CANADA: SPECIAL REPORT
Λ Iι
THE GLOBAL WARMING CHALLENGE Understanding and Coping with Climate Change in Canada /
anada is the world's sec ond largest c o u n t r y , with 10 million square kilometers of territory bounded by three oceans. Its large size and extensive coastlines ex pose the country to many different climate regimes, from the rain for ests of the west coast to the dry prai ries in the interior and the frozen expanses of the north (2). Years of experience in coping with these varied conditions have helped Ca nadians develop a social and eco nomic structure that is well adapted to the realities of their climate as we know it today. It is not surprising, therefore, that Canadians have a profound interest in climate change and, particularly, global warming. Global warming, for example, could improve the growing seasons for certain ecosys tems and destroy others with fire and drought. It could open up our ice-congested Arctic waters to in creased shipping and cause the col lapse of surface transportation sys tems over p e r m a n e n t l y frozen lands. The exact consequences of global warming are uncertain, of course, but one thing is clear: global warming will necessitate significant adjustments in Canadian society and its economy. A national climate program For decades, Canada has recog nized the importance of monitoring its diverse and variable climate. The nation maintains a central archive of climate data collected from a country-wide network of monitor ing stations at more than 2000 loca tions; some stations have been in
place since the mid-19th century. The resultant information, which builds understanding of the past be havior of climate, provides an impor tant basis both for designing our country's infrastructure and for plan ning our socioeconomic activities. Although knowledge of past pat terns has helped Canadians to in crease the compatibility of Canada's culture with its ambient climate, that focus alone is not enough. The 1970s brought a range of unusual weather events that woke the entire world to the importance of factoring climate variability into decision making. Episodes of extreme cold, droughts, floods, and other climateinduced hazards resulted in exten sive crop failures, food shortages, price inflation, and hunger in other parts of the world. In particular, these events raised questions about the reliability of using past climate as an indicator of future climate. Conferences sponsored by agencies of the United Nations began to focus on the causes and consequences of unusual climate events. Finally, in 1979, the First World Climate Con ference held in Geneva laid the groundwork for the establishment of the World Climate Programme. In the same year, the Canadian federal government created its own Canadian Climate Program (CCP) in collaboration with other agencies, institutions, and individuals. It
HENRY
HENGEVELD
Environment Canada Downsview, ON, Canada M3H 5T4
0013-936X/94/0927-519A$04.50/0 © 1994 American Chemical Society
sought to coordinate national efforts to understand global and regional climate, and to promote better use of the emerging knowledge. Its orig inal objectives, which remain rele vant today, were to: • develop the ability to predict cli mate and climate change; • assess the impact of human activ ities on climate; • improve the use of climate infor mation in Canada's economy; and • through the World Climate Pro gramme, assist developing coun tries in improving their use of cli mate information (2). The CCP is administered by a na tional Climate Program Board, which includes representatives from federal agencies, provincial governments, universities, and the private sector. A number of advi sory committees and subgroups as sist with program coordination, in c l u d i n g the N a t i o n a l Climate Advisory Committee on Data and Applications, the Research Advi sory Committee, and the Socio-Economic Impacts Committee. This collaboration between agencies and scientists is vital to the program. Climate change research Growing international concerns about global warming have high lighted the need to better under stand the global geophysical sys tem, i n c l u d i n g the processes governing the natural cycles of greenhouse gases and the global cli mate system. Hence climate system research and investigations into the fluxes of greenhouse gases between the atmosphere and the vast Cana dian terrestrial ecosystems and ad-
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Canadian GCM projections of seasonal climate warming under a doubling of atmospheric CQ 2
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Summer (June, July, Aug.) (Celsius degrees)
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jacent oceans have become key fostudies suggest that Canadian bocal points of the CCP. real forests provide a net sink for carbon dioxide, after allowing for Much of the CCP-coordinated reeffects of wildfires, insect-induced search into sources and sinks of mortality, and harvesting, of about greenhouse gases interfaces with 100 Mt of carbon per year. Investiother national and international programs. Many of the investigations into carbon fluxes in t h e oceans, for example, are conducted GLOBAL. within the framework of the international Joint Global Ocean Flux WARMING Study, which is aimed at understanding the role of the ocean in the WOULD global carbon cycle (3). Other researchers have become NECESSITATE involved in the Northern Wetlands Study, a cooperative United StatesSIGNIFICANT Canada initiative to understand the role of huge northern bogs and ADJUSTMENTS muskegs in the carbon cycle (4). Results from these studies show that IN CANADIAN net methane emissions from wetlands adjacent to Hudson Bay are an SOCIETY AND order of magnitude smaller than would be expected from previous esITS ECONOMY. timates based on studies in peat lands further south. Emissions were found to be highly sensitive to depth of water tables (5, 6). The low methane fluxes from northern wetlands are likely the result of ecosystem and physiological controls of methane production and consumption (7). Likewise, carbon fluxes in forests gators suggest this carbon sink exare a focus of current interdiscipliists primarily because these forests nary projects such as the Boreal Ecoare still in a process of aging and systems—Atmosphere Study and the hence increasing their store of Northern Biosphere Observation carbon within the standing biomass and Modelling Experiment. Prelimand litter. However, as the forests inary results from these and other mature, this sink will likely disap520 A
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pear. Furthermore, if warmer and possibly drier climates develop in the decades to come, as projected by climate model experiments, increased intensity and frequency of fire and insect disturbances could turn the boreal forests into a significant source of carbon dioxide [8). Modeling studies to explore climate—carbon cycle linkages are now in progress. Meanwhile, research programs within Canada's agricultural community include investigations into related g r e e n h o u s e sources and sinks from this sector. Results from Canadian studies into climate system processes have made similar contributions to understanding the Earth's climate system [9-12]. However, the challenge is formidable. The total global climate system involves not only a dynamic and chemically active atmosphere, but also circulating oceans, advancing and retreating ice sheets, and changing vegetation patterns. In real life, these components are coupled in an intricate and interactive manner that involves complex feedbacks. Researchers are still uncertain about how the various climate processes behave under stable climate conditions, let alone how they respond to large changes in one or more components. General circulation models Because of the need to understand how the whole, linked climate system works, climate model-
ing emerged as a key focus of current research. Within Canada, modeling began in earnest in the mid-1970s with the establishment of a small group of climate modelers within Environment Canada's Atmospheric Environment Service (AES). By the late 1980s, the AES group had developed a second-generation, high-resolution General Circulation Model (GCM) of the climate system. This model is now generally accepted as one of the world's more advanced models for assessing global climate change caused by an equilibrium response to a doubling of atmospheric carbon dioxide concentrations; that is, it illustrates how the Earth's climate might function once it has adjusted to a carbon dioxide doubling. The atmospheric modeling group is currently cooperating with oceanographers to develop a third-generation GCM with a fully coupled ocean—atmosphere climate system. This model will build on the successful foundation provided by the AES second-generation model by incorporating improvements to many of its present features while adding important new capabilities. Results of future experiments with this model will help provide new and unique insights into the international understanding of the role of various climate system feedbacks in amplifying or a t t e n u a t i n g change, and of the transient response of the total climate system to forces of change as they happen (13). Improvements being incorporated into the model include better understanding of how cloud processes affect climate; improved characterization of soil and vegetation properties at the atmosphere—land interface; and a more sophisticated treatment of processes taking place in the middle atmosphere (up to 85 km above the Earth's surface), particularly with respect to chemical interactions between trace gases and their effects on the Earth's radiative budget and atmospheric circulation. With the aid of Environment Canada's supercomputer in Victoria, these changes will allow more realistic simulations of the Earth's gradual response to slowly changing atmospheric conditions, including the effects of changing ocean circulation as a feedback to global warming. Researchers are also developing regional models that expand upon the output of the relatively low-resolution GCMs (2). These regional
models use the output of the global GCMs as inputs for the boundary conditions of the changing climate within the region, but can simulate local characteristics and small-scale processes of the climate within the region with much greater accuracy and detail. The results provide a description of the local characteristics of climate change that is more suitable for use in assessment of ecological and socioeconomic impacts, without being limited by inadequate computing power. However, the accuracy of results continues to be limited by uncertainties in the boundary conditions provided by the global GCMs. A substantial increase in central funding since 1991 has helped stimulate and focus this research nationally. To further support GCM modeling and conduct related research, Canada is now developing a joint university—government—industry Climate Research Network (2). Research groups across the country will each focus on a particular area, and a high-speed data link will connect the groups to each other and to the modeling group and its supercomputer. The network, with the GCM research as its focal point, contributes substantially to the international research effort, while providing Canada with a well-coordinated base of expertise for assessing the country's vulnerability to the risks of climate change and formulating appropriate policy responses. Key network research nodes will include ocean circulation modeling (Victoria and Montreal), a t m o s p h e r i c c h e m i s t r y (Toronto), clouds (Toronto), paleoclimate (Ottawa), land surface processes (Saskatoon), and regional climate modeling (Montreal). Preparing for climate change Applied climatology helps Canadians deal with the constraints imposed by local climate, while capitalizing on the opportunities that it provides. However, cultures in harmony with their climate can be more vulnerable to climate change; anticipation of change and preparation for it become extremely important. Unfortunately, it is still impossible to accurately forecast how climate will change. Prediction is especially uncertain for those climate characteristics of greatest importance in strategic planning, such as the rate at which changes will occur; the geographical patterns of changes in temperature and precip-
itation; and the frequencies of storms, droughts, severe hot or cold spells, and other extreme events. However, models that project how climate will respond to increasing greenhouse gas concentrations can already provide some clues. The models can indicate the direction such changes may take and can help test the sensitivity of ecosystems and socioeconomic activities to a range of possible changes. In the past decade, many studies have explored the impacts of past climate fluctuations and extreme events on Canadian ecosystems and society, and have helped to assess Canada's vulnerability to the effects of possible future changes [14, 15). The studies have involved a wide range of methods, ranging from simple empirical investigations into the consequences of a historical event to sophisticated analyses of the effect of a range of possible climate change scenarios ("what if" case studies) on integrated systems. Studies make extensive use of advanced models, developed from analysis of past experience, which describe the climate—ecosystemsociety linkages, including crop growth models, hydrological models, forest fire models, total ecosystem models, and models of socioeconomic response to change. Results of the studies, many of which are regularly summarized in the Climate Program Board's series of "Climate Change Digest" reports (26), are both encouraging and worrisome (see box). Many Canadian ecosystem processes and society activities are currently limited more by cold-temperature extremes than by warm extremes. Hence, many aspects of the impacts of warmer temperatures are potentially beneficial, providing Canadian ecosystems and society can adapt quickly enough. This is not valid, however, for systems that have long lifetimes and hence respond slowly to change (e.g., forest ecosystems), or for activities that depend on cold climates (e.g., winter sports and winter Arctic transportation). On the other hand, many of the implications of climate change impacts on water resources are problematic, particularly in the interior of Canada. In some cases, adaptation will be difficult, and major negative residual effects unavoidable. Earlier data are meaningful In 1991, the Climate Program Board's Socio-Economic Impacts Committee recommended that, in
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Projected changes in Canadian ecozones as a result of doubling of atmospheric CQ2 Present day I I Tundra I I Boreal Temperate I I Grassland I I Unclassified
addition to continued sectoral investigations into impacts of climate change and variability, integrated regional climate change impact studies be conducted in three key areas: the Great Lakes region, the Mackenzie Basin, and the Prairie Provinces (2). Such integrated studies would consider, in addition to the direct impacts of change on plant species and socioeconomic sectors, the role of intersectoral and ecosystem feedbacks and adaptation measures in altering the firstorder effects. The Mackenzie study, which focuses on Canada's largest river and surrounding basin (home to many of Canada's indigenous peoples), is now in its third year. Areas being investigated include the impacts of several climate change scenarios on water management, sustainability of native lifestyles, opportunities for economic development, buildings and infrastructure, ecosystem sustainability, and strategies for limiting greenhouse gas emissions. Within the project, some 30 specific studies are now under way, including analyses of forest and wetland response, treeline response, permafrost, fisheries, basin runoff, ice in the Peace River, fire and its impact on wildlife, agriculture, and tourism. The research makes use of a variety of resources, including remote sensing and traditional climate knowledge of indigenous people, and has already generated some 15 reports {34). While not as advanced in development, the other two regional studies already have a large volume 522 A
How Global Warming May Affect Canada If a doubling of atmospheric C 0 2 concentrations (or equivalent) causes global warming as projected by equilibrium climate models, then: • Average temperatures are likely to rise by 4 - 1 0 °C across most of Canada, with the largest increases in interior regions and in winter ( 14). • Interior regions of the country, including the very productive agricultural regions, appear likely to become drier, with southern river systems experiencing decreases in runoff of 2 5 - 5 0 % . Severe droughts can be expected to become more frequent in these regions, and water quality is likely to deteriorate significantly (17-21). • In those areas not affected by increased drought, an agricultural industry appropriately adapted to the changes is likely to benefit substantially from the warmer growing conditions and higher carbon dioxide concentrations. However, increased problems with pests and diseases is a concern, and poor northern soils will limit potential for northward expansion of agriculture (22, 23). ' Southern and dry zones of forest ecosystems are unlikely to adapt quickly enough to projected changes, and are likely to suffer increasing damage from pests, diseases, and fire (24, 25). • Warmer winters will greatly reduce space heating requirements and are likely to reduce snow removal and road maintenance budgets. However, winter recreational industries that depend on snow cover and lake ice could become untenable in the most densely populated regions of the country. Summer cooling costs are likely to rise (26, 27). ' Transportation in ice-covered waters will become easier and less costly. Land transportation and pipeline systems over permafrost regions and in areas dependent on frozen winter roads will experience increased land instability and costly maintenance, and may have to be abandoned in some regions (28-31). • Both freshwater and ocean fisheries will need to cope with changing fish habitats and migration or severe decline of critical fish species (32, 33).
of research results from past studies as a starting basis. An advisory board has been established to guide the development of the Great Lakes study, with the recommendation that the integrated study be focused on water management, ecosystem health, land use and management, and human health (35). The Prairie regional study is still in the early
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development stage, although work has started on a comprehensive history of drought frequency, dust storms, and related soil drifting. Future directions The improving scientific understanding of the climate system and of the sensitivity of ecosystems and society to change and variability
will, in time, give rise to new and important applications of climate information. For example, reliable seasonal and annual forecasts of cli mate conditions and related im pacts are a realistic possibility. In the future, advanced regional mod els coupled to improved GCMs are also likely to provide more reliable advance warnings of anomalous cli mate extremes and v a r i a t i o n s , whether as a consequence of slowly developing global warming or as a result of events such as El Nino or major volcanic eruptions. However, one of the most press ing demands for better understand ing of the climate system currently comes from the policy-making com munity seeking appropriate re sponse to the risks of future global warming. Policy makers have recog nized that, although the conse quences of potential global warm ing are as yet poorly understood, the threat is real. Canadian policy makers are now developing a na tional action program on climate change involving three distinct yet interactive components. The first will, as a precautionary measure, seek to stabilize the anthropogenic emissions of greenhouse gases at 1990 levels by the year 2000 and ex plore options for further reductions. The second component will pro mote measures within Canada to better adapt to current and future climate conditions, thus reducing the negative consequences and maximizing new opportunities pre sented by global warming through anticipatory actions. The third com ponent recognizes that improved scientific understanding is a critical aspect of appropriate future deci sions relating to the other two com ponents, and will seek to strengthen the Canadian scientific effort perti nent to many of the key policy ques tions. To ensure that it fully ad dresses the c o n c e r n s of all Canadians, the national action pro gram is being developed through a multistakeholder consultation pro cess involving various levels of gov ernments, academia, industry, envi ronmental groups, and the general public. A final draft of the program, now being developed by a representa tive task group, will undergo pub lic debate through regional work shops in the fall of 1994 and will be ready for government approval by March 1995. It promises to pro vide Canada with tough but fasci nating challenges during the de cade to come.
fes/S Henry Hengeveld is Environment Can ada's science advisor on climate change. During the past 12 years in this position, he has published numerous documents on the science of global warming for use by policy makers and the public, and he regularly briefs senior decision makers within the Canadian government on new related scientific developments. He has frequently partic ipated as a member of Canadian delega tions to international meetings on scien tific assessment of global warming and related negotiations of a climate change convention. He received a B.S. degree in physics and an M.S. degree in meteorol ogy from the University of Toronto.
References (1) (2)
(3)
(4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)
(15)
Phillips, D. "The Climates of Cana da"; Supply and Services Canada: Ot tawa, ON, 1990; EN 56-1/1990Έ. "The Canadian Climate Program: Ca nadian Climate Program Board"; En vironment Canada: Downsview, ON, 1993. " O c e a n s , Carbon and Climate Change: An Introduction to Joint Glo bal Ocean Flux Study (JGOFS)"; Sci entific Committee on Oceanic Re s e a r c h ; I n t e r n a t i o n a l C o u n c i l of Scientific U n i o n s : Kiel. Germany, 1990. Glooschenko, W. A. et al. /. Geophys. Res. 1994, 99, 1423-28. Bubier, J. L.; Moore. T. R.; Roulet, Ν. Τ. Ecology 1993, 74, 2240-54. Moore, T. R.; Roulet, Ν. Τ. Geophys. Res. Lett. 1993, 20, 587-90. Hall, F. G. et al. IEEE Geoscience and Remote Sensing Society Newsletter 1993. 86, 9-17. Kurz, W. Α.; Apps, M. J. Water Air Soil Pollut. 1993. 70, 163-76. Barker, H. W.; Van Zyl, B. /. Clim. 1993, 6, 858-61. Boer, G. J.; McFarlane, Ν. Α.; Lazare, M. /. Clim. 1992, 5, 1045-77. Mysak, L. Α.; Stocker, T. F.; Huang, F. Clim. Dynam. 1993, 8, 103-16. Verseghy, D. L.; McFarlane, Ν. Α.; Lazare, M. Int. ]. Climatol. 1993, 13, 347-70. "Modelling the Global Climate Sys tem"; Environment Canada: Downs view, ON, 1994; CCD 94-01. "Climate Change and Canadian Im pacts: The Scientific Perspective"; Canadian Climate Program Board, En vironment Canada: Downsview, ON, 1991; CCD 91-01. "Climate Change and Canadian Im pacts: 1993 Update on Scientific Per spectives"; Canadian Climate Pro gram Board, Environment Canada:
Downsview, ON, 1994. (16) Climate Change Digest; Reports #CCD 87-2 through CCD 94-2; Environment Canada: Downsview, ON, 1987-1994. (17) Wall, G.; Sanderson, M., Eds.; Pro ceedings, Symposium on Climate Change: Implications for Water and Ecological Resources; University of Waterloo: Waterloo, ON, 1990; Occa sional Paper No. 11. (18) Wall. G., Ed.; Proceedings, Sympo sium on the Impacts of Climate Change and Variability on the Great Plains; Calgary, Alberta: University of Waterloo: Waterloo, ON, 1990; Occa sional Paper No. 12. (19) "Adaptation to Climate Change and Variability in Canadian Water Re sources"; Environment Canada: Downsview, ON, 1993; CCD 93-02. (20) Cohen, S. J. Clim. Change 1991, 19, 291-317. (21) Williams, G.D.V. et al. In The Impacts of Climatic Variations on Agriculture, Vol. 1; Perry, M. et al., Eds.; Reidel: Dordrecht, The Netherlands, 1987. (22) Smit, B.; Brklacich, M. Canadian Ge ographer 1992, 36, 75-8. (23) Arthur, L. M. Prairie Forum 1992, 17, 97-109. (24) Wall, G., Ed. Proceedings, Sympo sium on Implications of Climate Change for Pacific Northwest Forest Managment; Seattle, Washington; University of Waterloo: Waterloo, ON, 1990; Occasional Paper No. 15. (25) Rizzo, B.; Wiken, E. Clim. Change 1992, 21, 37-55. (26) "Implications of Climate Change for Down Hill Skiing in Quebec"; Envi ronment Canada: Downsview, ON, 1988; CCD 88-03. (27) "Implications of Climate Change for Tourism and Recreation in Ontario"; Environment Canada, Downsview. ON, 1988; CCD 88-05. (28) "Impacts of Global Climate Warming for Canadian East Coast Sea-Ice and Iceberg Regimes Over the Next 50— 100 Years"; Environment Canada: Downsview, ON, 1993; CCD 93-03. (29) Wall, G., Ed.; Proceedings, Sympo sium on Impacts of Climate Change on Resource Management in the North; Whitehorse, NWT; University of Waterloo: Waterloo, ON, 1992; Oc casional Paper No. 16. (30) Woo, M. K.; Lewkowicz, A. G.; Rouse, W. R. Phys. Geogr. 1992, 13, 287-317. (31) Lonergan, S.; DiFrancesco, R.; Woo, M. K. Clim. Change 1993, 24, 331-51. (32) "Socio-Economic Assessment of the Physical and Ecological Impacts of Climate Change on the Marine Envi ronment of the Atlantic Region of Canada—Phase 1"; Environment Can ada: Downsview, ON, 1988; CCD 8807. (33) "Implications of Climate Change for Small Coastal Communities in Atlan tic Canada"; Environment Canada: Downsview, ON, 1990; CCD 90-01. (34) " M B I S : M a c k e n z i e Basin Impact Study, Interim Report # 1 " ; Environ ment Canada: Downsview, ON, 1993. (35) Mortsch, L. et al., Eds.; Proceedings of the Great Lakes St. Lawrence Basin Project Workshop; Quebec City, P.Q.; Environment Canada: Downsview, ON, 1993.
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