Global warming, global everything

kw: book reviews, nonfiction, climate change, polemics

About 14,700 years ago the most recent Ice Age ended with a staged warming that totaled 18°C. Then a sudden cooling of about half this amount occurred, starting a period known as the Younger Dryas (named for an Alpine flower that became common at low elevations), about 12,900 years ago. This cooling lasted until 11,630 years ago (9620 BC), and ended with an abrupt warming by 10.5°C. Another half degree was all it took to bring on the Medieval Climatic Optimum, which lasted from 800-1300 AD. Gradual cooling by half a degree, then a sharp drop of another half, led to the Little Ice Age (1650-1880 AD). Warming by a degree led to the modern era (post-WW I), and another half degree of warming has occurred since.

I wonder whether the American Revolution would have been less successful, or even more so, had it not occurred during such a cold period. More to the point, if further climatic warming by another degree-and-a-half occurs, what will be the consequences? During the presidency of George Washington, New York and Boston experienced seasons that today are found in Halifax and Ottawa. The simple conclusion is that Halifax could be more like New York is today. Skipping down the coast a similar amount, New York might become more like Charleston, Charleston like Atlanta, and Atlanta like Miami.

My former home on the West coast, Anaheim, could become more like Mexico City (or at least Acapulco), San Francisco like Anaheim, and Seattle like San Francisco. Other parts of the globe can make similar interpolations, except those already within the Tropics, who are likely to experience weather unlike anything recorded historically.

This could happen in my lifetime: My father is still alive and vigorous, and is 25 years older than I. I had at least three great-grandparents who lived to be 88-92. What will life be like in 2030-2040? …for me??

But warming is only part of what is going on. Whether human generation of carbon dioxide is causing it or not, the climate is warming. But at least three other elements are causing global troubles, and their increase is of undoubted human origin. Fertilization is the culprit in two cases: Phosphorus from fertilizer runoff is being released into the oceans at FIVE times the natural rate, and fixed (oxidized) Nitrogen from both runoff and vaporization, plus auto exhaust, is DOUBLED. Then, burning and refining of fossil fuels releases Sulfur oxides into the atmosphere at THREE times the normal rate. Compare these with the Carbon Dioxide release: we add about ONE PERCENT to the natural carbon cycle.

All the facts above underlie Dianne Dumanoski's presentation in The End of the Long Summer: Why We Must Remake Our Civilization to Survive on a Volatile Earth. The ice age timing with which this post started just underscores the author's main point: We live in a time of unusual stability. Our ancestors didn't have it this good. Our descendants may not either.

Consider the evolution of hominid/hominin species since the line split off from a chimplike ancestor five million years ago (5Mya). Between 5Mya and 2Mya, during most of the Pliocene era, precursors of the ice ages occurred about every 40-70,000 years. They were less severe than the later Pleistocene ice ages, and in Africa in particular, led to a breakup of the continent-wide forest into broken forest/savanna landscape. Hominins such as Australopithecus became bipedal and walked upright into these open spaces, while the other apes stayed in the forests.

Starting just before 2Mya, the Pleistocene Ice Ages came around, each cold-warm cycle lasting about 100,000 years. The four most recent were the most severe, and have been named for type localities such as Wisconsin. Each of these latest four seems to coincide with a doubling in brain volume in the line that led to the genus Homo. Hominins, having embarked on a generalist/omnivorous life style, multiplied their reliance on culture, particularly its educational aspects, to rapidly adapt to rapidly changing climate: an Ice Age isn't just a square wave, in which a block of ice arrives, stays for 90,000 years, then vanishes. It is a series of abrupt pulses between merely awful cold and really bitter "here comes the glacier again!" chilling. Those groups of fire-using apes that were smartest and took best advantage of changing conditions prospered, and the most prosperous ones led to Homo sapiens.

Some time near the end of the most recent ice age, the last cousin species, the Neandertals, died out, and by the end of the Younger Dryas, the remarkably stable Holocene period began and continues today. This period began with the dawn of agriculture, which quickly spread and is the support for all but a few human groups.

Human population has grown about a thousandfold in 11.6 thousand years. Just the need to feed 6.6 billion of us has made us a geological force. But another factor, really an attitude, is Ms Dumanoski's second point: Both the developed and the developing world have embraced the paradigm of increasing economy as the greatest good. And by "increasing" they mean "per capita". Thus, while global population grows two percent yearly, today's leaders of nearly every political stripe expect growing prosperity to cause the global economy to grow at least twice that fast, typically about 5%. Five percent for 100 years means a factor of more than 130. Will the global economy in 2110 be 130 times the size of today's? Where will we get the resources?

Here the long view comes in handy. Consider that, entirely without our help, temperatures during the Pleistocene have been both 20 degrees cooler and 10 degrees warmer than they are today. Entirely without our help, sea level has fallen by as much as 100m, and risen by 50m, compared to today's levels. Volcanic eruptions larger than Tambora (which may have caused the Little Ice Age) could occur at any time, leading to a few years of acid rain, and perhaps decades of bitter cold again. Or a large melt of permafrost could release enough methane to warm the Arctic by 10°C in just a few years; it would take 20-30 years for that methane to oxidize to CO₂, and then the warming would back off to "only" 2°C.

Thus the third point is this: Earth has lots of tricks left up her sleeves. Civilization is like an organism that requires very, very stable conditions. Start to shake things up, and do so rapidly, and it could end. Just in my son's lifetime, "just in time" inventory practices have become so widespread that most manufacturing would end within a day or two of a supply disruption. So would food supplies. "Single sourcing" is the norm now, a further risk. These are just two of several warning flags the author raises.

We've had a 12-millennium Long Summer in which Mother Nature has been playing nice. The Little Ice Age was just a two-century "blip", a playful swat on the behind. If Mother Nature is in a conciliatory mood, another such swat might occur to prod us to revamp Civilization into a more robust model. Perhaps a swat with the other hand, say Greenland suddenly melts and Boston and New York and London and S.F. and Tokyo go half underwater (and most Micronesian islands vanish). And that is just attention-getting.

Finally, small stimuli can have large effects. Recall that we "only" increased the volume of carbon emissions by a percent. The Ozone hole scare of a decade ago was caused by chemicals we released that never rose to even one part per billion of the stratospheric gas. But high-altitude polar ice clouds conferred on each Chlorine atom the ability to catalyze the destruction of 10,000 Ozone molecules. Recent calculations show that Bromine is a thousand times as potent. Aren't we lucky that bromine costs a lot more than chlorine? Otherwise "freons" might have been BFC's instead of CFC's, and we'd all need SPF 50 sunscreen just to walk across the street. Of course, we'd also be having a hard time breathing, because oceanic algae would have died out by now. And although the scare has passed, the ozone hole now forms every year, and will do so for 30-50 years.

It is really a pity we don't have a spare planet to try stuff with. But we don't, and we've already started down the garden path with C, N, P, and S enrichment, plus Cl high in the sky. If we were to stop releasing them entirely TODAY, it would take decades for their effects to decrease significantly. You might say, we've already jumped off a cliff, and we're falling. We just don't know how long until we hit bottom, or how hard we'll hit. We just don't know.