Plows, Plagues & Petroleum: A Review

William Ruddiman , one of the early paleoclimatologists —a climate scientist who studies climate in ages past– is the father of the hypothesis that bears his name:  that mankind began changing the climate long before the Industrial Revolution started burbling enormous amounts of CO2 into the air.  Ruddiman began to suspect it was far earlier when he noticed a strange, and strong,  anomaly in the regular cycle of methane increase and decrease he had been reading from the geological records during his academic career.

From extensive sampling and analysis of trace elements in the geologic record it was clear that methane in the atmosphere rose and fell in regular cycles, similar to the cyclical increase and decrease in ice coverage of the earth as first deduced by Milutin Milankovich, a Serbian mathematician, while held in prisoner of war camps in WW I.

The amount of heat the earth receives from the sun, as everybody knows, changes with the seasons.  As the earth makes its way around its elliptical orbit, the axis of tilt stays the same, in our era a tilt of 23.5 degrees.  When, moving around the sun, the axis is tilted towards the sun — more heat in that hemisphere; when it is tilted away — less heat.  Herein begins the interesting observations.

1) The axis stays “the same” during any particular orbit.  But in fact it doesn’t.  It varies over a cycle of 41,000 years.  The most extreme is 24.5 degrees, the least is 22.2.  We are, in our current years at 23.5.  At the greatest tilt more heat would be absorbed in the summer, than now, and less heat in the winters.

2) The axis also “wobbles” or precesses.  Like a top the axis slowly moves in a small circle even as it spins.  Thus Polaris is our North Star now.  When the pyramids were being built it was Alpha Draconis, or Thuban to the Egyptians. The complete cycle -from Polaris to Polaris- is 22,000 years.  The wobble of course changes the angle of the axis and thus the amount of earth surface area receiving heat in the summer.

3) The elliptical orbit of the earth also changes.  The eccentricity, as it is called, becomes almost zero — that is, a perfect circle — in a cycle of 100,000 years.  Needless to say, when the eccentricity is low more heat will be received on earth than at the ends of more elliptical orbits.

These three effects on the earth’s heat absorption have been dubbed the Milankovich Cycles. The driving question for him was the growth and retreat of ice-sheets, mostly in the north but also the south. He postulated that these cycles of orbital and axial change matched very well with many different periods of glaciation in the earth’s history.

In 1981 a meterologist named John Kutzbach had the break-through idea that the same orbital changes were connected to monsoonal cycles as well. Though we think of monsoons as almost a strictly south Asian phenomena, there have been repeated times in earth’s history when the southern Sahara and the Sahel, much further to the west have been grassy plains with large lakes and rivers, unlike the deserts they are today. Kutzbach postulated that the monsoon belt increased, and dropped further south, as solar heating increased. As heating decreased, due to the Milankovich cycles, the monsoons left Africa, and left it high and dry. When large areas grow seasonal vegetation, methane is released into the atmosphere as the vegetable matter decays. As it turns out, the methane rise and fall track the wetting and drying of Africa pretty precisely. More heat –> More Monsoons –> More Methane. The cycle from dry to wet and back to dry is about 22,000 years.

Ruddiman, conversant with all this, and having been a student of Kurtzbach, began to wonder late in his career, why the methane measurements from about 5,000 years ago started going up instead of continuing to fall as would be expected —  the earth continuing into the cooler part of its cycle?  The conclusion he came to, and called the Ruddiman Theory,  is that as Homo Sapiens spread across the earth following the last great ice age they not only began felling trees and doing slash and burn agriculture, releasing CO2 into the atmosphere while decreasing the size of the CO2 sinks, but especially in SE Asia they began flood irrigating and planting large stands of rice.  The seasonal post harvest remains, as they rotted, released great new amounts of methane into the air, reversing what would have been a downward trend of methane in the atmosphere, and as a result, helping to create the odd 8,000 year span of moderate human-scale climate we’ve enjoyed since about the beginning of the agricultural era.  Had it not been for this CO2 and methane forcing, the earth would likely be in another deep glacial age by now.

The book Plows, Plagues and Petroleum is Ruddimen’s 2005 attempt to bring together the various papers he had published, and strands of thought pursued in working out his theory.

It is not an uncontested theory, as he readily admits.  Others think there are simpler explanations than his for the evidence he cites.  He acknowledges their doubts and tells us why he thinks his ideas hold up.  For a very clear set of examples of how scientific argument works, always hewing to and interpreting real, mutually confirmed data, you couldn’t do better than to read Chapter 11, “Challenges and Responses.”   The competition between scientists is so sharp one wonders how a current popular (anti-science) meme ever took hold in certain circles — that scientists are captives of a herd-like mindset, unable to resist popular ideas or peer pressure.

A second hypothesis follows the first.  What, in the human record, might account for several dips in the CO2 record during its general upward trend?  Plagues?  Have there been severe enough decreases in human populations in the past 2500 years to result in less forest clearing, less slash and burn, less rice farming?   His research led him to say: the major CO2 dips in the ice-core records correlate more persuasively with population drops caused by major pandemics than do with times of war or famine.”

Petroleum, the third of his title nouns, needs no review here.  We are mostly familiar with what petroleum and coal have wrought.  Nevertheless, it is interesting to read it again through a careful scientist’s eyes.

In closing, Ruddiman tells us he has not had a dog in the current climate change fight until recently.  His expertise has been in climate change in past millennium.  He has had no funding from industry or environmental sources,  nor real interest in the highly politicized climate change assertions and counter assertions.  He does however –he says in an Epilogue– have an opinion.  The discussion, he thinks, has been wrenched  at both ends by alarmist predictions — to the detriment of science.  Further, while he has no doubt that climate change is happening, he does not think it is the greatest threat to the survival of mankind.  The shorter term issues of water and soil and fossil fuel depletion are likely to be much bigger problems, sooner.

Plows, Plagues and Plowshares isn’t a book everyone will appreciate or find their time well repaid.  For those who the current political and rhetorical attitudes have shaken up, and have an interest in the real science underlying the serious claims, this is a good, short, if academic book [Princeton University Press] to absorb, and let add to other sectors of your knowledge.

Available at Princeton Press or your local library!

Big Sur in Springtime

Big Sur in Springtime

Big Sur in Springtime

On Easter Sunday we hiked a few fingers of the great hand of God, the Santa Lucia mountains and the coast line of Big Sur. The Big Sur river itself, just 4 days before, had churned its muddy way over the bridge on Highway One, and half-buried several cars in a once green meadow. The raging fires of last summer had left lots of open earth. The later winter rains had saturated it and a nondescript shower on Tuesday had been the more than the muchness needed for one section up river, loosed it and down it came. By Saturday the earth movers and shovel handlers had been out and the road was open, the river clear and cold. No one had been injured.

The climb up to Buzzards’ Roost from the south end of the bridge is over an hour of not quite continuous switchbacks almost entirely through cool coastal redwood forests. Maidenhair and five-fingered fern, miners’ lettuce, the ubiquitous redwood sorrel with its three clover like heart-shaped leaves, some sprouting lovely white flowers spread wide along the trail. Big leaf maple, sycamore and alder try to out compete the redwoods, here and there succeeding. A solitary brown creeper makes its way steadily up a redwood trunk looking for lunch. Stellar jays scream to each other, yak at us. The egg-yolk yellow of a warbler captures our attention for a long as she’ll stay still — not long at all.

Coastal Redwood, Big Sur

Coastal Redwood, Big Sur

At the top of the climb, the shelter of the trees below, the final yards of the trail lined with blackberry brambles and manzanita, we stand in chaparral, sage and beautiful yellow deerweed, waist high, and see the broad expanse of the Pacific, the fog-belt cinched four miles off-shore. The wind is still cool though the heat is noticible. Beneath our feet is a tumble of magma, hard-cooked layers of sandstone that have been through the trenches of hell before being pushed to these heights. Distinct bands of yellows and ochres from river run-off millions of years ago are clearly visible — all in God’s own unmistakable signature.

Death Valley, April 2008

Death Valley in the morning, at least in early April, is cool. Enough for a second shirt or jacket. The sun rises up over the Amargosa range and slowly washes the Panamints free of the night, starting with the still snow peaked summits of Telescope Peak as white as the salt flats 11,000 feet below on the valley floor will be at noon. The stone in the Panamints is young, a few million years young and as the young will do, still moving west, pulling the valley floor with it. The far side, along the morning shadow of the Black Mountains, is pulled and stretched for millenia and drops, millimeter down. This morning Badwater is 282 feet and a smidgen below sea level . We can see it on a horizon of salt from where we are scouting for water out along the Westside Road. As the shadows gather eastward the Blacks seem to rise as they began to rise 20 to 10 millions of years ago, lifting what would become the Panamints on their backs until they slid, sliding for millions of years to the west, the west, opening a valley between the two ranges. As it deepened, they both, mother and child, shed themselves down into it. The salty, sandy, gravelly floor of the basin, so flat to our eyes now, actually continues down for thousands of feet before it finds bed-rock. Thousands of feet of mountain tops, backs, shoulders and hips washed like dirt down a driveway. The mountains we see are dwarves of their former selves.

I don’t know why most people go to the desert. I’m not sure why I do, again and again. Few go I think because they are true hermits, the Saints Simeon Stylites or Anthony the Great, Li Po or Han-Shan of religion or foundational longing. Most of those I run across in small hamlets perched on the edges of the Mojave or Death Valley are false hermits, saying they want to get away from it all but really content in the small slighting contact of these skeletal communities. Leave me alone, but not completely they seem to say. Though living more modestly than their urbanized kin they are not, by and large, true ascetics. Minimalists perhaps in aluminum house trailers that will never be trailed, a cactus or two let to colonize the sand and gravel that serves as a front yard, a stone walk across it, a television antenna gripped to a corner, even, these days, an internet connection. I don’t think as I see and talk with them they came for what I am finding.

For me it’s like this: You go into the desert dirty and you come out clean.

You go, the first times, with ideas of heat, of thirst, of salt, sand, dirt and rock. You might imagine a lizard gasping at noon, a vulture or two with longings for carrion. You look it up and read about Shorty Harris and borax mines, birds dropping dead from the shock of the super heated air. You might even read of wildflowers and think of bristles on an old man’s chin.

You go and you hit the high spots: Zabriskie Point, Golden Canyon, Badwater, the Mesquite Dunes. You stop at Furnace Creek and ask for a milkshake or the coldest beer in the universe. You might troll through the general store and drop a picture card through the slot to send a Death Valley postmark to a favorite child. And somewhere in those early hours, if you’re lucky, you realize you’ve stepped into another river of time, a river of huge silences and minor riffles of noise. You understand these are silences not just of sound but of sight.

Going to a desert is like going to many other wildernesses. But more.

We go to get away, to flee the clangor and the noise, the press of obligations, the unstoppable tick of things to be done. Sitting for an hour bay side, or trail walking Mt. Tamalpais will do these things for you. Hiking the Adirondacks, or paddling Lake Champlain, pulling yourself up wilderness trails in the Rockies, sailing on the Chesapeake will do these things. But as I noticed yesterday, the desert takes you away as all these do, and then takes you further. In the desert there are no trees rustling in the wind. There are no stays and shrouds slapping on masts. There are no trails lacing a hillside, showing recent decades of humankind. There are no flights of birds. All this visual “noise” is missing.

Nothing is brought to you. Nothing holds you in familiar places and so, if you don’t flee, anxious and unnerved, you enter a place of utter stillness. If you leave the touristed spots and move a hundred yards away, down a graveled road, or up a dry boned ravine you will find it. You empty yourself, as it were, until there are no remnants of the noise of the world outside, aural or visual. There is only stillness. And into that inner stillness begins to seep the being of the outer stillness.

What was once monochrome gray or brown begins to show itself in stripes and subtleties, of oceans long gone, washing the mountains only God remembers down into the still coastal shallows when Nevada was the far edge of a much smaller place, idling its way up from the equator to where it now sits, waiting for California to come sailing in from the west and dock along its flanks.

What was once completely silent now gives way to the popping and crackling of salt as it grows up and out of the underground seeps and builds its fabulous miniature castles, towers and parapets, corbels and crenels. Where once no birds flew now there are one or two, swallows flaring through the sweet day in mating dance, then gone. A killdeer pipes sharply, then sharply is stilled. What was for a while a desolation shows bands and tufts of green – over there, just back here. In the nearness of time the native folk knew this, band after band finding food and water to sustain some years or more before moving on. I think in this place they did not chatter. Their speech was as spare as the land, as colored as the Artists Palette.

That’s why I come. Why I long to come, I think. Not just for the beauty, unexpected. Not just for the surprise of green trees popping up in the middle of the basin – though that begins to get at it. Not just for the exotic thrill of saying “I was there.”

But for the upending of ideas: that desert is beautiful; that desolation is rich with life. That life continues where life ought not. I come for the sensation of smallness, of transitoriness, of foreverness.

I come to find that shedding the clamor of the news, the every ten minute traffic reports, the every two minutes of ads reveals a richness that is buried beneath all that. Is always the same when I return. Endures and is the foundation.

I look at these quiet places and ask myself, would I like to live here, actually? Would the silence eventually rise up and press against the sociability that lives in us all. Would it drive me mad as stories tell of prairie pioneer women cut off from conversation, shared joys and sorrow? It’s not a choice I have now, wearing the light garment of other choices I have made, so I don’t linger on it. I am satisfied.

Like my earliest girlfriend who discovered, awe struck with Van Gogh’s “Starry Night” that having twenty postcards of it didn’t increase the pleasure. She gave them all away and lived with her remembrance. So I believe I come back to Death Valley, and will often, to empty my well as much as it is possible, to empty into emptiness, to find again the fullness of the silence where the bones of the mountains exude the fragrance of our own brief transit. To become strong out of silence.

Salt Castles
the Devil’s Golf Course
Salt Castles

Cactus Flowers

From Westside Road
Towards the Panamints

Snow on the Peaks
Salt in the Basin

Dan Dusicoe time exposure of Death Valley from the Racetrack

Galapagos Islands

Every day in the Galapagos Islands is like a day in a glass bottomed boat through which we peer — hundreds of thousands, even millions of years into the past. The island of Española, the closest of the 19 islands to Ecuador, is some 3.2 million years old. The youngest, and furthest from the mainland, is Fernandina, some 700,000 years old and, like most of the islands, lava formed from fire-nozzles of molten magma brought from miles below the drifting plates the oceans and continents sit upon.

On these tiny platforms are living creatures whose ancestors, very much like those we see, lived, begat and died in unbroken chains beyond our ability to comprehend, as if such lengths of time, carefully laid along all the neurons in our minds, would not fit.

It is not so much any individual sighting, or experience that amazes, as the whole taken as one. Yes, sea lions mimic our movements in the water when snorkeling; yes enormous yellow billed Waved Albatrosses barely move at our approach; yes Brown Noddys perch on the heads of Pelicans which have just dived, waiting for an opening of the enormous beaks to flash in and steal the catch. Sea turtle males mount and cling to the swimming females and copulate at the speed of sleep. Blue footed Boobies plummet from great heights and enter the water like torpedoes to snare their meals; Storm Petrels hover and seem to tap dance upon the waters to find theirs. Magnificent Frigatebirds, big as Turkey Vultures, swoop and nearly hover trying to steal a catch from a just resurfaced Booby. All these things are true and, if experienced alone, would be memorable. But being taken out of our own daily experience of newspapers, high-speed travel, multi-tasking, to-do-listing, shopping, pricing, judging and suspended for a week of days in eating, sleeping, walking, looking and absorbing is something of a different order. It is mind catching. It is time-travel.

It is to see at geological time, almost.

These birds, fish, amphibians, insects, plants (almost no land mammals) have lived in the round of days since some time after the first islands were formed, perhaps 14 million years ago. Nothing changes for them, as we humans understand change. Yes, the first islands are now eroded and sea-washed back into the sea, existing as sea-mounts closer to Ecuador and Costa Rica; yes, the Cocos Ridge, now buried under fathoms of ocean may have once been a land bridge from Central America to the early islands; yes storms come and yield to sun, rain increases in some years and declines in others; the temperatures over this thousand years is 2 degrees warmer on average than in that thousand years as the earth swings through its 3 great orbital cycles. All these things are change. Section 1,000 years from 3 million years ago and compare it to a thousand year section from 3 thousand years ago and we will see change, and yet, and yet this is not change, not as we humans, with memory, and future-fearing, and language, and writing experience it.

So, it is not that we are seeing precisely what we might see in the year 15,600,000 B.C. but that we are seeing –almost uninterrupted by the hand of man– what has come to us from then –wholly; not just one thing, not simply the Jurassic archaeopteryxical seeming Brown Pelicans, not just the sea turtles which come to us from before the Jurassic, their ancestors having survived the great asteroid that destroyed the dinosaurs 65 million years ago, but all of it — the living living on, and on, and on, living on the living, among the living and for the living.

It is not, of course, paradise, though the tour guides will claim it so. Tourism to the islands has increased some 110 fold in 40 years, from 1,000 or so per year in the 1960s to 110,000 last year. Even regulated and kept from more than day treks on most of the islands these are a lot of feet, and a lot of food carried in, and a lot of waste to be dealt with. We 16, on the smallest boat of the tourist fleet, were part of this loving onslaught.

On the first night, smoke rising over the salt bush and candelabra cactus, was said by our guide to be from open-pit burning of trash. A couple of species of the famous Darwin Finches, of which there are some 14, congregate along the periphery of the outdoor eating area at the Baltros airport on Santa Cruz island and act for all the world like urban House Sparrows, landing on uneaten food as soon as the swishing hand is gone — turning themselves, perhaps, in 100 years or so into yet another species: the Garbage Beaked Finch.

The first known humans set foot on one of the islands in 1535. Today, about 20,000 people live on three of the islands, concentrated into a few towns. The town of Puerto Ayoro on the southern coast of Santa Cruz boasts Internet Cafes, fine and shabby hotels, tour and diving boat companies and on New Year’s Eve, 2007, an all night big-amp outdoor party for several thousand people who could not dance to the music provided because bodies filled every millimeter. New Year’s Day at 9 a.m. found an urban garbage scene and public drunks plucked straight from any city in the western world. By noon the plastic bottles had been swept away and the drunks rolled up and out, testimony perhaps to the ever present billboards and public campaigns to “Preserve Your Heritage,” “Keep Santa Cruz Beautiful.”

The National Park Service of the Galapagos seems to be paying attention. Every tourist group is meant to be led by a guide. In one case we saw a uniformed guide actively suspicious of a small group who seemed to be without a guide. Pressure from the mainland, the companies who will profit, and the government which wants its portion, is intense, however. Requests for luxury hotels, more and bigger tour ships, more and bigger groups are constant, with weak and disorganized opposition.

Speaking of humans… Spending a week in close observation, in conversations with companions who were biologists, heavy reading [ Galapagos Diary, Galapagos: A Natural History, Charles Darwin: Voyaging ] I began to sense the notion of speciation settling in me, not just as passive knowledge but as something I could use myself to look at a scene and begin to piece together the what, the how and the when. As weather turns dry and arid plants replace temperate ones, and food source changes the birds change too; they must. Those with beaks to break the new seeds, or probe the new cactus flower, survive; those without do not. Knots of seal-pup carcasses on all the islands spoke of failure; fat and happy pups finding mom and nursing spoke of success.

My mind turns as it always does, to us, we humans, in all our exotic differences. There is a kind of speciation going on amongst us, at all times in all places. Not that we ever become separate species, but that we arrange ourselves as sub-species. We differentiate ourselves according to our environments as do other species but also, as humans, according to our remembered pasts and projected futures. We differentiate ourselves because we must, it seems –as do the finches. We differentiate ourselves from others, not only to survive in the elements and with the food we know but — unlike the finches– so that we can know who we are.

The great problem is that for all living things but us species differentiation has a built in “enough.” The struggle for survival, except for us, does not allow one species to exterminate another. As the food supply diminishes so do those who depend upon it. The fighting within a species for dominance and place has an “enough.” Losers back down. The fight is over. The sea lion harem is 10 – 20 females. This is the “enough.” The bull does not keep on to 200, 2000, does not control an area beyond his range and food supply. Unlike us.

Learning to live in the world with the expectation that our grandchildren’s grandchildren’s grandchildren will see it and love it as we do, means understanding our own differentiation. It comes out of our DNA deep history. It also means finding our own “enoughness.” It means we have to differentiate away from the all-consuming, all-dominating, all-voracious species we have become and find our satisfactions, our completion, in “enough.” It may be this sense of enough is built into us as it is to our great skein of cousins. If so, our other gifts have obscured it, have overwhelmed it, until it is very possible to imagine the end of our days. There is much to be done, and un-done; there is much we could do by not doing, by leaving alone. From somewhere, we all hope, the ways will be found, whether from wisdom from afar or wisdom already within.

So may it be. All of our days.

[cross posted at]

Photos at