by Antero Ollila, April 16 in WUWT
COP21 does not define the scientific basis of the agreement for the warming effects of the anthropogenic emissions, but it refers to a scenario. This scenario has not been defined in the COP21, but it can be found. The scientific resource of United Nations as well as of the COP21 is IPCC. The exact specification of IPCC is (Summary for Policymakers. In: Climate Change 2014. Mitigation of Climate Change”): “Baseline scenarios, those without additional mitigation, result in global mean surface temperature increases in 2100 from 3.7 °C to 4.8 °C compared to pre-industrial levels (range based on median climate response; the range is 2.5 °C to 7.8 °C when including climate uncertainty)”. Even though IPCC refers to multiple scenarios in the text above, the surface temperature increase to the average value of 4.25 ⁰C means one scenario only.