03.02.13 9:45 AM ET

The Year Without Summer and Climate Change Today

When a massive volcano exploded in 1816, it plunged temperatures around the world. Mark Hertsgaard on the eerie parallels between this catastrophe and climate change in our own time.
The terms “global warming” and “climate change” never once appear in this book, but in relating the history of a literally earth-shaking event that occurred 200 years ago, the authors of The Year Without Summer have described a past that resembles our present in ways so uncanny, so numerous and fundamental, that the reader can only hope that Marx’s dictum—history happens twice, the first time as tragedy, the second as farce—will turn out to be wrong this time around.
The earth-shaking event in question? Not a military battle, not the overthrow of a government, the invention of a revolutionary technology, or any of the other human-centric themes that preoccupy most history books. No, this event’s protagonists were natural forces: a volcano whose eruption was the most powerful in recorded history, and the many changes that the volcano’s smoke and ash triggered on this planet.
The volcano, named Tambora and located on the island of Java in what is now Indonesia, exploded on April 5, 1816. As superheated liquid rock and gas gushed down the mountainside, an estimated 12,000 local people perished within 24 hours. 
But a far greater, and distant, death toll was yet to come. As the eruption’s detritus rose into the sky, it cohered into an aerosol cloud the size of Australia. Winds then blew this cloud westward across the continents, over Asia, Europe, and the Americas. 
Invisibly small, the droplets of sulfuric acid that formed this cloud were too light to fall to earth through gravity’s pull yet had enough mass to reflect some of the sun’s incoming rays back to space. The result was a dramatic shift in global temperatures. Before the year was out, weather on much of the planet had turned strange, nasty, brutal, and, above all, extremely cold.
Cold? Come again? Doesn’t that repudiate any linkage to global warming? On the contrary: it highlights the first parallel between the Tambora eruption and our own day’s experience with climate change, including a long-running misreading of what is actually taking place in the physical world we inhabit.

The Year Without Summer: 1816 and the Volcano that Darkened the World and Changed History By William K. Klingaman and Nicholas P. Klingaman 352 pages. St. Martin’s Press. $27.99.

The concept of man-made global warming was decisively put on the public agenda 25 years ago this June, when NASA scientist James Hansen testified to the U.S. Senate that an increase in greenhouse-gas emissions, begun by the extensive burning of fossil fuel during the 18th century Industrial Revolution, had significantly raised average global temperatures. After The New York Times reported Hansen’s testimony on the front page, “global warming” became a common phrase the world over. Even conservative politicians such as British Prime Minister Margaret Thatcher and President George H. W. Bush urged action, with Bush pledging to “counter the greenhouse effect with the White House effect.”
But behind the scenes, fossil-fuel companies were mobilizing to defuse this threat. They invested millions of dollars in a disinformation campaign that aimed to “reposition global warming as theory rather than fact,” according to an internal strategy memo. Attacking the science was key, which is where volcanic eruptions enter the story.
In 1991, a volcano in the Philippines named Pinatubo erupted. Like Tambora, Pinatubo unleashed an aerosol cloud that blocked some of the sun’s rays from entering the atmosphere, thereby lowering global temperatures. It turned out to be a very convenient development for deniers of climate change, for they could then point to an apparent flattening of global temperatures in the early 1990s to discount Hansen’s assertion that man-made global warming had begun.
Of course, scientists explained that Pinatubo’s aerosol cloud was merely masking the underlying warming trend temporarily. And sure enough, the trend reappeared in the mid-1990s, after Pinatubo’s cloud had dispersed. By then, however, the disinformation campaign had planted enough doubt that denial of climate change was established as a valid point of view in the U.S., especially in Washington, D.C., where it continues to thwart government action to this day.
Parallel No. 2: One of the deniers’ favorite talking points has been that even if the “alarmists” are right and greenhouse-gas emissions raise global temperatures by a few degrees, so what? Well, tell that to the victims of Tambora’s weather-shifting eruption.The Year Without Summer describes in meticulous, sometimes heartbreaking detail how even a small change in average temperatures can profoundly affect the day-to-day weather that humans encounter.
From May through September of 1816, temperatures in New England were “only” 2 to 7 degrees Fahrenheit below normal. Nevertheless, that lower trend contained enough extreme individual events to devastate agriculture and send shock waves through political institutions and economic and social practices.
In New York’s Hudson River valley, a frost in mid-June—weeks past the usual last frost—left the crops of wheat, rye, and vegetables “almost entirely destroyed.” In Quebec, farmers who had routinely sheared sheep to prepare them for summer temperatures watched them shiver to death after a bitter snowstorm struck on June 6. In September, another abnormally timed frost ruined what was left of the impending harvest, “kill[ing] off virtually all the crops that remained north of Pennsylvania.”
In a third parallel between then and now, the farmers, consumers, and governments confronted by this punishing weather responded in much the same way that their modern counterparts have reacted. Just as Putin’s Russia halted grain exports after record heat and drought crashed yields in 2010, so in 1816 did governments in Canada, the Netherlands, and Germany prohibit exports of grain and potatoes. In 2007 and 2008, production shortfalls caused retail food prices to rise beyond the means of many poor and working-class people around the world.  In 1816, scarcities likewise led to punishing increases: wheat prices in Britain and France doubled; in Switzerland, they quadrupled. (Quality also declined. Thanks to the incessant cold and rain, “You could not eat the bread,” complained one peasant. “It stuck to the knife.”) And just as the skyrocketing prices of 2008 provoked social unrest in dozens of countries, nearly toppling governments, so did both the rural and urban hungry masses riot and protest in 1816. “Crimes multiply with wants,” noted a traveler in Switzerland, adding, “the prisons are full, and executions frequent.”
This was scientifically mistaken, just as modern deniers of climate change have been when blaming sunspots for the increased global temperatures they can no longer dispute. Exhibit A is Frederick Seitz, a former president of the U.S. National Academy of Sciences who, before leading the charge against climate science in the 1990s, took $45 million from the R.J. Reynolds Tobacco Co. to fund research that discredited the idea that smoking causes cancer. In a 2006 interview, Seitz showed me a graph that supposedly demonstrated a link between sunspots and shifting global temperature levels, saying, “That’s what scientists should be investigating.”The fourth parallel is either the most bizarre or darkly hilarious of all.  As the ghastly weather of 1816 persisted, observers naturally tried to divine the cause of their distress. The favored explanation among the learned was sunspots. Newspapers in both Europe and the U.S. cited the appearance, in April, of an unusually large spot on the surface of the sun as a likely cause of the disastrously frigid weather. 
Finally, for those unconvinced by science, there were in 1816—as there are again today—supernatural explanations. Priests in Paris and self-proclaimed prophets in New England urged followers to appeal to God for deliverance from the weather. How different is that from the prayer meetings Georgia Gov. Ervin Perdue held in 2007, and Texas Gov. Rick Perry convened in 2010, to ask the Almighty to halt the droughts plaguing their states?
It’s odd, and unfortunate, that The Year Without Summer itself draws none of these connections between how people and institutions 200 years ago reacted to Tambora’s aftermath and how our own society is confronting the threat of global climate change.  It’s hard to imagine that the authors, a pair of academics who happen to be father and son, are unaware of them. Perhaps they assume that readers will recognize the parallels on their own. Or perhaps the authors fear being accused of unscholarly editorializing. But with our civilization fast approaching a matchless catastrophe of our own making, such self-imposed restraint betrays both our children and a scholar’s public responsibility.  Surely a central purpose of studying the past is to avoid repeating its mistakes.