CLIMATE CHANGE

In recent years many environmental problems have come to public consciousness. Of all of these problems, global climate change could prove to be the most dramatic and least reversible. It could have profound implications for the health of humans and other beings.

A climate change is quite different from a change in the weather. While weather constantly changes, climate is relatively stable. One can discuss the North American climate during the last ice age, but when one talks about the cold and snow in Boulder, Colorado, yesterday, they are talking about the weather. Weather systems last from a few hours to a few weeks and range from about 10 to 10, 000 horizontal kilometers in size. A climate regime may persist for millennia, with variability in temperature and precipitation being part of a stable climate system. The climate system involves complex interactions between the atmosphere, oceans, land surface, snow and ice cover, and the biosphere. Researchers are learning that human activity is also a part of the dynamic that affects climate.

The Discovery of Anthropogenic Climate Change

On June 23, 1988, a sweltering day in Washington, D.C., in the middle of a severe drought in the United States, James Hansen of the National Aeronautics and Space Administration (NASA) testified before the U.S. Senate Committee on Energy and Natural Resources. It was 99 percent probable, Hansen contended, that global warming had begun. His testimony, which was covered by media all over the world, appeared to many people to come from nowhere. But like most overnight sensations, speculation about climate change has a history.

In the eighteenth century Benjamin Franklin surmised that the hard winter of 1783 to 1784 was due to excessive dust in the air, either from the destruction of meteorites or from volcanic eruptions. Early in the nineteenth century the French mathematician Jean Baptiste Fourier (1768–1830) speculated that the atmosphere might function like the glass in a greenhouse, warming Earth's surface by preventing heat from escaping. In 1861 British physicist John Tyndall (1820–1893) showed that slight changes in the composition of the atmosphere could significantly raise Earth's temperature. The Swedish Nobel Prize winner Svante Arrhenius (1859–1927) theorized in 1896 that the use of fossil fuels would increase atmospheric carbon dioxide, thereby changing climate and affecting biological processes. He calculated that a doubling of atmospheric carbon dioxide would lead to an increase of four to six degrees centigrade in Earth's mean surface temperature. In the 1930s the British engineer George Callendar revived Arrhenius's ideas and asserted that global warming had already begun. Working in the United States, Gilbert Plass, Roger Revelle, and Hans Suess brought these ideas into the scientific mainstream in the 1950s. A very influential article by Revelle and Suess in 1957 asserted that because of the exponentially increasing use of fossil fuels, an experiment was in progress that could not have happened in the past and that could not be reproduced in the future. Their work led to the establishment of the Mauna Loa Observatory in Hawaii, which has been measuring carbon dioxide concentrations in the atmosphere since 1958.

The climate anomalies of 1972 and the global food shortages of 1972 to 1973 brought the possibility of climate change to the attention of a broader audience. Droughts in the Sahel region of Africa in the late 1960s and early 1970s had reminded people how dependent on climate humans remain. When drought also occurred in the Soviet Union in 1972, world grain prices doubled and global food shortages followed. During the same year, frost destroyed coffee plantations in Brazil, and changes in seawater temperatures (related to a climate anomaly called El Niño) had a severe impact on Peru's anchovy fisheries. U.S. Secretary of State Henry Kissinger raised the possibility of climate change in a 1974 speech to the United Nations.

The climate change scare of the early 1970s was a fear of cooling. From the 1940s through the 1960s, Earth's mean surface temperature had declined; there was concern that another ice age was beginning. The Central Intelligence Agency undertook a study of how such a cooling might affect agricultural production in the Soviet Union; and the same Senate committee that fifteen years later would hold hearings on global warming held hearings on global cooling.

Whether the fear was of a cooling or a warming, climate increasingly came to be viewed as a dynamic system that is vulnerable to human action. By the mid-1970s the possibility of climate change had been discovered.

The Current Scientific View

Throughout the late 1970s and 1980s, conferences and studies were instituted by a wide range of national and international organizations. The culmination of this activity was the 1990 report of the Intergovernmental Panel on Climate Change (IPCC). The process that led to the development of this report involved 170 scientists from 25 countries; 200 other scientists reviewed the results. The goal of the IPCC process was to determine the international scientific consensus about climate change. The conclusion was that if emissions of greenhouse gases (primarily carbon dioxide, methane, chlorofluorocarbons, and nitrous oxide) continue as usual, Earth's mean surface temperature could rise 0.2 to 0.5 degree centigrade per decade, with a likely warming of 1 degree centigrade by 2025, and 3 degrees centigrade by the end of the twenty-first century. This would be the greatest temperature change to have occurred on Earth for at least 10, 000 years.

The eight warmest years in the historical record have occurred since the publication of the first IPCC report in1990. This, combined with scientific advances in the understanding of climate and increasingly sophisticated climate models, has strengthened the case for anthropogenic climate change. This has been reflected in subsequent IPCC reports. The 1995 Second Assessment concluded that "[t]he balance of evidence suggests a discernible human influence on global climate" (p. 5). The Third Assessment, published in 2001, stated categorically that "[a]nthropogenic climate change will persist for many centuries, " estimating that the Earth's global mean surface temperature will increase from 1.4 to5.8°C from 1990 to 2100 (p.17).

Although some remain skeptical, one thing that is certain is that there is a greenhouse effect. According to climatologist Stephen Schneider, it is "one of the best, most well-established scientific theories in the atmospheric sciences" (Boyle and Ardill, p. 12). Were it not for the greenhouse effect, all of the planets of the solar system would be cold and lifeless. But as researchers have learned in other areas, such as medicine, too much of a good thing can be a bad thing.

The greenhouse effect occurs when a planetary atmosphere, due to its physical/chemical composition, permits solar radiation to heat the surface of the planet but traps some of the heat that would otherwise radiate back into space. The greenhouse effect explains, at least partially, the differences between conditions on the surfaces of Venus, Mars, and Earth. Venus has an extremely dense, carbon dioxide-rich atmosphere that traps so much heat that life is not possible on the surface of the planet. Mars has a very thin, carbon dioxide–poor atmosphere, and mid-latitude surface temperatures on Mars are about the same as those of Earth's polar winters. Earth is just right for evolving and sustaining life—at least for the moment.

Another fact about which researchers are certain is that human activity is affecting the chemical composition of Earth's atmosphere. From 1860 to 2000 there was an increase of about 34 percent in atmospheric carbon dioxide, more than half of that occurring since the 1960s. Other greenhouse gases have increased by even greater percentages during the same period. Concentrations of these gases have risen as a result of activities that are essential to economic growth and development, at least as they are presently conceived: fossil fuel combustion, deforestation, food-animal production, rice-paddy agriculture, and fertilizer use.

What is certain, then, is that the greenhouse effect exists, and that concentrations of greenhouse gases in the atmosphere are increasing. However, not all scientists agree about the likely effects of these increasing concentrations. There are extremely complicated and ill-understood feedbacks in the climate system. The effects of these feedbacks could be to stabilize climate even in the face of changes in the atmosphere, or to exaggerate the effects of climate change. Since these feedbacks are not well understood, the scientific community's prediction of a significant greenhouse warming is a cautious one.

The Effects of Climate Change

The image that many people have of a global warming is that all regions of Earth would be warmed equally, as if one turned up the thermostat in the global house. This image is quite misleading. The impacts of global warming would be very diverse. Some regions would warm while others would cool. Precipitation patterns would change, and extreme events (e.g., droughts and hurricanes) would become more frequent. While this much is clear, it is extremely difficult to say how particular regions would be affected. The predictions generally agree about the global effects of climate change but disagree to a great extent about its regional effects.

Impacts of climate change fall into three categories. First-order impacts involve physical changes such as rises in sea level, effects on biological systems and circulation of water and so on. A large number of species will become extinct and many ecosystems will fracture and disintegrate. Some of the most dramatic first-order effects of a global warming would be the inundation of island nations, such as the Maldives, Kiribati (Gilbert Islands), and the Marshall Islands. Egypt could lose 1 percent of its land due to flooding. Second-order impacts involve the direct social, economic, and health effects of first-order impacts. An example would be the economic, social, and cultural consequences of Egypt's loss of 1 percent of its land. The part of Egypt that would be threatened by a sea-level rise is the Nile delta, home to 48 million people and contributor of 15 percent of Egypt's GNP. Third-order impacts of climate change involve the indirect social and political responses to the first-and second-order effects. Third-order impacts might include massive emigration from affected regions such as the Nile delta, and international conflicts resulting from economic dislocations and changing patterns of resource use.

The impact of climate change on human health is an area of research that has been receiving a great deal of attention. In particular, there is concern that infectious diseases such as malaria and dengue fever will become more prevalent, along with water-borne diseases such as cholera. There are already 300 million clinically confirmed cases of malaria in the world, causing more than 1 million annual deaths. Infectious diseases are currently the largest source of mortality in the developing world, and until sometime in the twentieth century they were also the largest killer in most of the developed world. Increases in the prevalence of infectious disease could have devastating effects on the human population.

Until the late 1980s it was commonly said that all people would suffer from climate change. However it has become increasingly clear that climate change will involve winners and losers, and most experts believe that the rich countries will do better than the poor ones. Rich countries can build seawalls and dikes to protect coastal areas against rising sea levels. They can even gain economically by developing and exporting technologies that will help in adapting to climate change. Rich countries can pay more for food if climate change adversely affects agriculture. In general, their control of capital can be used to shield them from many effects of a changing climate. Poor countries do not have resources to protect themselves in these ways. Moreover, some poor countries (e.g., Bangladesh) already suffer enormously from extreme climatic events.

But even though it may generally be true that the rich would do better than the poor in adapting to climate change, there are still reasons for the rich to be concerned. Rich people are often more averse to risk than poor people, for they have more to lose. Moreover, if climate change occurs, there will be differential effects across both rich and poor countries. For example, according to some scenarios, agriculture in the U.S. Great Plains might dry up and blow away, while in some arid regions of Africa precipitation might increase.

Although the regional effects of global climate change are uncertain, it is clear that there will be winners and losers. When human action has consequences that benefit some and burden others, it becomes a matter for moral evaluation.

Risk and Insurance

Some commentators have tried to transform the ethical problems implicit in the possibility of climate change into problems of rational choice. One approach has been to think of the possibility of climate change as a risk, and the costs of emission reduction, mitigation, and adaptation as the premium paid for insurance against this risk. However tempting this approach may be, the insurance metaphor is misleading. An insurance company is able to set rational premiums because of actuarial tables that are based on the frequency with which compensable losses occur. But however strong the theoretical reasons are for thinking that climate change will occur, researchers have nothing like actuarial tables that tell them about the frequency of climate change when the atmosphere is loaded with greenhouse gases. Moreover, the idea that society is in a position to reasonably assess the potential damages of climate change is quite absurd. No one knows what all the economic and health effects of a greenhouse warming would be, much less how to attach meaningful economic values to the loss of many wild species and the destruction of societies and cultures. As a result, economists who work on climate change tend to focus on the more easily quantifiable costs of emissions reductions rather than on the damages that such investments might help society to avoid. While it is easy to talk about the importance of taking out insurance against the possibility of a greenhouse warming, at present there is no way to determine what it would be rational to pay for such insurance.

Finally, the insurance metaphor defers rather than evades the ethical questions. Even if one were able to determine a rational premium, the question of how the costs should be distributed would remain. Talk of purchasing insurance against the risk of a greenhouse warming does not free society from the hard ethical discussions.

Moral and Political Issues

Philosophers often distinguish duties of justice from other sorts of duties. For present purposes, however, one can think of climate change as posing questions of justice with respect to human contemporaries (intragenerational justice), descendants (intergenerational justice), and possibly nonhuman nature. Because climate change is by its very nature global in scope, the questions of justice that it provokes are international.

The rich countries of the world have loaded the atmosphere with the greenhouse gases that may already be changing climate. They have benefited from their actions by developing economically. While rich countries have gained the benefits, the deleterious effects of their emissions will be felt by everyone. If climate change-induced floods occur in Bangladesh, it will not be due to the actions of the Bangladeshis. They will not have caused the floods, nor will they have benefited from the past emissions of greenhouse gases that caused them.

In addition to these historical inequities in emissions, there are important differences in present emissions. A handful of industrial countries emit between one-half and three-quarters of all greenhouse gases. Yet at the United Nations-sponsored Conference on Environment and Development, held in Rio de Janeiro in June 1992, the rich countries were unwilling to agree to timetables and targets even for stabilizing their emissions, much less reducing them, mainly due to the intransigence of the United States. Finally at Kyoto in 1997 the nations of the world did agree to binding timetables and targets for emissions reductions, only to have the United States and Australia jump ship after doing everything they could to weaken the agreement.

Rich countries became rich in part by taking actions that are changing the global climate. This climate change may have devastating impacts on poor countries. What do the rich owe the poor as a consequence of their actions? This question arises against the background of an international system characterized by radical and increasing inequality. According to Sir Crispin Tickell, in 1880 the ratio of real per capita income between Europe, on the one hand, and India and China, on the other, was two to one; in 1965 it was forty to one; and in the 1990s it was seventy to one. Even on the most conservative assumptions, between 1820 and 1970 global inequality doubled (Dollar and Kraay). One way of making this inequality vivid is by considering these examples from the Human Development Report 1998: Consumption for Human Development (United Nations Development Programme, p. 29). In 1960, 20 percent of the world's people who lived in the richest countries had thirty times the income of the poorest 20 percent, and by 1995 eighty-two times as much income. The wealth of the fifteen richest people in the world exceeds the total GDP of sub-Saharan Africa. The assets of the eighty-four richest individuals in the world are greater than the GDP of China at the beginning of the twenty-first century. The 225 richest people in the world have combined wealth that is equal to the annual income of the poorest 47 percent of the world's population. In absolute terms, more than 1 billion people live on less than $1 per day, and nearly 3 billion live on less than $2 per day (World Bank).

Underlying these problems of inequality and poverty are an exploding population in some parts of the developing world and increasing overconsumption in the developed world. The United States, with 5 percent of the world's population, annually consumes 25 percent of the world's fossil fuels, 33 percent of its paper, 24 percent of its aluminum, and 13 percent of its fertilizer. A child born in 1994 in the United States will in his or her lifetime drive 700, 000 miles, using 28, 000 gallons of gasoline; produce 110, 250 pounds of trash; eat 8, 486 pounds of red meat; and consume enough electricity to burn 16, 610 pounds of coal. Earth simply cannot support many Americans. The world population as of 2003 is more than 6.2 billion, and is increasing by 75 million per year. An optimistic scenario calls for world population to stabilize at more than 10 billion in the twenty-third century. Many observers expect population to grow far beyond that.

One way of trying to understand the joint impact of overconsumption and exploding population is to consider the following facts. Sweden is a country that enjoys one of the highest standards of living in the world, yet its per capita carbon dioxide emissions are little more than one-fourth of those of the United States. If Sweden's level of per capita emissions were to be established as an international ceiling, the United States would have to reduce its emissions by vastly more than anyone is willing to even consider. Yet, even given such painful reductions on the part of some countries, on this scenario world emissions would increase by more than one-third, reflecting the large populations of some less developed countries that consume very little energy.

Philosophical theorizing about international justice is underdeveloped, and very little work has been done on international environmental justice. The most influential philosophical theories of justice were formulated with an eye to what constitutes a just national distribution of private goods. Pattern theories such as that of John Rawls, and entitlement theories such as that of Robert Nozick, have received the most attention. Although one can speculate about what these theories might imply with respect to climate change, neither philosopher has had much to say about global justice, much less global environmental justice.

Rawls' principle of distributive justice is the "Difference Principle": Social and economic inequalities are to be attached to positions and offices that are open to all under conditions of fair equality of opportunity, and they are to be distributed to the greatest benefit of the least advantaged members of society. Whether one takes the subjects to be individuals or societies, it seems quite obvious that the global distribution of social and economic benefits is unjust according to this principle. Moreover, if one were to use the Difference Principle as a test for who should benefit from further releases of greenhouse gases and who should bear the costs of reduction, it seems equally clear that current policies would not satisfy this principle.

Nozick argues that the moral acceptability of a distribution depends entirely on how it came about. If the present distribution resulted from a just initial distribution through voluntary exchanges, then it is just, regardless of how unequal it may be. But given the global history of domination, imperialism, and exploitation, it seems clear that the present global distribution is unjust on Nozick's grounds. According to Nozick, any complete theory of justice must include a principle specifying how past injustices are to be rectified, but he has little to say about what such a principle may require.

Although it appears that both Rawls and Nozick are committed to the view that the current international order is unjust, neither deals specifically with this question or with the distribution of environmental benefits and burdens. Moreover, there are reasons for supposing that many environmental goods resist treatment as distributable benefits and burdens. The bad effects of climate change would include spillover effects suffered by some parties who had virtually no role in bringing them about. On reasonable human time scales, a stable climate is irreplaceable and irreversible. Furthermore, modeling aspects of the environment as distributable goods may be misleading and inappropriate. Such an approach neglects the fact that humans are situated in an environment that conditions and affects everything they do, and in part constitutes their identities.

While there is good reason for supposing that both historical and current patterns of greenhouse gas emissions are part of an unjust system of intragenerational relationships, philosophical theories of justice have not yet given the conceptual resources to address these issues in a detailed and meaningful way. More work needs to be done.

In addition to questions about intragenerational justice, global climate change poses moral questions about inter-generational justice. Those who come after us will live in a very different world than the one we inhabit in the early twenty-first century, due in part to actions that we are taking. Some who are influenced by utilitarian philosophers such as Henry Sidgwick may think that we owe just as much to future people as to present ones, since once they come to exist, they will be just as real as present people and will have the same moral status. On this view, the claims of future people should not be treated less seriously than those of present people simply because they are remote from us in time. But barring a complete collapse of Earth's human population, over the course of millennia there will be vastly more people in the future than exist now. If we take each future person as seriously as each present person, it would appear that the interests of the present would be swamped by virtue of the size of our future human population.

Other thinkers, impressed by an argument in Derek Parfit's 1984 book titled Reasons and Persons , may conclude that we have no obligations to future people (although this is not Parfit's conclusion). On this view, future people who feel disadvantaged would have no cause for complaint against us because their very existence would be contingent on actions that we have taken. If our present actions were other than they are, then different people would come to exist in the future. Thus, no future person can say that he or she would have been better off had we made different choices; for if we had made different choices, then that person would not have existed at all.

Many economists would grant that we have obligations to those who will follow us, but they would argue that these obligations are easily fulfilled. Suppose that, because in 2003 we act in such a way as to change the climate, our descendants living in 2103 incur damages valued at N dollars. In order for our climate change activities to be justified, we must profit enough from them to provide our descendants with N dollars when they come into existence. Because of the power of compound interest, small present benefits justify large future damages. If N dollars come due in a century and we can obtain a 5 percent return on our investments, our present benefit from climate-changing activities would have to be only .0068 N dollars (compounded monthly) in order for them to be justified. In other words, a present benefit of $100, 000 would justify inflicting a compensation of $14.68 billion on those living a century hence.

There are many problems with such an approach. Even if we were able to compensate future people adequately in this way, they will have been deprived of the ability to make some significant choices. For example, they will not have been able to choose to preserve a stable climate regime, even if that implies a lower standard of living.

This approach also involves the ludicrous idea that we can attach meaningful economic values to the loss of many wild species, the destruction of societies and cultures, and the unknown health effects of significant climate change. There simply are no credible attempts to carry out a benefit-cost analysis of the warming of Earth's median surface temperature by 3 degrees centigrade. This is hardly surprising, since there is often a great deal of disagreement about such relatively simple questions as the short-term effects of a change in the marginal tax rate of a single country.

Peter Brown and Edith Brown Weiss have argued that we have a fiduciary trust to preserve Earth's natural and human heritage at a level at least as good as that we received. On this basis, Weiss argues that we should reduce greenhouse gas emissions, take steps to minimize the damage that results from climate change, and develop strategies to assist future generations in adapting to climate change. This is a sensible approach that has the virtue of squaring with many people's moral intuitions. It suggests that we have significant obligations to future people, but that they do not entirely swamp the interests of the present.

Unfortunately, the fiduciary view verges on the platitudinous. Among those who believe that the buildup of greenhouse gases poses a threat, not many would deny that we need to reduce emissions, minimize harms, and develop adaptation strategies. What people disagree about is how aggressively we should pursue these policies, what the proper mix of them is, and who should bear the burdens. The fiduciary approach stops short of trying to answer these hard questions.

Furthermore, if we take seriously the idea that each generation has an obligation to preserve Earth's natural and human heritage at a level at least as good as what was received, then we are immediately faced with questions about how to evaluate the goodness of our own heritage and various changes that we might make with respect to it. These are the sorts of questions that economists try to answer, using various techniques of benefit-cost analysis, such as interviewing people about their willingness to pay (or accept compensation) for environmental good, that ethicists typically find unsatisfactory.

In addition to the problems of human health and welfare that are likely to be caused by climate change, nonhuman nature will also be affected. Climate change is likely to be much too rapid for most plants and animals to adapt to or migrate from. Even when migration would in principle be possible, no migration routes will be available for most plants and animals in a densely populated and developed world.

In recent years a powerful literature has developed that argues humans have obligations to nonhuman nature. Some philosophers, such as Peter Singer, argue that our direct obligations end at the border of sentience; others, such as Holmes Rolston III, argue that we have obligations to virtually every element of the natural order. Whatever we may think about this dispute, only someone who believes that our obligations are exhausted by our duties to humanity can remain unmoved in the face of this anticipated destruction of nonhuman nature.

Indeed, even someone who believes that our obligations are only to humans may feel that massive destruction of nonhuman nature is morally appalling. Humans have preferences about what happens to nature, and insofar as nature's destruction is contrary to human preferences, this destruction can be morally condemned. Moreover, anyone can be morally appalled by the character of a culture that would so willingly destroy nature in order to preserve a way of life that is rooted in overconsumption. One might think of nature as being like a work of art. We may not think that works of art are the direct objects of moral concern, yet we may morally condemn those who would vandalize them—say by burning the contents of the Louvre in order to warm their houses by one or two extra degrees for a year or so.

Climate change poses serious threats to human health and welfare and raises questions about our global duties and our duties to nonhuman nature. As the concentration of greenhouse gases in the atmosphere continues to increase, the moral issue of climate change will grow in importance.

dale jamieson (1995)

revised by author

SEE ALSO: Agriculture and Biotechnology; Endangered Species and Biodiversity; Environmental Ethics; Environmental Health; Future Generations, Reproductive Technologies and Obligations to; Hazardous Wastes and Toxic Substances; Justice; Population Ethics; Sustainable Development

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