1. Trends in Atmospheric Carbon Dioxide. Global Monitoring Laboratory. http://www.esrl.noaa.gov/gmd/ ccgg/trends/.
2. Conners, D., Scientists calculate a new rate for global photosynthesis, EarthSky, 2011. https://earthsky.org/earth/scientists-calculate-a-new-rate-for-global-photosynthesis.
3. Joos, F. and Spahni, R., Proc. Natl. Acad. Sci. U. S. A., 2008, vol. 105, p. 1425.
4. Le Quere, C., Andrew, R.M., Friedlingstein, P., et al., Earth Syst. Sci. Data, 2018, vol. 10, p. 2141.
5. Hausfather, Z., Analysis: Fossil-fuel emissions in 2018 increasing at fastest rate for seven years, Carbon Brief 2018. http://www.carbonbrief.org/analysis-fossil-fuel-emissions-in-2018-increasing-at-fastest-rate-for-seven-years.