A sense of apocalypse hangs low over Elizabeth Kolbert’s Field Notes From a Catastrophe and Tim Flannery’s The Weather Makers, two important new books on global warming. Flannery, the director of the South Australian Museum in Adelaide and an accomplished science writer, warns: “If humans pursue a business-as-usual course for the first half of this century, I believe the collapse of civilization due to climate change becomes inevitable.” Kolbert, a writer at The New Yorker (where I also work), quotes a despairing New York University professor of physics, Marty Hoffert: “We’re going to just burn everything up; we’re going to heat the atmosphere to the temperature it was in the Cretaceous, when there were crocodiles at the poles. And then everything will collapse.”
But in many ways, the most striking thing that emerges from reading these two books and indeed from contemplating the larger phenomenon of global warming is that the earth has often been warmer than it’s likely to become in the next century–and not just for brief periods of time but for long swatches of its history. The question therefore becomes less one of apocalyptic endings–the biological world will no doubt survive global warming in some perhaps significantly altered form–than a political one of trying to parse just what kinds of changes we’ll have to make to adjust to what promises to be a brave new world.
Flannery and Kolbert are clear on the fundamentals. Greenhouse gases including not just carbon dioxide but also methane and water vapor have always existed in the earth’s atmosphere in a delicate balance with climate. By allowing solar radiation to reach the earth’s surface but trapping some of it before it radiates back out again, these gases have played a significant role in stabilizing the climate within the temperature bands that have allowed human life to flourish and expand over the past 10,000 years. Flannery points out that this 10,000-year period has been one of unusual climate stability and that it essentially includes the entire history of human civilization. He refers to it as “the long summer” and argues that climate stability may have been an essential factor in allowing humans to develop as they have.
But since the industrial revolution, we have been pumping increasing amounts of carbon dioxide into the atmosphere. By the mid-twenty-first century the atmosphere is expected to contain close to twice the carbon dioxide it did in the pre-industrial eighteenth century. This buildup of carbon dioxide has caused a rapidly accelerating warming of the earth’s atmosphere. As Kolbert notes, “1990 was the warmest year on record until 1991, which was equally hot. Almost every subsequent year has been warmer still…1998 ranks as the hottest year since the instrumental temperature record began.” The early years of this millennium were the second, third and fourth hottest until the figures came in for 2005, which established yet another record. “The world is now warmer,” Kolbert observes, “than it has been at any point in the last two millennia, and, if current trends continue, by the end of the century it will likely be hotter than at any point in the last two million years.”