Sobering science-based reminders. . - book review

The Little Ice Age: How Climate Made History, 1300-1850 by Brian M. Fagan. Basic Books, New York, 2001. ISBN 0465022723.

The Eternal Frontier: An Ecological History of North America and Its Peoples by Tim Flannery. Atlantic Monthly Press, New York, 2001. ISBN 0871137895.

Throughout human history, weather and weather changes have been a source of supernatural speculation. Extreme weather, beneficent or malign, has long been seen as a manifestation of the will of the Gods to reward or punish humankind. More recently, weather and climate have become sources of equally fantastic futurist doomsday scenarios as well. Look mote closely, however, and all this superstition should not be unexpected. It is surprising how little we know, empirically, about climate and human history. It might be said that angels lurk where scientists have yet to tread. The two books reviewed here both aim to remedy our ignorance. Both argue that climate is a product of lawful global processes that can be analyzed and understood and that man, while having distinct advantages over animals in being able to adapt to climate changes through technological means, is still ultimately prey to these forces. And both provide examinations of climate's relationship to civilization in the past that are compelling and, ultimately, unsettling.

Despite their similarities, these are two very different books. Fagan's is a detailed examination of "recent" history, a dramatic cooling then warming trend that took place during a five-to-six-hundred-year period lasting from 1300 to 1850 or so. Culling data from medieval and Enlightenment-era records in Western and Northern Europe, his goal is to show that the effects of climate change on human society can be concretely measured. He correlates the cooling documented from natural sources like tree rings and ice cores with human records of events like droughts, crop failures, and changes in seafaring routes. He then attempts to relate these climate-driven events to larger political and cultural changes.

Fagan argues, for example, that primitive French agricultural practices produced mass starvation when crops failed in the cold years and that this starvation was a contributing factor in the French Revolution. Thus, he reasons, climate change was a causal factor in one of history's most dramatic events. You don't have to accept this oddly indirect logic, however, to enjoy the book because there are so many other interesting concrete examples of climate impact.

I found the strange story of England's wineries to be the most striking. Once a major supplier of wine to Europe, the cold spell led to the complete collapse of viniculture in the British Isles. Only recently have grapes been re-established there again, as the world has gotten warmer.

The weakness of this book is that the many details, while intriguing, end up as a sort of a hodgepodge. Fagan relies on the sheer bulk of evidence to make his case. While many of his examples are insightful, others are not and this weakens his argument. The unevenness of the data aside, Fagan has pointed the way to re-examining many historical records for climate research purposes and has gathered much of them in this book for the first time.

Flannery's book takes a much broader time frame and geographical reference. He examines climate not over a few centuries but over millions of years--the last 20,000 or so in particular--and he is concerned exclusively with the North American continent. This is a very informative book, well written and thoughtfully presented. It starts with a review of the unique geological history that has made North America an "eternal frontier," constantly invaded throughout history by newcomers of all kinds from other continents. Flannery describes how North America's geography makes it unique in its extremes of weather: Deep winters and baking summers are a norm nowhere else on the planet. This same geography serves to amplify the impact of global heating and cooling trends, which have contributed to periodic extinctions on the continent.

When it comes to the climate's effects on man in the Americas, Flannery makes a strong case that the "mysteriously rapid" rise and fall of ancient pan-American societies, so breathlessly attributed to alien migrations or other silliness by New Agers, actually reflects the impact of climate changes combined with environmentally unsustainable farming and cultural practices. As this analysis suggests, his discussion of human interaction with the environment is unsentimental. He makes a strong case that the first human immigrants to North America, who did not farm and whose major artifacts are stone spearheads, Literally hunted most of the continent's large animals of all kinds into extinction, inflicting serious damage on the ecology of the continent that remains to this day.

Flannery tries to be upbeat, but his assessment of North America's future is disturbing. European colonization has only exacerbated the damage done to the continent's ecosystems. He believes that large animals must be reintroduced to restore "balance" to ecosystems. He also warns that North Americans are rapidly consuming the continent's fresh water and exhausting its soil. Global warming could well bring dramatic changes in heat and cold distribution in North America. with tropical and subtropical invaders from South America and elsewhere finding new homes in the North, and large areas of the interior continent being given over to desert scrub.