Climate change's most deadly threat: drought

Spring is on its way back to northern latitudes. In many locales, it will arrive earlier than "normal," yielding, ostensibly, a longer growing season, a hotter summer, balmier autumn, and future winters will lack their ferocious post-Pleistocene bites.

While vineyards are being planned for northern England, millions of residents around desiccated Atlanta are praying for enough rain to flow through their taps.

Brian Fagan believes climate is not merely a backdrop to the ongoing drama of human civilization, but an important stage upon which world events turn.

As it turns out, the anecdotal evidence of climate change in this, the 21st century, shares much in common with a historical antecedent, the Medieval Warm Period, circa AD 800 to 1200, that radically shaped societies across the globe.

The Medieval Warm Period was a time when the capacity of agriculture rapidly expanded and enabled people to flourish in Europe. Yet elsewhere, extended lack of rainfall, or too much of it, brought famine, plagues, and wars.

This bout of global warming was followed by the Little Ice Age that lasted roughly from AD 1300 until the middle of the 19th century and cast Europe and North America back into a big chill. Since then, mean global temperature has been slowly and steadily rising, accompanied by huge leaps in agricultural output and skyrocketing human population.

Today, climate experts tell us that over the past two decades, temperature has registered an alarming unnatural spike and is expected to keep climbing.

Despite the well-established fact that Earth is heating up, skeptics still are trying to poke holes in the assertion that it is owed to humans pumping more CO2 into the atmosphere. Climate change is, and always has been cyclical, they say. Or maybe, some insist, it is God who has his hand on the thermostat.

In his new book, The Great Warming: Climate Change and the Rise and Fall of Civilizations, Fagan does not engage in secular or religious ponderances. An anthropologist and professor emeritus at the University of California, Santa Barbara, the British-born author sees harvest seasons and weather patterns of the past as providing vital prologue for a fast approaching, water-challenged future.

In recent years, a flood of books about global warming has been written for the lay audience. Among the most noteworthy: Tim Flannery's "The Weather Makers"; Elizabeth Kolbert's "Notes From A Catastrophe"; Eugene Linden's "The Winds of Change"; and Ross Gelbspan's "The Heat Is On."

Each scopes out its own piece of the climate puzzle, from tundra to tropics and atmosphere to ocean, using plain narratives to explain a phenomenon that, when left to scientific lexicon, can seem too complicated to grasp.

Fagan, author of the bestselling "The Little Ice Age," makes an original contribution in "The Great Warming" by summoning attention to what he calls "the silent elephant in the room": drought.

As polar icecaps melt and glaciers disappear, thus causing seas to rise, low-lying coastal areas may indeed be inundated, creating millions of environmental refugees. But it is the inland agricultural breadbasket regions that feed the world that stand to suffer the greatest upheaval if reliable precipitation patterns vanish.

Such a scenario is not speculative, Fagan insists; it's based upon not only sophisticated computer models, but also the precedent of what's already happened during episodes of climate change half a millennium ago – in the Arctic, Europe, China, the Southern Hemisphere, and in America's own backyard. By taking readers back to the Medieval Warm Period and Little Ice Age, Fagan argues that history "shows how drought can destabilize a society and lead to its collapse."

Amid disturbances to growing seasons, humans suffered mightily, though our ancestors proved their resilience by adjusting opportunistically to changes that manifested over generations. That's the good news.

But the difference between then and now is that climate is changing faster today and the corresponding effects of drought over the next century have implications for hundreds of millions, if not billions, of people, some living in the wealthiest of nations, who Fagan believes are unprepared to cope with severe water shortages.

"Droughts are expensive in human terms and also carry a high economic price," he writes. "The notorious Dust Bowl droughts of the 1934-40 over the Great Plains scarred an entire generation. Three and a half million people fled the land." Imagine the Dust Bowl lasting centuries with no end in sight.

Now imagine the superproduce fields of California's Central Valley and the fast-growing Southwest, with desert cities like Phoenix, Tucson, Las Vegas, El Paso, and greater Los Angeles-San Diego confronting depleted aquifers and dry aquaducts.

To his credit, Fagan resists the temptation – until his final chapter – to rant, calmly guiding readers to global venues, like the Mimbres in Chaco Canyon, the Mayan on the Yucatán Peninsula of Mexico, and the sophisticated Cambodians at Angkor Wat where humanity thrived in warming environs only to perish from droughts. (Fagan's analysis is reminiscent of that by Jared Diamond in "Guns, Germs & Steel" and "Collapse.")

Events once considered anomalies, such as the current drought gripping metro Atlanta, could be commonplace and the kind of social mayhem witnessed during the aftermath of hurricane Katrina widespread. Globally, he points to the millions upon millions of people in Asia who rely upon fresh water emanating from glaciers in the Himalaya that are now disappearing and desert areas of Africa where drought events are foretelling larger disasters.

The imperative for policymakers, he says, is a massive and unprecedented intervention on a global scale. Civilization depends on it.

"We're not good at planning for our great-grandchildren yet this is what is required of our generation and those who follow," he writes. "Drought and water are probably the overwhelmingly important issues for this and future centuries, times when we will have to become accustomed to making altruistic decisions that will benefit not necessarily ourselves but generations yet unborn. This requires political and social thinking of a kind that barely exists today."

"The Great Warming" is a riveting work that will take your breath away and leave you scrambling for a cool drink of water. The latter is a luxury to enjoy in the present, Fagan notes, because it may be in very short supply in the future.

• Todd Wilkinson is a freelance writer in Bozeman, Mont.