Summary

Chapter 19, “A Brief History of Climate,” kicks off Section V, “Global Warming,” and contains just one subsection. It follows a two-page introduction to the topics that Muller covers in Section V. Muller says that global warming may be the most difficult issue a future president will face. The planet Earth as a whole is warmer than it has been anytime in the last 400 years. This is most likely caused by greenhouse gases as a result of burning fossil fuels, but Muller says that this theory still needs to be subjected to scrutiny to prove it can hold up.

“The Climate of the Past 14,000 Years,” looks at the changes in the overall temperature of the Earth on a global time scale. The best way to look at changes in the weather going back before many civilizations...