Climate Change and Air Quality Assessment in Canadian National Parks

发布于:2021-10-23 15:55:46

Climate Change and Air Quality Assessment in Canadian National Parks

DAVID WELCH
Physical Sciences Advisor, Parks Canada 25 Eddy Street, 4th floor, Hull, Québec K1A 0M5, Canada

Key words: Abstract:

Climate change, air quality, air issues, national parks, threats, Canada At each national park in Canada, a panel of experts assessed threats to ecological integrity, and a park resource manager completed a structured questionnaire on air studies, air issues, local air pollution and air quality related values. These surveys, the general literature, and the findings of a Canada/US park air issues workshop give an overview of the issues facing national parks. Seasonal average temperature and precipitation values generated by four global circulation models under a doubling scenario were interpolated for each park. 1994-1996 average annual wet sulphate and nitrogen deposition and precipitation pH were interpolated from the national air pollution monitoring system. These data place national parks within the context of continental scale climate change scenarios and national pollution levels. In Canada, the air issues threatening national park ecosystems are, in order of importance, 1) acidification, 2) climate change, 3) toxics, especially persistent organochlorines, 4) UV-B, 5) the interacting and cumulative effects of several air issues, 6) enrichment from airborne nitrates and increases and 7) ground level ozone. The air issues affecting park visitors are 1) particulate matter, 2) ground level ozone, 3) UV-B, 4) noise from aircraft and traffic, and 5) light from towns obscuring the night sky. Canada’s boreal and Arctic national parks are severely threatened by climate change due to the relatively high levels of warming predicted at higher latitudes, coupled with drought prone, fire dependent boreal forests or widespread permafrost in the Arctic and sub-Arctic, and wildlife dependent on particular snow and ice conditions. Despite recent reductions in Canada’s sulphate emissions, the national parks in south-eastern Canada remain at risk of acidification due to continued high levels of nitrate emissions from automobiles, and loss of buffering capacity in soils and lakes after decades of acidification.
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G. Visconti et al. (eds.), Global Change and Protected Areas, 97–107. ? 2001 Kluwer Academic Publishers. Printed in the Netherlands.

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1.

THREATS TO ECOLOGICAL INTEGRITY

Many of Canada’s 39 national parks inherit the legacies of prior occupation, such as town sites, fields, orchards forest plantations, and of decades of park management oriented to tourism facilities. Nonconforming uses may also continue under park establishment agreements. Examples include domestic wood cutting and subsistence hunting by native peoples. Many through roads and railways continue in use. All parks are subject to local, regional, continental and global stresses, such as urbanization, loss of habitats for wide ranging species, and a variety of threats like airborne toxics, regional haze and visibility impairment, global warming and stratospheric ozone depletion. Twenty-nine significant stresses to national parks’ ecological integrity have been identified (Fig.1, Table 1) [1,2]. A stressor is significant if it has a definite ecological impact, affects more than and is not diminishing over time. Stresses range in frequency from two parks reporting heavy metal pollution to 24 reporting stress from visitor and tourism facilities, and average three to four per park. The higher levels of amalgamation shown in Table 1 are of roughly equal frequency. Until the 1980s, park management practices allowed or even encouraged some town sites to expand, golf courses, ski runs and roads to be built, natural fire to be suppressed, predatory wildlife to be extirpated, and charismatic mammals and sport fish to be introduced. Since then, Parks Canada has started to turn the tide on some of the in situ stressors. It has begun to restore natural fire and has capped the development of park towns and roads. The future is less certain, however, for regional developments that destroy and fragment habitats of wide ranging species, i n c l u d i n g widespread logging, encroachment of agricultural livestock, urbanization and rural road building. Many of these regional problems impact through habitat destruction and fragmentation. Sometimes they are also responsible for pollution, the transmission of exotic species, and wildlife disturbance and mortality. If they are of local or regional origin, then regional actions and national policies can combat them. However, pollutants carried by air, and their effects upon climate, soil and water chemistry, wildlife health and reproduction, are continental and global scale phenomena and require international solutions. The balance of this paper addresses these air issues, their impacts on park values, and ways in which a park agency can help to solve the issues.

2.

EXAMPLES OF AIR ISSUES

Acid deposition. Like the rest of Atlantic Canada, Kejimkujik National

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Park receives the full brunt of acid precipitation blowing east from the major urban and industrial regions of North America. Its low pH levels decrease the reproductive success of brook trout, reduce angling success and contribute to the disappearance of Atlantic salmon. Reductions of fish biomass lead to decreased reproduction of loons. The leaching of minerals from wetlands causes fen plants like sedges and shrubs to be replaced by bog species such as Sphagnum and Kalmia [3]. Acid deposition in national parks is discussed in more detail below. Climate change scenarios for Canada feature more total precipitation, more Winter rain at the expense of snow, earlier Spring runoff, more intense and prolonged droughts, and increases in sea level [4]. Warmer temperatures will raise the summer snow line, so there will be accelerated loss of glaciers and permafrost in alpine and Arctic environments. Earlier Springs and more drought in Summer will increase the prevalence of wild fire, and many areas of Canada may change from boreal forest to grasslands and aspen parkland. Climate change and national parks is discussed in more detail below.

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Mercury is released from combustion and manufacturing processes, sewage treatment, exposed soils, and decomposing and burning vegetation. It is the only metal that can be liquid or gaseous an atmospheric temperatures and pressures, and so mixes easily with air and is transported globally. It combines easily with carbon and hydrogen compounds and bio accumulates. Its highest levels are in piscivorous birds, marine mammals and native people in remote rural or natural areas. Cape Breton Highlands National Park has the highest known concentration of mercury in lake water in Atlantic Canada [5]. Kejimkujik National Park has the highest known mercury levels in loons in North America, where it reduces nesting and hatching success. Organochlorines. Most organochlorine pesticides were banned two decades ago in developed countries, but are still in use around the world. They are easily transported in the atmosphere and fall with snow and rain. They evaporate less at colder temperatures and so concentrate at high latitudes and altitudes. Research at Bow Lake, Banff National Park, shows that toxaphene is taken up by some zooplankton and bio accumulates in trout at up to 10-20 times the concentration in other fish, and up to 1000 times the concentration in fish at low elevation lakes in the park [6]. In Point Pelee National Park DDT has been found at significant levels in sediments where it was once handled and stored. High DDT levels have been blamed for reducing frog populations in several parks and wildlife reserves along the northern edge of Lake Erie. Only five frog species remain at Point Pelee. Ozone forms when sunlight acts on nitrates a n d volatile organic compounds released mainly from internal combustion engines. It takes several hours to build in concentration, so levels are typically higher in downwind rural areas than in urban source regions. High ozone levels are dangerous to active children and people with respiratory problems. The Canadian health standard for the maximum acceptable one hour average for ozone is 82 parts per billion (ppb). From 1986 to 1993 this was exceeded at Kejimkujik National Park on 24 days [7]. In 1994, Fundy National Park recorded the highest mean concentration of ozone recorded that year in Canada, 36 ppb. Particulate. Some park visitors seek isolation in the back country, but for many a drive-in campground is home for the night, and an open fire is an essential part of their experience. Campfires produce smoke particles small enough to enter the respiratory tract, exacerbating pulmonary and cardiovascular diseases in sensitive people, the young and the elderly. In Jasper National Park, a study of smoke in the main campground measured total suspended particles (TSP) to determine whether they were above the

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During one October week, TSP peaked at and exceeded 120 on half the days, even though only 413 of 781 camping sites were occupied. A full campground might push the level over at which point the federal government is supposed to take immediate action to protect human health. Comment. Natural areas are often more exposed to air pollution than cities. Acid precipitation and ozone levels increase downwind from source areas, canopy plants cannot seek shade from UV-B, predators cannot stop themselves from ingesting mercury and organochlorines, and natural ecosystems will not adapted readily to climate change.

3.

A SURVEY OF AIR ISSUES

Air issues are air or airborne phenomena of unnatural origin that degrade the integrity of ecosystems or the enjoyment and health of visitors. They are enumerated in Table 2, a ranking that emerged from an air issues workshop [9], a literature review and a questionnaire sent to each national park. For example, while high levels of ozone damage leaf tissue on seasonal time scales, there is much less evidence of multi year harm to plant populations. Acid deposition, on the other hand, has been widely documented to cause forest productivity declines, increase the prevalence of tree diseases, and prevent reproduction of some fish species. High concentrations of ozone cause respiratory stress in active children and in adults with respiratory ailments.

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Particulate matter and ozone combine as smog, to impair the enjoyment of natural vistas by reducing visual range and scene contrast.

Air issue related values are the things put at risk by air issues. Abiotic examples include surface water regimes affected by climate change and soils saturated with nitrogen from pollutant, fertilizer and biogenic ammonia deposition. Biotic examples include fish species reproduction impaired by acidification and organisms that bioaccumulate toxic substances that affect their health and reproductive success. Cultural examples are limestone buildings and tombstones, and natural exposures bearing pictographs that may be corroded by acid rain. Human amenity values include vistas unimpaired by regional haze and recreational activities dependent upon some aspect of climate. Human health values include protection from melanomas caused by excessive UV-B and freedom from respiratory stress due to excessive ozone. Local pollution sources. Most air issues stem from regional, continental and global pollution related to manufacturing, urban transportation, domestic heating, air conditioning and agriculture. However, thirty parks have in situ or nearby air pollution sources. Most are insignificant, such as diesel electricity generators for small, remote communities, or smoke and odour from landfill sites. Some are significant but not common, like pesticides drifting in from adjacent forestry land. The leading local air pollution sources are commercial and visitors’ vehicles, agricultural pesticides, smelters, saw mills and refineries.

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4.

PARK INITIATIVES TO RESOLVE AIR ISSUES

Parks should work to improve air quality because they have 1) a legal obligation to take reasonable measures to safeguard the health of visitors, 2) a legal obligation to protect valued ecosystem components, 3) a moral duty to inform citizens about environmental issues that affect their health and enjoyment of protected areas, and 4) a policy duty to help meet international obligations concerning air quality. The direct contribution of park efforts to improve air quality is trivial on a global scale, but as hosts to millions of visitors, parks can play an important role in demonstrating best practices and broadcasting air issues and solutions. Here are some of Parks Canada’s initiatives in this respect. Smoke management. Natural fire is an important ecosystem process, and Parks Canada conducts prescribed burning to meet fire restoration goals. Because burning wild land fuels release large quantities of smoke, particularly during periods of high fuel moisture, smoke management is considered in planning burns. Therefore planned ignition prescribed fire is preferred over wildfire or lightning ignited prescribed fire, since the selection of appropriate fuel moisture and atmospheric conditions, ignition technique and pattern reduces the amount of smoke emitted. Green operations. Parks Canada is reducing the use of chemical pesticides by assessing the need to control unwanted organisms, and using alternative pest control methods. Energy conservation, reduction of air emissions, and the reduced use of ozone depleting substances are government priorities. Actions include minimizing the consumption of gasoline in favour of alternative fuels. Unfortunately, Parks Canada has no direct sway over the main sources of greenhouse gases emitted from within national parks, namely through traffic, railway operations and buses. A greater contribution to greenhouse gas emission reduction may come from educating visitors about air quality, global change and ecosystem responses, and demonstrating best practices. Campfires, ecosystem management and health risk. At campgrounds where firewood is free, wood consumption is about ten times greater than where it is purchased. In 1994 Kouchibouguac National Park switched from giving to selling firewood to visitors, a change that reduced the exposure of visitors to inhaling particulate matter and volatile organic compounds. During some periods without inversions, for example, Benzene (a) Pyrenees levels exceeded health standards. The park is monitoring vegetation around the campground to assess the impact of visitors who branches and woody debris for their recreational combustion. Northeast Regional Air Quality Committee. Parks Canada co-chairs the Northeast Regional Air Quality Committee, a partnership of federal, state

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and provincial protected area and air quality agencies in New England (USA) and Atlantic Canada. It exchanges information between member agencies, and provides a link between land management and air quality agencies across jurisdictions. The partners cooperate to understand air issues and document air quality improvements, increase public and employee understanding of the issues and opportunities, and develop support for air quality improvement goals from other agencies.

5.

FOCUS ON ACIDIFICATION

Precipitation pH and sulphate deposition for Canadian national parks east of 110°W and south of 60°N are shown in Table 3. All Canadian national parks for which pH can be interpolated with confidence have precipitation pH averages less than 5.3 (Riding Mountain) and as low as 4.35 (Saint Lawrence Islands), about 10 to 50 times more acid than should be the case. Clearly, acid rain, acid snow and acid fog continue in eastern Canada despite recent sulphate emission reductions. As well, recovery is stalled due to the loss of buffering capacity after decades of acidification [10], exacerbated by increasing nitrate emissions from the ever growing and more powerful North

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American vehicle fleet. The Canadian target load for wet sulphate deposition is 20 kg/ha/yr. However, many researchers consider this too high to protect sensitive forest ecosystems, and 8 kg/ha/yr has been proposed as a target. Calcareous soils can neutralize acid better than acidic soils, so the wet sulphate critical load for forest damage depends on soil type. The national parks of southern Ontario and La Mauricie suffer deposition around 20 kg/ha/yr, and it is not until one travels as far east as Terra Nova that loads fall below 8 kg/ha/yr. It is clear that in many eastern parks, sulphate deposition exceeds the critical load. The precipitation interpolations are corroborated by in situ surface water pH measurements in Atlantic parks. In 1994 the lowest surface water pH in Cape Breton Highlands was 4.6, Gros Morne 4.8, Kejimkujik 4.2 and Terra Nova 5.1. With a pH over 5.5 to 6 there is a good chance of maintaining aquatic biodiversity, but 75% of fish species are lost as pH declines to 5. Some sport fishes can be lost at pH of 5.6, while Atlantic salmon and brook trout are usually present until pH goes below 5.1. Among benthic macroinvertebrates, acid sensitive species include mayflies, caddisflies, stoneflies, amphipods, crayfish, snails, clams and leeches.

6.

FOCUS ON CLIMATE CHANGE

National park seasonal temperature and precipitation values for were interpolated from four general circulation models (GCMs), the Canadian Climate Centre’s GCM II (CCCII) and Coupled GCM I (CGCMI), Princeton University’s Geophysical Fluid Dynamics Laboratory model (GFDL), and NASA’s Goddard Institute for Space Studies model. The results show that 1) there will be warming, 2) there will be more warming during the winter, and 3) that this effect increases poleward [11]. What is striking about the interpolations is the extreme amount of winter warming expected for many parks, e.g. GISS showing +11.5°C for Aulavik, CCCII showing +8.0°C at Grasslands, and CGCMI showing +8.2°C in Wapusk. The models also reveal much variation at regional to local scales, even before micro and meso climatic phenomena are taken into account. Precipitation scenarios show a great range of dryer to wetter conditions. Aulavik and Tuktut Nogait, for example, might experience Winter precipitation from 20% dryer to 30% wetter, whereas Prince Edward Island may be wetter by 10% to 15%. Some consistencies emerge at regional scales. Most areas will be distinctly wetter in Winter. The same is true in Spring, but with more exceptions such as Ellesmere Island and Pacific Rim. Fall precipitation values reveal much greater

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uncertainty between models, the extreme being Point Pelee that could be as much as 35% dryer or 25% wetter. Summer scenarios are again more consistent, projecting an overall dryer climate in boreal and southerly areas and wetter in the Arctic. These data reflect the conclusions of the general literature, typically expressed as continental averages. They also underscore the great variations possible at regional to local scales and from season to season. Winters will be wetter but warmer, so that there will be more rain as opposed to snow, and so that the snow pack will form later and melt sooner. An earlier Spring, coupled with less snow to be melted, will reduce Spring flooding, although there may be more local storm related flood events. In many regions, the earlier and reduced snow melt will lead to dryer soil conditions for longer periods, even without considering the warming in Summer. We can expect chronic and occasional severe drought in Summer. Wind erosion will increase over the Great Lakes dune shorelines and the Prairies, especially at Point Pelee, Elk Island and Grasslands National Parks. In the Arctic, permafrost melting will accelerate and combine with runoff and ice melt to increase erosion.

7.

CONCLUSION

Acidification remains a significant threat to Canadian national parks everywhere east of Manitoba. It is the leading air issue, but toxics, climate change, ground level ozone and particulate matter are crowding in. There is a need for enforceable regulations to protect all ecosystems and species from these threats. Such measures are exemplified by the acid deposition critical load concept, secondary standards and regional rules to supplement point source emission controls. A common cause of many air quality and climate change problems is the burning of fossil fuels. Acid gases, acid aerosols, particulate matter, nitrates, carbon dioxide, volatile organic compounds and heavy metals are all released in abundance by this one basic process. While governments and industry can and do encourage, force and implement many changes to improve the picture, it will take societal shifts in lifestyles, consumption choices and urban design to achieve radical improvements in the global ecosystem.

8.

ACKNOWLEDGMENTS

Thanks to Bob Vet and Chul Un Ro, Environment Canada, for the acid deposition data, to Neil Munro, Parks Canada, for the surface water pH data,

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to Daniel Scott and Bonnie Hui, University of Waterloo, for climate change scenarios, and to numerous colleagues in Parks Canada and other protected area agencies in Canada and the United States for answering questionnaires, attending meetings and providing relevant park documents and data bases.

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REFERENCES

Bailey R. and A. Stendie, Should campgrounds have campfires? Research Links 1(1) (1993) Campbell L., Research Links 4(3) (1996) 11,6. Commission for Environmental Cooperation, Long range transport of ground level ozone and its precursors: assessment of methods to quantify transboundary transport within the northeastern United States and eastern Canada, Montréal, 1997. Environment Canada, Canada United States Air Quality Agreement 1998 Progress Report, Ottawa, Supplies and Services Canada, 1998. Environment Canada, Canada’s second national report on climate change, Environment Canada on-line document at http://www1.ec.gc.ca/climate/index.html, 1997. Hauge E. and D. Welch (Eds), International Air Issues Workshop, Waterton Lakes National Park 5-8 June 1995, United States National Park Service, publication no. NPS D-1116/May, 1996. Hengeveld H., Understanding atmospheric change: a survey of the background science and implications of climate change and ozone depletion, Supply and Services Canada, State of the Environment Report No.92-2, 1995. Kerekes J. et al, In: T.B. Herman et al, Ecosystem Monitoring and Protected Areas, Proceedings of the Second International Conference on Science and the Management of Protected Areas, Science and Management of Protected Areas Association, 1995, pp.326-331. Northeast States for Coordinated Air Use Management et al, Northeast States/Eastern Canadian Provinces Mercury Study, Boston, Massachusetts, on-line document at http://www.cciw.ca/eman, 1998. Parks Canada, State of the parks 1994 report, Ottawa, Canada, Supply and Services Canada, 1995. Parks Canada, State of the parks 1997 report, Ottawa, Canada, Supply and Services Canada, 1998.


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