An article in the November 1 issue of Science sets out the challenges. Entitled “Advanced Technology Paths to Global Climate Stability: Energy for a Greenhouse Planet,” it was written by a team of 18 scientists and engineers from major universities (including McGill), U.S. government laboratories and agencies, and even Exxon Mobil. The U.S. Department of Energy funded the project.

The level of carbon dioxide in the atmosphere has increased from 275 to 370 parts per million in the past century. Unchecked, it will pass 550 parts per million this century. Climate models and the study of past climate changes indicate that that could warm Earth’s climate as much as it cooled during the last Ice Age. Stabilizing the level of CO2 lower than that will require “Herculean efforts,” the authors conclude.

The world today requires 12 terawatts (12 trillion watts) of power generating capacity, of which 85 percent is fossil-fueled. Power requirements continue to soar as the world’s economy continues to grow. Stabilizing the level of CO2 in the atmosphere by mid-century while permitting the current level of economic growth will require 30 terawatts of carbon-free power production, the study estimates–and we don’t have the technology to achieve that.

Possible sources of carbon-free power include hydrogen, biomass, solar thermal and photovoltaic, wind, hydropower, ocean thermal, geothermal and tidal.

Hydrogen sounds good, but doesn’t exist in geological reservoirs, which means it is usually extracted from hydrocarbons–and per unit of heat generated, more CO2 is produced by making hydrogen from fossil fuel than by burning the fossil fuel directly.

The other sources mentioned currently provide less than one percent of the world’s power, and all suffer from the same problem: low power production per area. For example, producing 10 terawatts of energy using biomass would require more than 10 percent of the Earth’s surface, roughly equivalent to the area covered by all of human agriculture, and a solar array that could produce 10 terawatts would cover a square 470 kilometres on a side. (All the photovoltaic cells shipped from 1982 to 1998 would cover a square only three kilometers on a side.)

Even if we could scale up solar arrays and windmill farms to meet our needs, existing power grids, designed for centralized power plants, couldn’t manage the loads. So another challenge we face this century may be the complete reengineering of our electrical distribution systems.

Another way to harness solar energy is the space solar power satellite, a huge solar array in space that transmits power to Earth by microwave. But getting 10 terawatts of power to Earth by this method would require 660 orbiting solar arrays, each the size of the island of Manhattan. Launch costs, note the study’s authors with admirable understatement, are likely to be “high.”

What about nuclear power? Well, fission, our current method of nuclear energy generation, not only creates radioactive waste and lends itself to the proliferation of nuclear weapons, it’s based on a non-renewable resource, uranium. Meeting the mid-century power needs using fission, the study’s authors estimate, would use up the world’s known reserves in just six to 30 years.

The best hope for a long-term energy solution remains fusion. Fission releases energy through by splitting a large atom (that of uranium); fusion, which powers the sun, releases energy by fusing two small atoms (of forms of hydrogen) together. Fusion powers the sun. Current research has brought fusion power close to the break-even point, at which the amount of energy produced by the fusion reaction is equal to the amount of energy required to bring about the fusion reaction. But fusion power plants are still years away.

The study’s authors believe a massive Apollo-style research and development program will be required to ready new power sources for the world in time to stabilize the CO2 levels in the atmosphere at a reasonable level…and time’s a-wasting.

“Combating global warming by radical restructuring of the global energy system could be the technology challenge of the century,” the authors conclude. “…Stabilizing climate is not easy. At the very least, it requires political will, targeted research and development and international cooperation. Most of all, it requires the recognition that…the fossil fuel greenhouse effect is an energy problem that cannot be simply regulated away.”

Primitive, industrial-revolution technology has gotten us into this mess; it will take advanced, futuristic technology to get us out.

Two Canadian scientists will climb to very Mt. Logan’s 5,959-metre peak and extract a 225-metre cylinder of ice from its glaciers. A core was taken in 1980, but the technology didn’t exist then to take one as long as will be taken this time–and the longer the ice core, the farther into the past you can look. 

Obviously the scientists won’t be dragging a quarter-kilometre long icicle down the mountain intact, and no, they won’t just point it downhill and give it a shove, either.  Instead, they’ll cut the core into one-metre slices, which will be left on the mountain until next spring, when they’ll be retrieved and shipped via refrigerated trucks and airplanes to Ottawa.  There, scientists from the Unites States, Japan and Sweden will examine the ice.

 Among other things, they’ll be able to tell how snowfall has varied from year to year.  They may find volcanic ash from eruptions that took place around 4000 B.C. in the Aleutian mountain range in Alaska, or airborne pollen from Siberia, China or Japan.  They may also find air bubbles containing samples of the atmosphere from thousands of years ago–analysis of such air bubbles is one way we know there is more carbon dioxide in the air now than there was before the Industrial Revolution. 

The study of past climate is called paleoclimatology.  Studying ice cores is one of the best ways to gather clues about ancient climates, but it’s not the only way.

 In tropical climates, for instance, ice cores are hard to come by.  Instead, scientists examine coral reefs.  Corals build their skeletons from calcium carbonate, extracted from sea water. The calcium carbonate contains various forms of oxygen and different trace metals, depending on the temperature of the water in which it grew.  By examining the coral skeleton, scientists can tell how warm the water was when it was formed.

 As I mentioned, pollen is one of the things scientists will be looking for in the Mt. Logan ice core.  Pollen can also be found preserved in the layers of sediment at the bottom of a body of water.  Because each type of plant produces pollen grains with a distinct shape, fossil pollen tells scientists what kinds of plants were growing in the distant past–and that the climate must have been favorable to those species. 

Tree rings are another source of information.  As every schoolchild knows, trees produce one ring a year in temperate regions.  The width, density and composition each ring are influenced by the climate that year.  Since trees live hundreds, even thousands, of years, they provide a continuous, year-by-year record of climate change.

Ocean sediments are another source of data.  Every year, between six and 11 billion tonnes of sediment settles to the bottom of the world’s oceans and lakes. By drilling out cores of this sediment and examining the chemicals and tiny fossils trapped in it, scientist can get an additional glimpse of past climate.

 The favorite places to drill for ice cores are isolated mountain tops and in the Arctic and Antarctic, not just because that’s where the ice is, but also because their very isolation makes it less likely that local human activities have contaminated the site.  Mount Logan, located on the Yukon-Alaska border, is ideal because very few people, except for a handful of climbers, have ever been anywhere near it.  It’s also of interest because, although scientists have recently taken ice cores from Greenland and Canada’s eastern Arctic, they haven’t yet studied climate change on the Pacific Ocean side of North America — even though that’s where our weather comes from.

 On the other hand, its isolation makes the expedition more difficult.  High on the mountain, even in the summertime, storms are frequent and temperatures drop to -30.  The air is dangerously thin and the ultraviolet radiation dangerously high.

 It won’t be an easy or comfortable expedition, but the opportunity to examine a 10,000-year unbroken record of climate change is worth it, if it tells us more about how the North American climate has changed over the millennia–and helps us project how it will change, under humanity’s influence, in the future.

The term “greenhouse effect” is usually used today in reference to a predicted gradual warming of the Earth caused by an increase in various gases in the atmosphere, primarily due to human activity.

Really, however, the greenhouse effect has been at work for eons, which is a good thing, because it’s what keeps Earth’s mean surface temperature high enough (17 degrees Celsius) for life to thrive.

About 40 percent of the energy we receive from the sun arrives at such short wavelengths that it zips through the atmosphere unimpeded. It warms the ground, however, which then radiates heat back at a much longer wavelength–a wavelength which certain gases, especially carbon dioxide and methane, absorb. This heats them, and thus warms the entire atmosphere.

The amount of greenhouse gases and the mean surface temperature have varied over Earth’s lifetime. The temperature has been so cold much of the planet was covered with ice, and so warm sub-tropical flora and fauna flourished at the poles.

Currently, the amount of carbon dioxide in the atmosphere is on the rise, due primarily to the burning of fossil fuels and the cutting down of forests (trees remove carbon dioxide from the air, but once they’re dead, they release carbon dioxide back into the atmosphere as they burn or decompose). Before the Industrial Revolution, the atmosphere contained about 280 parts per million of carbon dioxide. Today, it contains 360 parts per million, and the Intergovernmental Panel on Climate Change, an assembly of Earth’s top climatologists, estimates that by the end of the 21st century, that level could be anywhere from 480 to 800 ppm.

Methane, produced when bacteria decompose organic matter, has also increased due to human activities, including raising livestock, wetland rice farming and the disposal and treatment of garbage and human and animal wastes.

The IPCC estimates that carbon dioxide levels of 560 ppm could cause an increase of 1.1 to 3.3 degrees Celsius in the planet’s average temperature next century. Considering Canadian winters, that doesn’t sound too bad or too extreme. But consider: during the last ice age, when three kilometres of ice covered most of North America, the average temperature was only 2.5 to 5 degrees cooler than it is now. Even slight changes can have huge effects.

The possible consequences are frightening. Some forests could become grasslands; some grasslands (southern Saskatchewan, perhaps?) deserts. Longer, hotter summers and shorter, milder winters could be punctuated by more extreme storms, leading to floods and other weather disasters. Species unable to adapt could become extinct; familiar songbirds and animals like polar bears and manatees could vanish forever. Coastal cities could suffer from rising sea levels and more powerful hurricanes. Mosquitoes could become more plentiful, and carry tropical diseases like malaria and dengue fever further north. Crop failures could result in a huge worldwide refugee problem.

Environmentalists can point to plenty of other horrendous possibilities. What they can’t do–yet–is prove that human-induced warming has already begun.

It’s true that the IPCC stated in 1995 that “the balance of evidence suggests that there is a discernible human influence on global climate.” It reached that conclusion because the average temperature of the planet has increased by about half a degree this century, and because that warming has occurred in the fashion predicted by the most sophisticated computer models.

However, since then, new models and new discoveries have added new uncertainty. Many scientists believe it will be another 10 years before we can say unambiguously that we have seen the “fingerprint” of human activity in global warming.

Those who fear the economic consequences of possible legislated efforts to reduce greenhouse gas emissions point to this uncertainty as good reason to hold off on any action. But even most of the scientists who say human-induced warming has not yet begun don’t doubt that it will. This century’s warming apparently falls within natural variations in climate–but that doesn’t mean humans didn’t cause it. And out basic understanding of the greenhouse effect tells us that increased levels of carbon dioxide in the atmosphere must eventually cause warming.

As a result, governments worldwide are faced with an unpleasant choice: do nothing, or too little, and face possible catastrophe, or reduce emissions of greenhouse gases, and face the wrath of an inconvenienced public.

I don’t envy them–but for all our sakes, I hope they make the right choice.

While it’s true that science has yet to come flat out and say that global warming, the anticipated result of mankind’s pumping of billions of tonnes of heat-trapping carbon dioxide and other gases into the atmosphere every year, has unequivocally begun, the evidence is mounting–and one place where the evidence may soon become crystal clear is Antarctica.

As far back as 1978, a paper in the science journal Nature suggested that scientists would see the first evidence of global warming in Antarctica. And what they’ve seen in the last few years is exactly what they would expect if global warming were already underway–although, they always hasten to add, there’s still a possibility that the changes Antarctica is undergoing are related to some natural cycle we don’t know about yet.

But those changes are massive. Over the whole of Antarctica, temperatures have increased an average of about one degree Celsius over the past 50 years, according to David G. Vaughan, a glaciologist at the British Antarctic Survey in Cambridge, England–and on the Antarctic Peninsula, which extends outward toward the southern tip of South America, temperatures have risen an average of 2.5 degrees Celsius since record-keeping began in the 1950s.

As a result, massive ice shelves have begun to break up. Between January 14 and February 27 last year, an ice shelf that formerly blocked the Prince Gustav Channel between James Ross Island and the peninsula broke up, which means that, for the first time in recorded history, James Ross Island can be circumnavigated.

During the same period, the northern section of another ice shelf, the Larsen, disintegrated, crumbling into a plume of debris extending 200 kilometres. And further south, an iceberg roughly the size of Luxembourg–37 kilometres wide, 77 kilometres long and 183 metres thick–also calved off the Larsen Ice Shelf. Another huge ice shelf, the Wordie, has also recently disappeared.

Although the giant iceberg drew the most media attention, the real shocker to scientists was the disappearance of the ice shelves. If you have an old–or even a new–school atlas lying around, you’ll see those vanished ice shelves included on the map of Antarctica as permanent fixtures. That they could collapse in such a relatively short period of time could be an ominous harbinger of other dramatic changes soon to come as the planet warms up.

The disappearance of the ice shelves isn’t the only change to Antarctica. On another ice shelf, the Wilkins, summer–defined as the period during which ice melts (which is a pretty good definition for Saskatchewan, too, actually) has increased from 60 to 90 days in just over a decade. As well, parts of the “white continent” are becoming increasingly green. Antarctica has only two species of flowering plant. Since 1964, the Antarctic pearlwort has increased sixfold, and Antarctic hairgrass has become 25 times more common.

So why aren’t scientists absolutely convinced that all this is related to global warming? Because the Antarctic Peninsula is more prone to temperature fluctuations than most places, due to the complex interactions of winds, ocean currents and ice. Nevertheless, what’s happening there matches very well with predictions of global warming’s effects.

Scientists would like very much to know what happened to the Antarctic ice cap in the Pliocene Epoch, three to four million years ago, when the Earth was approximately as warm as mankind’s efforts may make it in the next few centuries. If the Antarctic ice cap melted then, it may melt again–and that would be a disaster of unimaginable proportions, because the Antarctic ice cap averages 2.5 kilometres in depth, and if it melted, it would raise the sea level by 74 metres–which means you could take a boat to the 20th story of the Empire State Building.

At the moment, scientists aren’t sure what will happen, because even though the ice shelves seem to be slowly disintegrating, they don’t effect the sea level. It’s the land-based glaciers that could cause the problem, and at the moment, scientists don’t even know whether the ice sheet is getting thicker or thinner. They’ve begun the process of finding out, however, and the results of that data should be of great concern to all of us.

If the melting of Antarctica truly is underway, a lot more than just that continent’s shorelines are going to change.

But I prefer that ice keep to its proper place–which is not on the roads, on the sidewalks, or especially on my car.

Still, if you think chipping half a centimetre of ice off your driveway is a chore, just imagine trying to clear away three kilometres of the stuff. Twenty thousand years ago, that’s the task you would have faced.

Scientists believe the Earth is about 4.6 billion years old, and it’s mostly been much warmer than it is now. But periodically it has cooled off, for anywhere from 2.5 to 60 million years. These cold epochs are called ice ages.

Within these epochs, there are “glacials”–periods when glaciers cover much of the Earth–and “interglacials”–periods when the glaciers retreat. The term “ice age” can also refer to a specific glacial periods. In fact, most people refer to the most recent glacial, the Wisconsin, which ended 10,000 years ago, as “The Ice Age,” as though there had been only one, when in fact there have been many.

Glaciers grow when the amount of snow falling on them in the winter is greater than the amount that melts in the summer. The snow piles up, and is eventually compressed by its own weight into ice. Its vast weight also causes it to spread out, rather like certain of us do when we sit down.

During the Wisconsin glacial, all of Canada was buried under three kilometres of ice, just like Greenland and Antarctica are today. The ice spread out from the poles and mountains to as far south as Missouri.

This didn’t happen overnight. In fact, it happened at a, well, glacial pace: probably something between 50 and 150 metres a year.

What causes ice ages? Scientists aren’t sure. There are so many interrelated factors it’s hard to separate cause from effect.

For example, it’s known that the stratosphere was 10 times dustier during the last glacial. Dust could have blocked sunlight, cooling the Earth. Was volcanic activity high? There’s no evidence for it. Maybe the dust simply blew off of ocean shelves exposed by dropping sea levels, and is therefore an effect, not a cause.

Winds were stronger, causing more clouds and precipitation, further cooling the Earth. Cooler seas absorbed more carbon dioxide from the air, reducing the greenhouse effect. Ocean currents changed, no longer delivering warm water to the north. Highly reflective sea ice spread, bouncing energy back into space. And the vast sheets of ice themselves cooled the atmosphere flowing over them. All of these things contribute to an ice age, but none appears to be the trigger. For that, many scientists believe, you have to look to outer space.

Ice ages occur about every 150 million years. It so happens that the Milky Way galaxy rotates once every 300 million years, taking our solar system through denser and thinner regions of interstellar dust and changing gravity and magnetic fields. Twice an orbit, every 150 million years, a slight change takes place in the solar system’s galactic environment…which could cool Earth’s climate.

The glacials and interglacials within an ice-age epoch have their own cycle of about 100,000 years. These fluctuations appear to be related to a large extent (although not entirely) to variations in the Earth’s orbit: eccentricity, equatorial tilt and precession. Eccentricity, the variation of the Earth’s orbit from perfectly circular, has a cycle of 93,408 years. When the orbit dips closer to the sun, the spin rate of the Earth/Moon system slows, increasing Earth’s magnetic field. This more effectively screens high-energy particles from the sun and cools the Earth.

The planet’s tilt changes over a 41,000-year period; the greater the tilt, the more extreme the seasons. Finally, there’s the 25,920-year precession cycle. (Precession is the planetary equivalent of the wobble in a spinning top.) This, too, can effect the severity of the seasons.

Many scientists believe we’re living in an ice age right now; we’re only in an interglacial period, and the glaciers are due back in about 23,000 years.

The last glaciation shaped all of Canada’s geography, forming lakes, scouring valleys, even giving the southern Prairies their rich farmland (which formed at the bottom of giant Lake Agassiz, created by the run-off from melting glaciers).

This country was shaped by ice, and I’m sure we’re all very grateful…but as winter stares us in the face again, I’d have to say ice has out-stayed its welcome.

Let’s keep it in our drinks where it belongs!

The term “greenhouse effect,” as usually used today, refers to the predicted gradual warming of the Earth due to an increase in various gases in the atmosphere, primarily due to man’s activities. There is considerable debate as to just how serious this warming is going to be–and whether it has begun yet. (Despite the warmth of the ’80s in our part of the world, the most recent and most accurate study of the Earth’s temperature, carried out by satellites over the last decade, shows no evidence of global warming or cooling.)

However, in a broader sense the greenhouse effect has been at work for eons, which is a good thing, because if it hadn’t been, we probably wouldn’t be here. That’s because the greenhouse effect is what keeps the mean surface temperature high enough (currently it’s 17 degrees) for life to thrive.

About 40 percent of the energy we receive from the sun is shortwave radiation, to which the atmosphere is transparent. This radiation warms the ground, which radiates heat back at a much longer wavelength. Most gases are transparent to this longer-wavelength radiation, but not all. The so-called greenhouse gases, especially carbon dioxide (though others are also involved), absorb it, instead–and heat up, warming the other gases in the atmosphere at the same time.

The amount of carbon dioxide in the air and the mean surface temperature are far from carved in stone. The surface temperature has, in the past, been both so much colder that much of the planet was covered with ice, and so much warmer that even near the poles sub-tropical flora and fauna flourished.

However, the current increase in carbon dioxide is quite rapid, and due almost entirely to human activities, especially the burning of fossil fuels. It’s estimated carbon dioxide levels are 25 percent higher now than they were in 1860. Some scientists predict that by 2050 this increase in carbon dioxide could boost global mean temperatures from two to five degrees.

Considering Saskatchewan winters, that doesn’t sound so bad. But look at some of the possible consequences: shifting weather patterns could bring drought to once-fertile areas (like Saskatchewan?) and heavy rains to fragile deserts; run-off from melting glaciers and the expansion of warming seawater could raise sea levels six feet, inundating low-lying coastal areas and islands; hurricanes could increase in frequency and severity.

Probably some parts of the globe would actually benefit, but the atmosphere is so incredibly complex that there is no way of predicting the precise effect on any area–just as no one can accurately predict the weather more than a few days in advance.

This should mean that all countries have an equal stake in dealing with the problem. While it is generally conceded it is impossible to halt the greenhouse effect, it can be slowed, “simply” by cutting fossil fuel usage.

Of course, that’s not really simple at all. Developed countries such as our own aren’t anxious to give up the comforts and conveniences purchased with high energy usage, and less-developed countries are understandably unhappy with suggestions that they should not be allowed to follow the same industrialized route to prosperity as the developed nations.

Still, there are steps to be taken. Energy conservation techniques such as were all the rage during the 1970s’ energy crisis should be continued and expanded. Just because oil is currently cheap is no reason to burn it profligately. To do so could be costing us a lot more than just a few dollars.

On a broader scale, countries must develop energy sources other than coal and oil. Natural gas, for example, produces half as much carbon dioxide per unit of energy as coal, and solar power, wind power, geothermal power and nuclear power, though they have their own problems, produce no greenhouse gases at all.

Some scientists are already thinking of more direct methods of attacking the problem–and before dismissing them as wildly farfetched and hopelessly expensive, consider the cost of building coastal walls to keep out the rising ocean.

Plant more forests, says George Woodwell, director of the Woods Hole Research Center in Massachusetts. About 1.86 million square kilometres of new forest (4.5 times the area of California) would take care of a third of the carbon dioxide problem (assuming we stop cutting down the forests we already have).

Spread phosphates in the ocean, or use large orbiting reflectors to beam extra sunlight into the polar seas, to promote blooms of phytoplankton, suggests climatologist Roger Revelle of the University of California in San Diego. Phytoplankton use carbon dioxide in photosynthesis, then when they die take it with them to the ocean floor, where it remains for centuries.

Volcanos cool the earth by spewing sulfur dioxide, notes Wallace Broecker, a geochemist at Columbia University; we could load the upper atmosphere with sulfur dioxide, using a fleet of 700 jumbo jets working around the clock for year after year after year. (Aside from the logistical problems, this has one other slight disadvantage: sulfur dioxide promotes acid rain.)

There are other suggestions: painting every roof on every building on Earth white to reflect more sunlight, for example, or building giant orbiting parasols (10 million square kiometres’ worth) to block out the sun, or…

Or maybe we should just look harder for alternatives to fossil fuels and use less of them in the meantime.

Sounds a lot simpler, doesn’t it?