The human-caused global warming problem is now the focus of intense international attention in many sectors of society. As we learn more about the science of the problem, the sense of controversy about the state of the science has actually increased, sharply so over the past decade. This essay highlights the fundamental aspects of the science underlying global warming. The vital roles of climate models and of climate data in sharpening scientific understanding are featured. Finally, the roles of controversy in the science and the sociology of this problem are addressed, and new insights are offered on the inevitability of future major conflicts and controversies as society begins to deal with the need to either reduce the use of fossil fuels considerably or adapt to substantial changes in Earth＇s climate.