Friday, December 19, 2008

Rural Economies, Methane, and the Little Ice Age.

Two stories on climate change graced the news today. One, perhaps more anthropology than physics, linked the conquests of Pizarro, Coronado, and other 15th and 16th-century New World "explorers" with the Little Ice Age. The other announced the not-too-cheerful news that methane is leaking from the Arctic sea floor in increasing amounts.

In these seemingly disparate tales there's a message for us. (Of course there is. There are messages in most things, everywhere if we take the time to look and think, no?)

First, the Conquistadors. We know that it was the diseases Europeans brought to the New World, as much as their new weapons technology and "Give-us-the-gold NOW" plunder that decimated Native populations. War by virus, as pointed out nicely in Jared Diamond's Guns Germs and Steel, is nothing new, but it was a major factor in de-populating the Americas, especially the lush landscape of central and South America.

Stanford University geologists Richard Nevle and Dennis Bird used charcoal from lake-bed sediments to document forest fires over the past 5,000 years. Presumably, the work of clearing forests for agriculture then was similar to today. Forest clearing by immolation. Fires lit by humans opened the land for crops. And the Incas, Mayans, and others, with large and growing populations, needed lots of crops. Its estimated that 100 million people or more inhabited the Americas in 1492, with the majority in Central and South America.

At least they did until European viruses wiped out more than 90 percent of native populations, with the greatest impact in MesoAmerica between 1500 and 1700.

That coincides with the "Little Ice Age", time of extraordinary ice and snow in Europe, hard times and scarce food.

Nevle and Bird link the depopulation of MesoAmerica to brutal 16th and 17th century European winters. (Fitting, if un-intentioned revenge). With fewer Native Americans to keep cropland open, and less need for crops, forests returned with a vengeance. Forests sequester carbon. And that additional carbon, sucked out of the atmosphere, combined with other factors that included increased sunspots, sent the global climate into an icy tail-spin. Only with the development of the industrial revolution did carbon dioxide return to the atmosphere and turn off the air conditioning.

And now, of course, we are back to doing the rainforest immolation thing, adding still more carbon, and decreasing the carbon up-take and sequestration capacity of tropical forests.

That brings us to the ominous news that methane--a far more "effective" greenhouse gas than carbon dioxide-- is beginning to leak into the atmosphere from the Arctic sea floor. The last time this happened, 55.1 million years ago, is known as the "Paleocene-Eocene Thermal Maximum," a time of an extraordinary spike in global temperatures driven first by bursts of methane from the sea floor of the northern oceans (and ultimately by volcanic CO2 added later).

This is not your normal methane seep. "The concentrations of methane were the highest ever meassured in the summertime in the Arctic," according to Igor Semiletov of the International Arctic Research Center. "We found methane bubble clouds above the gas-charged sediment and above chimneys going through the sediment," he noted.

To me, this is like that relatively slow -but-ominous leak you get around the nail in the tire. Drive a little farther at freeway speed and there's a blowout--with potentially disastrous consequences. My Toyota pickup has a nice safety feature--a little light that tells you when air pressure is low--or imperceptibly lower-- in a tire. The tires may look just fine. But the little light tells you there's a problem. This summer the little light came on somewhere in the gorge between Portland and Hood River. I stopped. The tires all looked fine. But, being a chicken, I paused in Hood River to get the tires checked out. The left rear had a three-inch-long nail embedded in it--a tire itching for trouble.

That methane leak in the Arctic, increasing in intensity, means it's time for us to pull over and change the tire. Or at least take it into Les Schwab for a fix. Before there's a blow-out.

But how do we do this? We can't stick a silicone plug in the Arctic Ocean.

Well, hark back to the cause of the Little Ice Age. The regrowth of forests. Carbon sequestration the old-fashioned way. This method--uptake by plants--is SO old-fashioned that it worked nicely in the Pennsylvanian, 320 million years ago to trigger Late Carboniferous Ice Ages. And it's partly responsible for ending the tropical globe and bringing ice to the Antarctic 34 million years ago, as vast planktonic blooms sucked carbon from the atmosphere and stowed in in the sea floor.

Suppose, just suppose, we restored forests. Even forests in the Northwest, even Westside Forests. Suppose we made restoring ecological health to these lands an economic priority. Suppose there were tax incentives not for just using the land for agriculture, but for how much carbon you could store. Suppose a vigorously growing tree was a valuable as a tree taken to the mill. Suppose the health of a forest floor or a grassland--both of which can sequester huge amounts of carbon--were as valuable as the livestock grazed there. OR more valuable.

Plenty of smart people will argue that ecosystem carbon storage is unreliable, not easy to measure and quantify, and is not "permanent". But what we need now is a tourniquet not cosmetic surgery. We need NOW, not permanent. We need to buy time until GM commits to make the Volt and we all buy one.

And anything will help. Forest and grassland-based carbon will be sequestered for a century or more. (Longer, presumably, than the Volt will last...) And evidently, forest growth turned the climate around in less than a century once before. So why not try this now?

Rural economies are in pain. In fact, more than pain. Destitution is a better word. Surely there is a way to support rural economies, eastside or westside, while moving with them towards a greener economy and cooler planet.


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