"Man-made climate change may have began in the last two hundred years, but humankind has witnessed many eras of climate instability. The results have not always been pretty: once-mighty civilizations felled by pestilence and glacial melt and drought. But we have one powerful advantage as we face our current crisis: history. The study of ancient climates has advanced tremendously in the past ten years, to the point where we can now reconstruct seasonal...

Over the past fifteen thousand years the Earth has witnessed dramatic changes in sea level. The last Ice Age, when coastlines were more than 700 feet below modern levels, saw rapid global warming, and over the following ten millennia, the oceans climbed in fits and starts. These changes had little impact on the humans of the day, because the Earth's population was then so small, and those few people were more mobile than today's static populations....