November/December 1997
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November/December 1997 |
by James P. Bruce
The answer to this question depends on many things. Environmental challenges shared by Canada and the United States will be shaped by trends in the economy, science, technology, the global environment and social attitudes.
Even so, we know that major forcing factors, such as population growth and the nature and amount of materials and energy used by each person, will drive many of the important trends. Examining these forcing factors can show how the air, water and ecosystems shared by our two countries might be affected.
Forcing Factors
Canada's population of 30 million is expected to grow to about 35 million by 2025. The U.S. population will likely grow from 263 million to about 330 million. Growing populations, especially in urban areas near the border, will likely take more water from shared basins and generate more transboundary water and air pollution.
North Americans have an enormous appetite for energy. Each person consumes the equivalent of seven to eight tonnes (eight to nine tons ) of oil per year. This diet is heavy on fossil fuels (84 percent), leaner on nuclear (seven percent) and hydropower (six percent), and deficient in other renewable sources (only three percent). From 1995-2020, energy use in Canada is projected to grow by 27 percent with a 30 percent increase in coal use. North America contributes one-quarter of global carbon dioxide emissions with only five percent of world population. Neither Canada nor the United States has yet adopted policies sufficiently strong to stabilize, let alone reduce fossil fuel emissions, although heads of both governments have made commitments to limit emissions.
North Americans are also champions at consuming materials and producing solid wastes. Since 1960, the amount of solid waste generated by each person in the United States has increased by 65 percent. Municipal solid waste alone is projected to grow from 179 million to 200 million tonnes (197 million to 220 million tons) from 1993-2000. Much of this will be deposited in landfill sites near the Canada-U.S. border. In Canada, federal and provincial environment ministries have set an ambitious target of reducing solid wastes by 50 percent.
Large-Scale Environmental Issues
Many future environmental challenges will not be new. Concern over contamination of wildlife and humans by toxic chemicals will likely remain high. Though we've managed to cut back on what we pour directly into our waters, toxic chemicals released in the past will continue to seep from harbor sediments, ooze from underground disposal sites, and cycle back and forth between the water and the air. The long range transport of toxic chemicals is a dominant source of pollution of some boundary waters. New research shows there may be more widespread health and ecosystem effects than we previously expected (see article on page 14).
The thinning of the ozone layer in the upper atmosphere, due mainly to man-made chlorofluorocarbons (CFCs) also will remain an issue in the next century. Many life forms depend on the ozone layer to block much of the sun's ultraviolet radiation from reaching the earth. Though we do not fully understand the impacts on aquatic ecosystems, research suggests that they may be seriously damaged. For example, the insect larvae and microscopic animals living in water are an important link in the food chain and are particularly vulnerable to ultraviolet rays. Present controls of ozone-depleting substances under amendments to the Montreal Protocol would bring atmospheric chlorine to below critical levels after 2040 and would restore the pre-CFC ozone layer only several decades later.
Another major global environmental concern is that human activities, particularly burning fossil fuels and reducing forest cover, have markedly increased atmospheric greenhouse gases since the beginning of the industrial revolution. In a generally warming climate, evaporation would increase, resulting in lowered water levels and increased water demand from within and outside of boundary and transboundary basins. The extent to which this might be offset by increased precipitation in some areas is uncertain. Another set of implications that is beginning to emerge from the research is the link between the buildup of greenhouse gases and extreme climatic events, such as severe storms, heavy rains, floods and longer drought periods.
While acid rain was addressed fairly vigorously in eastern Canada and the United States in the 1980s and 1990s, it remains a nagging problem. Some decrease in acid deposition has occurred in eastern Canada and the northeastern United States, but many water bodies have yet to show signs of improvement. For example, only 10 percent of lakes in Quebec and the Atlantic provinces showed reduced acidity by 1994. Continuing to reduce the acidifying emissions will require vigilance in monitoring efforts, greater attention to nitrogen oxide reductions and ensuring that present declining sulphur dioxide emission trends are not reversed by policy changes, especially those related to utilities and transportation.
Ground-level ozone and particulates remain an important transboundary air pollution problem. During high concentration smog episodes, about one-half of southern Ontario's ozone comes from the United States and a significant portion of New Hampshire and Vermont's problem is from Ontario.
On both sides of the border, downsizing of government agencies at the federal, state and provincial levels has been a hallmark of the 1990s. This has been driven both by ideological and fiscal factors. It is difficult to predict whether this trend will continue into the next millennium, but there are signs that the reductions may have leveled off. Indeed, in some cases, such as Environment Canada's one-third budget cut, it is difficult to see how further reductions can be made without abandoning long recognized roles and needs for government involvement.
Even if the pendulum begins to swing back toward more government activity, however, current reductions in the number of observation sites for measuring water levels and flows, water quality, ecosystem health, climate and air quality have weakened our ability to understand what is occurring around us. Similarly background air pollution monitoring sites in Canada have declined, probably to below levels critical to assessing transboundary pollution. For trend analysis and to determine causes and effects, these losses of essential data will haunt analysts of boundary issues for years to come.
Conclusion
The environmental challenges of the next century will be influenced by a number of developments, but a small number of forcing factors, such as population and consumption trends, are likely to drive the large-scale environmental issues. It is possible to explore the likely transboundary implications (see table), though we don't know precisely how they will play out.
Selected Transboundary Impacts
Water supply
Will be impacted by population trends, amount used per person and climate change. Climate change models suggest that lower summer and autumn flows in watersheds from the Great Lakes to the Rocky Mountains will increase competition for available supplies. Significant lowering of Great Lakes is probable, with adverse impacts on water quality.
Floods
Urbanization and land use changes in watersheds and increasing runoff rates will exacerbate floods. Climate change projections suggest more flood-producing episodes in addition to longer dry intervals.
Threats to aquatic ecosystems
Fish species diversity is threatened by toxic contaminants, invasions by non-native species, ozone layer depletion, increased sedimentation of spawning beds and loss of habitat from forestry, agriculture and urbanization of watersheds. Increased dredging for shipping in the Great Lakes, due to lower levels, could lead to increased releases of contaminants from bottom sediments.
Transboundary air pollution
Degrades air quality affecting health, and contaminates water and soils. Higher ground-level ozone concentrations could result from longer, more intense warm spells due to climate change.
Threats to coastal zones
Threats include over-exploitation of fisheries and other resources. Greater contamination may result from long-range airborne pollution.
Sommaire
Quels sont les défis environnementaux qui nous attendent au tournant du siècle ? La réponse à cette question dépend de plusieurs facteurs. Les défis environnementaux que se partageront le Canada et les États-Unis seront déterminés par les grandes tendances dans les domaines de l'économie, de la science, de la technologie, de l'environnement planétaire, des habitudes sociales, etc.
Or, nous savons que ces tendances seront à leur tour influencées par des « facteurs forçants », comme la croissance démographique et la quantité de biens et d'énergie consommée par chaque personne. En examinant de plus près ces facteurs forçants, on peut établir de quelle manière l'air, l'eau et les écosystèmes communs à nos deux pays pourraient être affectés.
L'accroissement des populations, notamment dans les régions urbaines et près de la frontière, entraînera sans doute une augmentation de la demande en eau de nos bassins communs et générera davantage de pollution de l'air et de l'eau de chaque côté de la frontière. Les Nord-Américains consomment énormément d'énergie. Toutefois, ni le Canada ni les États-Unis n'ont adopté de politiques pour rationaliser l'utilisation des combustibles fossiles. Les Nord-Américains remportent également la palme pour leur consommation de biens et leur production de déchets solides.
Parmi les défis environnementaux qui nous attendent, bon nombre font déjà partie de la réalité actuelle. Au cours du prochain siècle, on se préoccupera sans doute encore beaucoup des effets nocifs des produits toxiques sur les espèces sauvages et la santé humaine. L'amincissement de la couche d'ozone dans la haute atmosphère, dû surtout aux chlorofluorocarbures (CFC) liés à l'activité humaine, sera également au coeur des préoccupations. Un autre problème majeur à l'échelle planétaire est le fait que les activités humaines, notamment la combustion de combustibles fossiles et la réduction de la couverture forestière, ont augmenté la quantité de gaz à effet de serre dans l'atmosphère depuis la révolution industrielle. Bien que dans l'est du Canada et aux États-Unis on ait attaqué avec vigueur le problème des pluies acides dans les années 80 et 90, la situation n'est toujours pas réglée. Des deux côtés de la frontière, les années 90 ont été marquées par des réductions d'effectifs dans les organismes fédéraux, provinciaux et d'États. Bien qu'on ait noté une reprise des activités dans les milieux gouvernementaux, la perte de données essentielles sur les tendances sera lourde pour les analystes des questions frontalières dans les années à venir.
James P. Bruce lives in Ottawa and was recently appointed an Officer of the Order of Canada in recognition of four decades of distinguished public service. This includes developing a flood warning system for Ontario, first Director of the Canada Centre for Inland Waters, serving as assistant deputy minister of Environment Canada, helping to draft the Canada-U.S. Great Lakes Water Quality Agreement and leading scientific efforts to curb acid rain and human-induced climate change. He has also been named a fellow of the Royal Society of Canada and received the international prize of the World Meteorological Organization.
This article is based on a paper commissioned by the International Joint Commission; for the full text, contact an IJC office.
Revised: 24 December 1997
Maintained by Kevin McGunagle,
mcgunaglek@ijc.wincom.net