Global warming is contentious and difficult to measure, even among the majority of scientists who agree that it is taking place. Will temperatures rise by 2ºC or 8ºC over the next hundred years? Will sea levels rise by 2 or 30 feet? The only way that we can accurately answer questions like these is by looking into the distant past, for a comparison with the world long before the rise of mankind. We may currently believe that atmospheric shifts, like global warming, result from our impact on the planet, but the earth's atmosphere has been dramatically shifting since its creation. Drawing on evidence from fossil plants and animals, computer models of the atmosphere, and experimental studies, David Beerling reveals the crucial role that plants have played in determining atmospheric change--and hence the conditions on the planet we know today-- something that has often been overlooked amidst the preoccuputations with dinosaur bones and animal fossils. "Beerling uses evidence from the plant fossil record (mutant spores, tree stumps from the Artic and Antarctic, growth rings) to reconstruct past climates and to help explain mass extinctions. Too often this evidence has been disregarded, but Beerling gives it its due, and then some."--BioScience