This chapter addresses what has boiled down into two simultaneous action trajectories: mitigation of carbon emissions to save the commons combined with various adaptation schemes. A large amount of energy has been expended by the international community on the subject of global warming and climate change. As long as gross domestic product increases faster than carbon dioxide emissions, the emission intensity will decrease. The chapter illustrates the size of the problem in reducing emissions to avoid further climate change and related impact and provide an indication of the magnitude and difficulty of the mitigation alternatives. It discusses many actions required or possible to reduce emissions to the levels deemed safe by scientists or to mitigate the many negative effects of a changing climate. The chapter presents conclusions expressed by the many organizations listed in Appendix A, "The Scientific Community Positions on Climate Change and Global Warming."