The Inevitable Climate Catastrophe
Should we invest today in preparing for extreme weather or face the consequences of inaction? The 17th century offers crucial lessons.
… So far, most attempts to predict the consequences of climate change look to the future by building on recent trends, but another methodology exists. We can look back to a past climate-induced catastrophe, using sources created by both humans (narrative and pictorial as well as archaeological) and nature (above all, annual ice-core and tree-ring data). In a 2012 article in The American Historical Review, Julia Adeney Thomas, an associate professor of history at the University of Notre Dame, reminded her colleagues that “climate change—or climate collapse—and all of its related global transformations” is “a world-altering force,” one “more devastating, and more definitive” than any other. She called for an “environmental turn” in the field, one that foregrounds climate as a protagonist in human affairs.
The evidence for major climate change in the 17th century is both copious and unambiguous. Consider the year 1675. In July, the Paris socialite Madame de Sévigné complained to her daughter, who lived close to the Mediterranean: “It is horribly cold: We have the fires lit, just like you, which is very remarkable.” She added: “We think the behavior of the sun and of the seasons has changed.”
Madame de Sévigné was correct on both scores: 1675 is one of the few years with an exceptionally cool summer on record, and the narrow tree rings from that time reveal unusually poor growth; both grape and grains ripened later than at any other time in the previous five centuries. As for the sun, much of the 17th century saw a remarkable aberration: an almost total absence of sunspots, those dark regions of intense magnetic activity on the solar surface surrounded by flares that make the sun shine with greater intensity. The development of telescopes after 1609 enabled observers to track the number of sunspots, but although astronomers around the world stared at the sun on more than 8,000 days between 1643 and 1715 (the duration of the reign of Louis XIV, popularly known as the Sun King), the grand total of sunspots they observed scarcely reached 100, fewer than appeared in even a single year of the 20th century.
Nevertheless, it took human stupidity to turn crisis into catastrophe. The meager French harvest of 1675 occurred just as the king raised new taxes to pay for his wars, with predictable results. Many people died of hunger, many more migrated in search of food, and in the west of France, many took part in the “red bonnets” revolts. Most striking were the signs of hardship written on the bodies of survivors. Government officials in France compiled data on each man who enlisted in the royal army, including his height; those born in 1675 stood on average just five feet tall, the shortest cohort of Frenchmen ever recorded.
The earth also experienced an unusually cold winter in 1620-1, when the Bosporus froze so hard that people could walk across the ice between Europe and Asia—a climatic anomaly. The summer of 1627 was the wettest recorded in Europe for 500 years, and 1628 was another “year without a summer,” with temperatures so low that in many areas food crops never ripened. From 1629 to 1632, northern India suffered a catastrophic drought, while much of Europe suffered excessive rains. In the Alps, unusually narrow tree rings reflect poor growing seasons throughout the 1640s, and glaciers advanced more than a mile. In the Northern Hemisphere, 1641 saw the third-coldest summer recorded over the past six centuries; 1641-2 was the coldest winter ever recorded in Scandinavia; and 1649-50 was the coldest winter on record in both northern and eastern China.
Climate change on this scale seems to have triggered an unusual concentration of extreme weather events. In France, the river Seine has experienced 62 recorded floods, 18 of which occurred in the 17th century. Grape harvests in western France between 1640 and 1643 began a full month later than usual, producing wine too bitter to drink, while grain prices surged as a result of poor cereal harvests. Unseasonable weather in England ruined the corn and hay each year from 1646 to 1651, with five more bad harvests from 1657 to 1661: 11 harvest failures within the space of 16 years. Such abnormal climatic conditions lasted from the 1620s until the 1690s, the longest as well as the most severe episode of global cooling recorded in the past 12,000 years.
Why did this happen? A spate of major volcanic eruptions, including 12 around the Pacific between 1638 and 1644 (apparently an all-time record), produced dust veils that cooled the earth’s atmosphere, reducing mean summer temperatures by about 2 degrees Celsius. To a skeptic, such a change seems insignificant. But since the difference between the hottest and the coldest temperatures recorded since the last ice age is no more than 6 degrees Celsius, a change of one-third of the historical maximum is dramatic. In the 17th century, those climatic changes coincided with both political instability and mass starvation.
That century witnessed more cases of state breakdown around the globe than did any previous or subsequent age. In the coldest decade, the 1640s, Ming China, the most populous state in the world, collapsed; the Polish-Lithuanian Commonwealth, the largest state in Europe, disintegrated; much of the Spanish monarchy seceded; and the entire Stuart monarchy rebelled—Scotland, Ireland, England, and its North American colonies. In addition, in 1648 alone, rebellions paralyzed both Russia (the largest state in the world) and France (the most populous state in Europe); while in Istanbul (Europe’s largest city), irate subjects strangled Sultan Ibrahim, and in London King Charles I went on trial for war crimes (the first head of state to do so).
Wars also became more frequent. Europe experienced only three years of complete peace during the entire 17th century; the Ottoman Empire enjoyed only 10 such years; and both the Chinese and Mughal empires fought campaigns almost continuously. Civil wars proliferated. For six decades, supporters of the Ming and Qing dynasties fought for control of China. The rebellions of large parts of the Stuart and the Spanish monarchies unleashed internal conflicts that lasted over two decades in the former and almost three in the latter. The Germanic states, with powerful foreign support, fought one another for 30 years. France endured a civil war that lasted five years; the Mughals suffered two wars of succession. Throughout the Northern Hemisphere, war became the norm for resolving both domestic and international problems.


