The book one of the founders of (German) Environmental and Climate Economics Prof. Dr. Lutz Wicke and the science journalist Dr. Markus Schulte von Drach show, why a 2°max-Paris Protocol as a follow-up Kyoto Protocol must be reached by 13 December 2015 and how this can be achieved.The basic article of Prof. Hans-Joachim (John) Schellnhuber and Dr. Daniel Klingenfeld show, why a very realistic 4°C warmer world by 2100 must be avoided in any case. One of the most important climate scientists of the world and a Harvard M.Sc. show very intensively how important it will be for mankind all over the world to avoid this most realistic warming of our planet - without any overstatement. Their report is based on PIK-Report for the World Bank.