Secondary Environmental Indicators

The secondary environmental indicators discussed in this section are carbon dioxide, oil spills, pesticides, toxic releases, and wildlife. These often cited measures of the state of the environment are classed as secondary indicators in this report because, at best, they provide indirect information about environmental quality. In some cases, such as carbon dioxide, it is unclear whether the indicator contributes to an environmental problem, such as global warming. In other cases, wildlife for example, the questionable data makes it difficult to draw reliable conclusions.

Carbon dioxide emissions

Carbon dioxide (CO2) is a vital nutrient for plants. Oceans absorb and produce CO2 in great quantities through a complex cycle, and store about 50 times more carbon than does the atmosphere. The combustion of fossil fuels by humans also generates CO2.

Figures 41 and 42 are a graphic indication of how CO2 emissions correlate with fluctuations in Gross Domestic Product (GDP). American and Canadian CO2 emissions rose with economic growth until the 1970s. Emissions then leveled off before declining in the early 1980s. Recently, emissions have increased.

CO2 emissions have been linked to a possible human-induced global warming. As a result, controlling CO2 emissions has been the subject of many recent policy debates. In order fully to understand the popular global warming debate, one must appreciate the distinction between the greenhouse effect and the enhanced greenhouse effect. Scientists agree that there is a greenhouse effect that causes the earth to be warm. This effect occurs because greenhouse gases such as carbon dioxide, water vapour, nitrous oxide, and methane are transparent to the short wavelength radiation from the sun but opaque to the longer wavelength radiation emitted from the earth. In simple terms, greenhouse gases trap the heat from the sun and this warms the earth.

The popular debate revolves around the question whether humans, through their additions of greenhouse gases to the atmosphere, enhance the greenhouse effect that occurs naturally and, thus, contribute to global warming. The theory of enhanced greenhouse effect gained many advocates in the 1950s but lost popularity in the 1960s and 1970s when average temperatures fell. During the 1970s, the idea that pollution was causing global cooling by reflecting sunlight away from the earth's surface was supported by many who now promote the theory of the enhanced greenhouse effect.

Although some now claim that the increase in CO2 levels in the atmosphere will cause a catastrophic warming, there are many credible challenges to this theory. In the face of the uncertainty within the scientific community about the link between CO2 and global warming as well as the fact that, in the absence of a proven link to global warming, CO2 cannot be considered a pollutant but, at most, a secondary indicator of environmental quality.

The scientists who criticize global warming possess three powerful lines of attack on the apocalyptic theories: the inadequacy of the computer models being used to forecast future temperatures, the evidence from actual temperature records, and the strength of competing hypotheses (currently under-reported and insufficiently considered by policy makers) to explain warming.

The inadequacy of the computer models

It is important to realize that current projections of global warming and policy recommendations for dealing with the predicted crisis are based on computer models that try to forecast future temperatures based on a number of assumptions. At the present time, these computer models are incapable of modeling the atmospheric system completely. Large gaps in understanding about the way important variables such as oceans and clouds affect climate, and how the effects of these variables change with additions of CO2 make the predictions of these models unreliable.

In fact, the computer models cannot even replicate what has already happened to temperatures. For example, according to the model used by the Intergovernmental Panel on Climate Change (IPCC), the northern hemisphere should have warmed between 1.3o and 2.3o Celsius since the beginning of the century. It has not. For the northern hemisphere, the warming measured at ground-based stations is about 0.6 degrees Celsius--less than one-third the warming that was predicted to occur.

Evidence from temperature records

The second major criticism of the theory that temperatures are likely to rise as a result of increasing CO2 emissions and cause dramatic damage to the environment is that temperature records do not support a strong link between CO2 emissions and warming. According to ground-level temperature records, there has indeed been an increase in temperature over the past 100 years. Most of this increase, however, occurred before 1940; in other words, most of the increase in temperature occurred before the main input of human-induced CO2 emissions. In addition, records from the satellites that have been measuring temperatures in space since 1979 do not support the hypothesis that the earth is warming. While the climate models produced by computers predict that there should have been some warming over the past 18 years, the satellite data show a slight global cooling. Thus, the evidence does not support the predictions of the models. It is considered a problem in any scientific discipline when the evidence contradicts a theory, and such a discrepancy should lead to a re-evaluation of the models.

Other explanations for temperature change

There are other viable explanations that do not rely upon CO2 emissions to explain atmospheric temperature change. Unfortunately, these explanations have not received widespread media attention.

Some scientists hypothesize, for example, that much of the temperature fluctuation can be explained by changes in the brightness of the sun--something that is obviously beyond human control. Sallie Baliunas, a scientist at the Harvard Center for Astrophysics, explains:

Most of the warming early in this century, then, must
have been due to natural causes of climatic change,
and these natural causes must be understood in order to make an accurate assessment of the effect
upon climate of any human activities that may have
been added to the natural changes.

One possible natural cause of climatic change
is variation in the brightness of the sun. (Baliunas and
Soon: 81)

The processes of ``fingerprinting'' various mechanisms of climatic change and projecting climatic
change requires knowing all the relevant factors,
both those that are natural and those that are the result of human activity. And, these factors must be
considered simultaneously in a model. Once such a
model is verified, then only can each mechanism be
identified. Since the mechanisms of climatic change
are not fully known--as we have shown, the question
how the sun affects the climate is unresolved--and
the models have not been verified, fingerprinting is
not yet possible. (Baliunas and Soon: 86-7)

It is clear that a great deal of uncertainty surrounds the issue of climate change and many important questions remain unanswered. Are we experiencing a trend towards global warming? Do humans contribute to the trend through the emission of greenhouse gases? How significant is the human contribution? Would global warming cause widespread problems?

Some argue that we must take drastic regulatory action to control greenhouse gases without delay. However, because of the uncertainty and the unanswered questions, this is a simplistic approach to policy. In fact, we cannot afford to take action until we are reasonably certain that we have a problem because taking drastic measures to control greenhouse gases will come at the expense of other social objectives.

Oil spills

Oil spills are high profile events. Incidents such as the Santa Barbara oil spill of 1969 and the Exxon Valdez spill in 1989 receive intense media coverage. Despite the public perception that the number of oil spills and the severity of those spills has increased, figure 43 shows that there has been a declining trend in the amount of oil spilled in American waters over the last two decades. As a source of water pollution, oil spills from the petroleum industry are a minor source of pollution when compared to oil waste generated by households. It is estimated that American households pour 1.3 billion litres of oil and oil-based products down the drain every year (Allen 1993). In comparison, the Exxon Valdez spilled just over 41 million litres of crude oil into Prince William Sound.

While oil spills are never desirable, and the immediate damage can be alarming, in time nature will effectively deal with spilled oil. Since oil is a natural substance produced by the decomposition of micro-organisms, it degrades naturally in the environment. Within 48 hours of an accident, 40 percent of spilled oil evaporates. Bacteria and other marine species break down and consume over 90 percent of the remaining oil (Bast, Hill and Rue 1994: 148-53). In some cases, active cleanup can actually cause more harm than good. For example, the steam used to clean rocks kills many tiny organisms, including those that would otherwise ingest and decompose spilled oil.

Canadian data track total marine spills from petroleum, industrial waste, and other chemicals. Data are only available for the 10-year period from 1976 to 1987 (figure 44). Both the number of events and the volumes of oil spilled fluctuate widely during this period. This fluctuation can be attributed primarily to differences in the numbers of vessels involved in collisions, groundings, and sinkings. It is also due to changes in the number of accidents occurring when oil is being transferred from one vessel to another.

Pesticides

Pesticides are a family of substances including herbicides, insecticides, fungicides, and fumigants. Although DDT and several other notorious pesticides have been discontinued, pesticide use remains controversial. Figure 45 shows the use of pesticides per square kilometre of arable land in the United States and Canada. The limited data available show that, in the United States, the use of pesticides fell from 204 kg/km2 in 1980 to 196 kg/km2 in 1993. In Canada, use of pesticides fell from 94 kg/km2 to 70.5 kg/km2 between 1985 and 1994. While these declines are not dramatic, they illustrate that fears of greatly increased pesticide use have not materialized. (For a summary, see Easterbrook 1995: 79 ff.)

Pesticides today are substantially changed from what they were when first introduced. Research has produced pesticides that have a much shorter half-life and are, therefore, less dangerous to human and animal health. In the 1960s, about one-half of all pesticides were chlorinated hydrocarbons such as Aldrin, Dieldrin, and DDT. These persist in the environment and tend to accumulate in animal tissue. Today, chlorinated hydrocarbons account for only about 5 percent of all pesticides (Hayward 1994). They have been replaced by a new class of pesticides that are effective in lower doses, less persistent, and have fewer environmental side-effects.

Although pesticides are hazardous chemicals that should be handled carefully, their use yields enormous benefits and the risk from residues is minor. Pesticides stimulate crop production so that less land is converted from wilderness to agricultural uses, and food costs are lower. Banning pesticides and other agricultural chemicals could increase the average household's food bill by as much as 12 percent per year (Knutson et al. 1990). The EPA's most conservative risk-assessment models attribute a maximum of about 0.00008 percent of all cancer cases per year to pesticide residues (Utt 1991). In fact, the risk from carcinogenic compounds that occur naturally in food is much greater than the risk from pesticide residues (Ames and Gold 1996).

Toxic releases

The Congress of the United States passed the Emergency Planning and Community Right-to-Know Act in 1986 after the toxic catastrophe in Bhopal, India and a near disaster in West Virginia shortly after. This act stipulated that the compile the Toxic Release Inventory (TRI), which requires industrial facilities to report a broad range of toxic emissions. In 1993, the latest year for which data are available, the TRI program required the reporting of 316 chemical releases in 20 different categories. In Canada, time-series data do not exist over the same period, although the National Pollutant Release Inventory (NPRI) began a similar program in 1993. Figure 46 shows the data available for the United States and Canada.

In the United States, toxic releases declined sharply over the brief period for which data are available. Though this trend suggests an improvement in environmental quality, toxic releases are a problematic environmental indicator. Broad definitions apply to toxic wastes and the TRI does not distinguish between releases that pose environmental problems and those that do not. As the EPA points out:

TRI data alone cannot indicate the risk that chemical
releases pose to human health and the environment
... A determination of risk depends on many factors,
including the toxicity of the chemical, the extent of
exposure, the type of release, and the conditions of
the environment. For example, small releases of highly
toxic chemicals may present a greater risk than
large releases of less toxic chemicals. (USEPA 1995a)

Further, the TRI definition of ``releases'' makes no distinction between releases into the environment and instances where toxic wastes are disposed of in well contained enclosures. For example, though some chemical wastes are stored in secure underground facilities, the TRI program counts these underground disposals as toxic releases (Bast, Hill and Rue 1994: 148-53). In light of these problems with the data, the decline in releases may be a positive sign of environmental improvement but the magnitude of this improvement is difficult to measure.

Wildlife

The North American wildlife population consists of at least 1,950 species of vertebrates, 4,200 species of vascular plants, approximately 95,000 species of invertebrates, and 34,000 species of insects (Environment Canada 1991c: (6)4). Many more unrecorded species may exist.

The number of species officially designated as threatened or endangered by the United States Fish and Wildlife Service has almost quadrupled from 283 species in 1980 to 1125 in 1997 (figure 47). In Canada, the number of species designated by the Committee on the Status of Wildlife (COSEWIC) as extinct, extirpated, endangered, threatened, or vulnerable has increased from a total of 17 species in 1978 to 280 in 1996 (figure 48).

Although the number of species identified as endangered in the United States exceeds greatly the number identified in Canada, it is unclear whether this reflects any actual differences in the number of endangered species. These numbers may only reflect differences between the definitions in one country or the other of what constitutes an endangered species. In addition, definitions within each country have changed over time and now include more species. In the United States, for example, species are listed according to a process established by the Endangered Species Act (1973). The public originally supported the act on the grounds that it would protect animals such as the bald eagle and the grizzly bear. Today, however, more than one-half of the species listed are plants (figure 49), and the Fish and Wildlife Service has identified an additional 3,500 species as candidates for listing (Mann and Plummer 1992: 52).

In Canada, there are over 120 government and private programs that address wildlife issues (Environment Canada 1991c: (6)20-3). The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) is composed of federal, provincial, and territorial management agencies, the Canadian Nature Federation, the Canadian Wildlife Federation, and the World Wildlife Fund of Canada. Figure 50 shows the trends in species listings. Since 1986, plants have been the largest category of the species listed.

There are many problems in using wildlife as an indicator when assessing environmental quality. For example, the practice of relating the number of species that are becoming extinct to the amount of habitat destruction is a topic that is hotly disputed in the scientific community (Edwards 1995: 211-65). In addition, there is uncertainty associated with the classification of species as endangered and with the distinction between a species and a subspecies. Regardless of the answers to these scientific questions, private landowners are being forced to bear almost the entire burden of protecting listed species and habitat. In the United States, ``critical'' habitat is heavily regulated without compensation for the landowners, a practice that has already begun to erode political support for species and habitat protection.

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