1. Increase in observed net carbon dioxide uptake by land and oceans during the past 50 years
2. Links between atmospheric carbon dioxide, the land carbon reservoir and climate over the past millennium
3. Boden T.A. Andres R.J. Marland G. (2017) Global Regional and National Fossil-Fuel CO 2 Emissions ( http://cdiac.ornl.gov/trends/emis/overview_2014.html ) Carbon Dioxide Information Analysis Center Oak Ridge National Laboratory Department of Energy Tennessee
4. Dlugokencky E. Tans P. and Keeling R. (2018) Mauna Loa Globally Averaged Yearly CO 2 ppm Earth Science Research Laboratory National Oceanic and Atmospheric Administration Scripps Institution of Oceanography a. http://www.esrl.noaa.gov/gmd/ccgg/trends/ ftp://aftp.cmdl.noaa.gov/products/trends/co2/co2_annmean_gl.txt
5. Economic value of improved quantification in global sources and sinks of carbon dioxide