Early warning: Columbus Iselin, former director of the Woods Hole Oceanographic Institution (seen in background), examined how global warming could change ocean currents, which in turn could accelerate the warming trend.
Concerns about global warming and how to address it (see Q&A) have a long history. The First World Climate Conference was held in 1979, and the United Nations created the Intergovernmental Panel on Climate Change in 1988.
Yet even those steps came well after scientists had begun taking the issue seriously. One example can be found in the November 1960 issue of this magazine, in which science journalist Robert C. Cowen warned that “we are performing a carbon-dioxide experiment which may change our climate.”
To be precise, the carbon-dioxide experiment began with the industrial revolution, when men started burning fuels in unprecedented amounts. Since the beginning of that revolution they have produced something like 12 per cent of the total carbon dioxide already present in the air. The capacity of the oceans to absorb this gas is enormous, however. Most of the excess produced in the past century probably has been removed in this way. The next century will be different.
Cowen cited Columbus Iselin, an MIT professor and former director of the Woods Hole Oceanographic Institution, who theorized that higher temperatures resulting from increasing carbon dioxide emissions would eventually prevent polar regions from producing enough cold, dense water to drive the “thermodynamic flywheel” that sends tropical waters into northern latitudes. Stifling the flywheel, Iselin said, would limit the amount of carbon dioxide absorbed by the oceans, with unpredictable results.
If the ocean’s ability to soak up carbon dioxide is reduced, this would increase the greenhouse warming effect as more of that gas accumulated in the atmosphere. Thus there may be a climatic persistence effect due to the oceans which enhances warming after such a trend has started. Once the climate has warmed up to a certain point, the oceans would stop overturning. Because less carbon dioxide would be removed from the atmosphere, this in turn would accentuate the warming trend, which would tend to persist.
Cowen stressed the uncertainty of long-term climate predictions, a problem that still dogs scientists. He noted that most scientists believed just a slight drop in global temperatures could spur an ice age. British geophysicist George Simpson, meanwhile, speculated that slightly higher temperatures could bring on a new ice age by increasing the amount of moisture in the atmosphere, which could mean heavier snows and growing glaciers.
Given that Earth’s climate was so delicate, so variable, and constantly in flux, predictions were hard enough, wrote Cowen. Now humans, with their “carbon-dioxide-producing industry,” had thrown yet another factor into the mix. Maybe experts couldn’t predict the consequences, but they felt safe in saying the results could alter the world.
The influence of this new and geologically unique factor may be operating in any of several directions. It could be tending toward a new ice age or could just as likely be producing another great tropical epoch like that prevailing when coal and oil deposits were laid down. Perhaps its influence is more moderate than such extremes suggest. The interactions are so involved that experts do not yet know how to sort them out. One thing they are sure of—this influence is at work on a scale to dwarf all previous changes man has made.
Cowen, now 84 and living in Concord, Massachusetts, retired this year after 45 years as a staffer and 15 as a columnist for the Christian Science Monitor (he’s also a former member of TR’s editorial advisory board). He notes that the theory of global warming actually dates back to the 19th century and was gaining ground “around the fringes” of the scientific community by 1957. He first wrote about it for the Monitor in 1958, in an article that he suspects might be the first on the subject by any American reporter.
He says scientists are partly to blame for our slow response, because they’ve done a poor job of explaining why the average person should care about melting ice caps. They could have focused more on the effect that drought would have on food prices, for instance. But he says that even the most ardent deniers will come around in time: “Eventually they’ll be able to look out their windows and see the results themselves.”
Timothy Maher is TR ’s assistant managing editor.