Under a Green Sky, Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us about Our Future by Peter D. Ward published in 2007. Climate varies in regular cycles of varying lengths. We live now at the end of a time of stability that is relatively rare. Humanity has flourished in a long period of the stability of what we consider to be normal climate, but in fact is very rare. Adding carbon dioxide to the atmosphere as we are will accelerate change and return us to a climate that varies markedly. In the future, coastlines will be different, crops will suffer, and many millions will die from starvation and/or war. I recommend this book.