Carbon dioxide, produced by burning fossil fuel--coal, oil, and natural gas--is the largest single waste product of modern industrial society. Global carbon emissions to the atmosphere in 1997 will amount to more than six billion tons--more than a ton for every human being on the planet. With approximately 5 percent of the world's population, the United States accounts for 22 percent of global carbon dioxide emissions. The People's Republic of China recently surpassed the former Soviet Union as the second largest national source of emissions. Given current trends, there is little doubt that China will soon be number one, and that she will eventually set the pace for the future.
Because it is an invisible, nontoxic gas which occurs naturally, human-generated emissions of carbon dioxide might not appear troublesome. After all, carbon dioxide is generally beneficial to plants, providing, with water, the essential material input for photosynthesis. In fact, outside a narrow scientific constituency, carbon dioxide drew relatively little concern as a pollutant until recently.
Carbon dioxide moved to center stage when the Earth Summit, held in Rio de Janeiro in 1992, focused attention on its role as a "greenhouse" gas. The physical basis for the "greenhouse effect" is straightforward and non-controversial. Imagine what would happen if you added insulation to your house in winter but opted to burn oil in your furnace at the same rate as before: there is no doubt that the interior would warm up. Carbon dioxide, allowing free penetration of visible solar energy to the Earth's surface while inhibiting emission of infrared (heat) radiation to space, is an important component of the Earth's insulation. If we add carbon dioxide but maintain the supply of fuel (solar energy) to the terrestrial furnace, we may confidently expect an increase in surface temperatures.
Over the past 200 years--the period of industrial development--the concentration of carbon dioxide in the atmosphere has risen from about 280 parts per million by volume (ppmv) to close to 360 ppmv today. Burning of fossil fuel is primarily responsible, though deforestation--primarily in the tropics--also contributes as the plant matter is burned, releasing stored carbon to the atmosphere. (The latter effect is offset to some extent by regrowth of vegetation, which reabsorbs the gas from the atmosphere, accumulating it in the wood of trunks and limbs, primarily at mid latitudes of the northern hemisphere.)
Even under the most optimistic scenarios envisaged by the Intergovernmental Panel on Climate Change (IPCC), carbon dioxide is expected to climb to near 600 ppmv during the next century, more than twice the level that persisted for 10,000 years since the end of the last ice age. Within the lifetime of today's college students, it is likely to approach values not seen since dinosaurs roamed the earth 60 million years ago. Moreover, vestiges of carbon added to the atmosphere by mining and burning fossil fuel since the dawn of the Industrial Revolution will persist for hundreds of thousands of years. Contemporary transfer of carbon from fossil sedimentary reservoirs to the atmosphere constitutes what the late Roger Revelle, a distinguished oceanographer and first director of Harvard's Center for Population Studies, termed man's first great inadvertent global geophysical experiment.
International strategies to deal with the challenge of climate change are developed under the Framework Convention on Climate Change (FCCC), established by consensus of 172 nations represented at the Rio summit. With strong support from European countries and a group of small island nations especially threatened by the prospect of a significant future rise in sea level, the FCCC is expected, at its meeting in Kyoto late this year, to recommend binding targets that restrict future emissions of greenhouse gases from industrial nations.
It is unclear precisely what proposals the United States will bring to the table in light of strong domestic resistance to emission controls from an alliance representing, inter alia, the energy industry, organized labor, and conservatives opposed to government interference with the market. These opponents adopt a variety of positions: some question the scientific basis for concluding that emissions of greenhouse gases affect climate; others question the wisdom of a treaty limiting emissions from industrial nations without addressing contributions from large developing countries such as China; still others worry that a treaty would be ineffective, resulting merely in a transfer of jobs from energy-intensive, but efficient, sectors of the U.S. economy to unregulated, inefficient competitors elsewhere in the world.
Is the science sound? Summarizing results from various mathematical models designed to simulate past, present, and future climate (known as General Circulation Models, or GCMs), the IPCC concluded that the increase in greenhouse gases anticipated to occur during the next century may be expected to cause a rise in global average temperature of between 1 and 3.5 degrees Centigrade. They concluded that the temperature increase that has taken place already in this century (about 0.5 degree Centigrade) "is unlikely to be entirely natural in origin" and that "the balance of the evidence suggests that there is discernible human influence on climate." Sea level has risen by between 10 and 25 centimeters globally during the past 100 years; the IPCC suggested that it was likely to rise by a further 50 centimeters during the next century.
An increase in sea level of 50 centimeters seems small but would be sufficient to inundate an area of more than 40,000 square kilometers in China alone and would have even more serious consequences for densely populated, low-lying countries such as Bangladesh. It would also be associated with intrusion of salt water into freshwater aquifers worldwide and could exacerbate damage from coastal storms.
|China has compressed the cycle of industrial revolution--and enormously increased its scale. The use of coal and other fossil fuels in manufacturing centers such as Guangzhou, above, and Shanghai, lower right, makes China the second largest national source of carbon dioxide emissions in the world. Ron McMillan-Gamma Liason|
The IPCC results, reflecting contributions from more than 2,000 scientists from around the world, are challenged by a small minority of skeptics. With ready access to the editorial pages of conservative papers such as the Wall Street Journal and the Washington Times, these skeptics have had an influence on public opinion far beyond what can be justified either by their numbers or professional competence. In part, they focus on deficiencies of the current generation of climate models. To be sure, the models are imperfect.
But uncertainty is a two-edged sword. And even modest changes in climate can have serious consequences. The United States experienced unusually large losses from weather-related causes over the last several years: tens of billions of dollars in damages from unseasonable rains in California, floods in the Midwest, and hurricanes in Florida. Floods in south and central China were responsible for more than a thousand deaths in each of the summers of 1994, 1995, and 1996, while at the same time drought in northern China caused the Yellow River to dry up for a cumulative total of 333 days between 1990 and 1995. Weather-related problems in Europe, Asia, and North America cost the insurance industry more than $30 billion a year in the 1990s, more than 10 times the losses experienced in the prior decade.
It is not my intention to argue that the anomalies in weather experienced recently should necessarily be considered a harbinger of what we may expect in the future. But they do emphasize our vulnerability to unexpected changes in climate and the need for caution. At great expense, we have built roads and bridges and human habitations relying on what weather did in the past as a guide to what it might do in the future. If the rules change, and we have no warning, we may find the experience uncomfortable. One could argue that, given the uncertainties in our ability to predict, we should elect to live with the risk of future changes in climate. I prefer to ask whether we are justified in altering the composition of the atmosphere globally--and essentially permanently--when the changes we provoke may pose potentially serious risks for generations to come. Does not prudence dictate action now to buy time to evolve better tools for prediction in the future--especially if such action can be justified for reasons entirely independent of the threat to climate?
Examining American practice, it is clear that we are hooked on fossil fuel, like addicts dependent on cocaine. In 1995, 85 percent of primary energy consumed in the United States was supplied by fossil sources, compared to 8 percent from nuclear, 4 percent from hydro, and 3 percent from wood. We spent $60 billion to import oil, and perhaps as much again in military expenditures to ensure a stable and reliable supply. In real terms, we pay less for gasoline than at any time since the invention of the automobile--less than half what European and Japanese consumers pay. We take cheap fossil energy as a birthright, failing to appreciate the vulnerability it implies, despite the shocks to our economy imposed by the oil crises of the 1970s.
A broadly based tax on American fossil-energy consumption--ideally a tax on the carbon content of the fuel, introduced gradually to minimize economic dislocations and provide incentives for conservation and innovation--would allow us to reduce emissions of carbon dioxide. As far as possible, the tax should be revenue-neutral: funds raised should be used to compensate those most heavily affected by the tax (coal miners, for example) and to reduce existing tax burdens on capital and labor. It could breathe life into the market for nuclear power and for renewable forms of energy such as wind power, geothermal, and solar. In 1994, more than 600 megawatts of wind-generated electricity came on line worldwide, enough to power a city the size of Cambridge, but only 7 percent of this capacity was installed in the United States; the largest increases were in Germany, India, and the United Kingdom. Paradoxically, U.S. capacity actually declined in 1995, when Southern California Edison, citing lower costs for power generated with fossil energy, agreed to pay an independent generating company not to produce 420 megawatts of electricity with wind power for which it had earlier contracted.
|Ron McMillan-Gamma Liason|
Apart from obvious benefits for the environment, a tax on fossil fuel, by reducing our dependence on imported oil, could enhance national security and improve our balance of payments. By basing its negotiating stance in Kyoto on development of a sensible national energy strategy, the United States could simultaneously reduce its emissions of carbon dioxide and improve its economic and security prospects. A broad consensus among economists suggests that a carbon tax could be implemented without serious damage to the economy. Studies indicating the contrary generally fail to account for benefits accruing from reinvestment of related revenues, savings in terms of environmental damage averted, and opportunities for growth in other areas of the economy stimulated by higher prices for fossil fuel.
while the need for american action is clear, there is an even more urgent demand for an integrated energy-environment policy in China. A second industrial revolution is under way there today. In contrast to the first, which proceeded at a leisurely pace and involved at most a few tens of millions of people, this latter-day reenactment is running at breakneck speed carrying along more than a billion participants. China has little room to maneuver. It must deal simultaneously with problems of polluted air and water, with the need to feed, clothe, and advance the economic interests of its people, and now, additionally, with threats posed by prospects for an unexpected shift in climate in a region already subject to extremes of drought and flooding.
I saw the problem firsthand and had a clear sense of the complex choices facing the Chinese government when I visited the city of Chongqing a few years ago. I expressed a wish to visit one of the notorious Mao-era, coal-fired power plants and my Chinese host, a senior official from the National Environmental Protection Agency, readily acceded to my request. It was a scene from hell: an ear-piercing roar of air rushing at close to sonic speed up a high stack near the center of the complex; dirty yellow smoke casting a sulfurous acid pall over a city of more than 10 million people. The plant was in clear violation of China's admirable laws for environmental protection. As my host explained, they had few options for action. They could fine the plant, but it was already in the red and couldn't afford to pay, or they could close it down, and the city would run out of electricity.
Beyond the local effects on the Chinese people, we have a selfish interest in China's success in overcoming environmental stresses from industrial growth: in an interconnected world, atmospheric pollution problems are no longer contained by national borders. Pollution emanating from the Asian landmass is detectable in Hawaii. Moreover, apart from the opportunity to contribute to the protection of our own environmental infrastructure, there are rewards for our participation in helping China address its environmental needs: new markets for reinvigorated U.S. energy and environmental industries.
It is a challenge we cannot afford to forgo--but China must cooperate. Agreements reached at Kyoto should involve obligations not only for the industrialized world but also for large developing nations such as China. Commitments need not be identical--it is appropriate that they should recognize differences in stages of national development as well as discrepancies in current rates of per capita consumption--but they should be explicit.
All of which brings us, finally, to the crucial question of will. The world looks to the United States for leadership in Kyoto. I am optimistic that we will meet the challenge, but mindful also of the political realities. Democrats lost control of Congress in 1994 in part as a result of the Clinton administration's proposal of a relatively modest tax on energy. Vice President Al Gore '69 posed the problem well in Earth in the Balance: "The time has long since come to take more political risks--and endure much more political criticism--by proposing tougher, more effective solutions and fighting hard for their enactment." A worthy standard. We look forward to the outcome.
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