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The climatic cost of our high-carb diet

Scientists say our love of hydrocarbons sending mountain communities into uncharted territory

Danger in Degrees, part 1

Earlier this year Allen Best, the Colorado writer who compiles the Mountain News, wrote a seven-part series for the Aspen Times on climate change and the mountains. Part 1 of the series appears here; a second part will be featured next week in Pique.

Hiking along the Continental Divide north of Georgetown, Colorado during late summer three years ago, Ed Knapp noticed something awry. Several feet below the lip of a withering field of ice and snow was a skull with down-turning horns. It was, he quickly concluded, the skull of a bison.

Bison skulls in the Rocky Mountains are by no means rare, even if none had ever been found quite so high, at nearly 13,000 feet in elevation. The surprise was the rapid retreat of ice from which the bison skull emerged. When Knapp, a 60-year-old building contractor from metropolitan Denver, began hiking the Continental Divide near Jones Pass in the 1970s, the permanent snowfield had been 200 metres long. A year after it yielded the skull, it vanished altogether.

Make no mistake, the climate is shifting across North America and the world. The 10 warmest years since record-taking began have occurred since 1983. Mountain glaciers have been reduced by about half. Sea levels are up 6 to 10 inches. Severe heat waves have become more frequent.

In the mountains, evidence of warming is found at every turn. Winter nights are less frigid. Spring runoff comes earlier. The frost-free season has expanded — in Aspen by more than three weeks, according to recordings kept since 1949 at the town’s water plant.

The David Suzuki Foundation, which launched the Melting Mountains awareness program in February 2003, in co-operation with the Alpine Club of Canada and Mountain Equipment Co-op, calls mountains nature’s water towers. The Suzuki Foundation says that in the Canadian Rockies, late summer river flows have decreased due to the drastic reduction in glacial cover over the past century.

But do not make too much of local or even regional weather, says Susan Salomon, a scientists from Boulder, Colorado renowned for her pivotal role in research about the ozone hole over Antarctica. “Climate varies in your backyard much more than it does in the global mean,” she says. “We have to be very careful in trying to attribute local variations to global warming.”

That said, there’s no question the globe is warming. Some change may well be due to natural climate change, but the broader evidence of climatic change is beginning to add up. Nearly all scientists now agree that people — primarily through the burning of coal, petroleum and other fossil fuels that create greenhouse gases — are the main reason.

The new consensus

Those questions about the critical role of greenhouse gases 15 years ago were at the core of a lively debate. There was no strong consensus among scientists, much less the public.

But the huge body of research conducted since then has left few scientists as doubters. Global atmospheric concentrations of carbon dioxide, the most common greenhouse gas, rose 20 per cent during the 20 th century. As the century closed, temperatures spiked dramatically in what many researchers think was a direct result of these gases.

“It’s almost impossible to find a scientific researcher who doubts the connection between people and greenhouse warming, and that we’re in for an unprecedented warming during the next 100 years,” says John Harte, a professor at the University of California at Berkeley who spends his summers conducting global warming-related experiments near Crested Butte, Colorado.

Yes, you can find Web sites that dismiss the human fingerprints on global warming as bad or at least unproven science. But Harte points out that until recently, there were scientists and spokesmen for the tobacco companies who questioned any link between cigarettes and cancer. “That’s exactly what’s going on in the global warming debate,” says Harte.

That’s not to say that scientists know exactly where the climate is headed. They do not. Climate change is enormously complicated. The slight wobble in the Earth’s orbit around the Sun causes shifts from swamps to glaciers. Drifting continents also provoke climatic shifts.

The mechanics of these climate changes are only poorly understood. Particularly puzzling is the role of carbon, which is continually being redistributed among the plants, the ocean, and the atmosphere. Clouds are another major mystery.

All of this means that scientists are far from figuring out how climates shift naturally. With this sinister Joker of growing greenhouse gases in the playing deck, the game is even more difficult to figure out. But what should disquiet anybody is that, in the absence of action to reduce the burning of fossil fuels, carbon concentrations at the end of this century will be higher than they have been in 20 million years — long before people were on the planet.

Century’s top issue

That makes climate change, as many observers have noted, the paramount issue for the 21 st century. It is an environmental problem unlike any other ever faced.

Most environmental problems have local causes, with local solutions. But local becomes global very quickly in the atmosphere.

The air circumnavigates the globe in about two weeks at the same latitude. In other words, the pollution from Vancouver – or the emissions from your car on Highway 99 — hit Toronto in a few days, Athens in about a week, and Beijing and Tokyo a few days later before returning home.

But the air mixes over time. It takes one year for the air on one hemisphere to thoroughly mix. Within two years, the global atmosphere will have become one big punch bowl.

A second way that the accumulating greenhouse gases are unlike more conventional environmental problems is the cumulative effect and lag time. Once put into the atmosphere, carbon dioxide stays there for 100 years or more.

Hence, the heating in the year 2030 will be the result of pollution from that year, but also this year — and from the year you were born, the year your mother was born, even the year that Beethoven was born. It takes probably thousands of years for the gases to dissipate.

“The problem we are creating has a 10,000-year effect,” says Duane R. Kitzis, a scientist with the National Oceanic and Atmospheric Administration in Boulder.

>Scientists, as weathermen have begun doing, always carefully couch predictions about the effects of global warming in terms of probability. A prediction issued last December by two scientists from Boulder, Thomas Karl and Kevin Trenbert, has the sort of odds you’d like in Las Vegas.

There is, they said, a 90 per cent probability that between the years 1990 and 2100, global temperatures will rise by 3.1 Fahrenheit to 8.9 degrees Fahrenheit.

Anywhere within that band of 5.8 degrees will mean a major shift in your neighbourhood. That means a shorter snow season but a longer gardening season — if, that is, there’s enough water.

Entire civilizations have been brought to their knees by even lesser climatic shifts than are now being contemplated, as witnessed by the exodus of the Ancestral Pueblo from Chaco Canyon and Mesa Verde.

Already, the relatively comfortable warmth we have come to think of as “normal” is very much unusual in the broad sweep of the Earth’s recent history. New ice cores drilled in the ice at Greenland and Antarctica have given paleoclimatologists, the scientists who study climate history, a glimpse of the Earth’s changing climates as far back as 740,000 years. It’s been a chilly time.

<“It’s worth noting that in the past 430,000 years, the percentage of time that climate was as warm as it is today is quite small, about 5 to 10 per cent, and before that time, it appears to never have been that warm,” writes James W. C. White in the June 11 issue of Science magazine. “Our current climate appears to be a rarity, if not an anomaly.”

Glaciers have repeatedly come and gone. Lulls of 4,000 to 6,000 years have been most common between these glacial advances. However, the current lull since glaciers last advanced into Wisconsin and New York has lasted 12,000 years, points out White, who directs the Environmental Studies Program at the University of Colorado-Boulder.

White points out the possibility that our civilization has advanced this far because of this unusual climate stability. Anthropologists say we’re not smarter than Neanderthal man, just luckier. We drew the climatic breaks.

When the bison died

But even within this current calm have been changes. Paleoclimatologists studying such things as tree pollen in the soil say that treeline on

Mt. Evans, the 14,000-foot peak south of Idaho Springs, Colorado, once was nearly 2,000 feet higher. Another time during this period of relative stability the treeline was nearly 1,000 feet lower.

Temperatures of today were reached about 9,000 to 8,500 years ago, after which the Rocky Mountains began to warm considerably, peaking at about 7,000 to 5,000 years ago. After that, with a few modest periods of warming, we have been easing very slowly, very gradually, back toward ice.

The bison calf at Jones Pass, north of Georgetown, died near the beginning of one of those cooler interludes, at around 1560, according to radiocarbon tests. That was near the start of what is called the Little Ice Age, when small glaciers in the Rocky Mountains grew once again until the 1850s, just before the gold rush into Colorado.

For most of a century, there was a heating trend once again. But cooling returned from the 1940s to the 1970s, causing scientists to speculate once more about the return of another ice age.

Some scientists have even suggested that man’s addition of greenhouse gases about 6,000 years ago, with more carbon dioxide from biomass burning and more methane from the growing of rice, has kept the next ice age at bay.

But all of this is a gamble, say most scientists. Our climate, they say, could be like a washing machine on spin cycle. At the rate we’re loading carbon, nitrous oxide and other greenhouse gases into the sky, we may throw the climatic machine off-balance. What is becoming clear about the past is that the more unstable the Earth’s climate, the more likely it is to change abruptly.

One theory is that the Earth could be flung back into an ice age. The more immediate concern, however, is heat — steady, unrelenting increases in heat.

Whether by fire or ice, however, we are forcing change upon the Earth’s climate, and few scientists are optimistic that we can find an easy technological cure once the greenhouse gases are in the atmosphere. The issue is how we can lessen our reliance upon fossil fuels, the primary source of those gases, even as the world’s population swells.

“It's not an emergency in the sense that if we don't do anything this year, we die next year,” notes Randy Udall, a writer who has spent a decade learning about climatic change. “The climate scientists like to say that ‘one year's emissions don't matter that much.’ That is because the cumulative total will control the extent of the warming.

“But it is an emergency in the sense of the magnitude of the change in energy systems required. In that sense, there's no time to waste.”



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