.Ciais , C.Sabine , G.Bala , L.Bopp , V.Brovkin , J.Canadell , A.Chhabra , R.DeFries , J.Galloway , M.Heimann , C.Jones , C.Le Quéré , R. B.Myneni , S.Piao and P.Thornton , Carbon and Other Biogeochemical Cycles , in: Climate Change 2013: The Physical Science Basis, Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change , ed. T. F. Stocker , D. Qin , G.-K. Plattner , M. Tignor , S. K. Allen , J. Boschung , A. Nauels , Y. Xia , V. Bex and P. M. Midgley , Cambridge, United Kingdom , 2013