The goal of the Paris Conference is “to achieve a new international agreement on the climate, applicable to all countries, with the aim of keeping global warming below 2°C.”(21)
According to existing climate models, the attainment of this objective depends on substantially modifying the composition of the energy used around the world. The International Energy Agency estimates that in 2012, oil, coal, and natural gas represented nearly 82% of primary energy produced.(22) The global economy will need to have a negative carbon balance by the year 2100 if we want to achieve the 2°C goal, which means that more CO2 will need to be absorbed by carbon sinks (like the oceans), and removed from the atmosphere using various technologies, than the amount of CO2 that is emitted.
According to the IPCC, the concentration of GHGs in the atmosphere will need to stabilize between 430 and 480 parts per million of CO2 equivalent by the year 2100.(23) Excluding the other GHGs, this means around 400 parts per million of CO2.(24) In August 2015, the atmospheric concentration of CO2 was already close to this limit, at 396.86 parts per million.(25) Figure 1-8 shows the progression of the world’s atmospheric CO2 since 1980, as compiled by the Earth System Research Laboratory.
Global atmospheric concentration of CO2, 1980-2014
Source: Earth System Research Laboratory, Trends in Atmospheric Carbon Dioxide, Globally averaged marine surface annual mean data, October 5, 2015.
22. International Energy Agency, Key World Statistics 2014, 2014, p. 6.
23. Ottmar Edenhofer et al., “Summary for Policymakers,” in Ottmar Edenhofer et al. (eds.), Climate Change 2014: Mitigation of Climate Change, Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, IPCC, 2014, p. 13.
24. Oceans at MIT, News, 400 ppm CO2? Add Other GHGs, and it’s Equivalent to 478 ppm, June 6, 2013.
25. Earth System Research Laboratory, Trends in Atmospheric Carbon Dioxide, Recent Global CO2, October 9, 2015.