Canadian Climate Impacts and Adaptation Research Network – Ontario
Briefing Prepared for the Senate Standing Committee on Forestry and Agriculture
Dr.David Pearson. Chair, C-CIARN-Ontario; Professor, Department of Earth Sciences, Laurentian University, Sudbury, ON. P3E 2C6 (email@example.com)
Dr.Gerard Courtin, Professor Emeritus, Department of Biology, Laurentian University, Sudbury, ON. P3E 2C6 (firstname.lastname@example.org)
C-CIARN-Ontario is housed in
Laurentian University in Sudbury. Over a thousand researchers and stakeholders
are active participants in the Ontario Network. The text of this presentation
has not been distributed to the participants at the time of its submission,
but will have been distributed for comment by the time of the presentation to
Global air temperatures have changed at an unprecedented rate over the past thirty years (Hengeveld 2002, Sharp, 2002). Although there are scientists who argue that the cause is natural, we believe that impact assessments and adaptation strategies should be based on the International Panel on Climate Change reports and on the Canadian climate change model. According to that model by 2050 temperatures in Ontario will have risen by 2 to 3ºC in southern Ontario and by as much as 4ºC in the north near Hudson Bay (Hengeveld, 2000). At the Experimental Lakes Area in northwestern Ontario, from 1970 to1990, air temperatures rose 1.6ºC and average annual evaporation increased by about 50% (Schindler et al.,1996). Only very substantial reductions in greenhouse gas emissions going far beyond the Kyoto Protocol might ameliorate this rise. Furthermore, there is good reason to believe that air temperatures will not stabilize until decades after emission reductions are implemented. Reductions in emissions will not turn the clock back, their purpose is to protect distant generations and the long term biodiversity of the planet. They represent an ethical issue. On the other hand, adaptation involves strategies to protect the well being of our own generation and is sometimes seen as only a matter of protecting human interests. However, adaptation must also involve pro-active steps to protect the biodiversity of existing ecosystems, not just as a resource but as an ethical responsibility.
This brief discusses the Province of Ontario in terms of its ecological zones (ecozones) from north to south; the Hudson Plains, the Boreal Shield and the Mixedwood Plains (Fig. 1) with the emphasis on the latter two.
In terms of area the Boreal Shield occupies the largest portion of Ontario. It is of high economic importance but with a relatively small population. The ecozone rests on the glacially-scoured Precambrian Shield. The dominant vegetation is coniferous with black and white spruce, balsamfir, and jack pine. Aspen poplar and white birch are also important at the southern fringes of the ecozone. The economic base is mainly lumber, and pulp and paper. Scouring of the Shield rocks has resulted in minimal soil and a rolling topography with tens of thousands of lakes that foster a very important recreation and tourism industry.
Figure 1. Ecozones of Ontario. Source: Smith et al., 1998
The impact of climate change will not be one simply of temperature. The Boreal Ecozone is the most important natural ecosystem in Canada both economically and in aerial extent. The boreal forest boundaries are dictated by the mean summer position to the north, and the winter position to the south, of the front of the Arctic air mass. The Arctic front, in turn, is governed by atmospheric circulation, duration of snow cover, and freezing and thawing of water bodies across the entire northern hemisphere. Warming will have an impact on the entire atmospheric circulation in ways that are very difficult to predict. Hence, a range of possibilities exists with respect to both northward shift and latitudinal extent of the Boreal forest with climate change. It is reasonable, however, to suggest that there will be a northward shift of the Boreal forest.
Environmental factors. Progressive increase in temperature will not act in isolation. Warming will lead to an increase in evaporation from plants, soil and water bodies. At the same time, current climate models indicate a decrease in precipitation in Ontario not only contributing to further soil drying but to a decrease of runoff into lakes and rivers. The extreme weather events of the past few years have been linked to warming and the prediction is an increase in frequency of such events. The 1998 ice storm in eastern Ontario and Quebec affected more people than any other weather event in Canadian history. The reasons were power transmission lines that were under-designed and no back-up infrastructure in the case of widespread power outages.
The effect of
warmer temperatures will lead to an increase in the incidence of ice storms in
regions where presently winter precipitation falls principally as snow.
Flora and fauna. In the Boreal Forest, the question will be whether the overall environmental conditions that a rise in temperature will bring will be too severe for the flora and fauna (avian, terrestrial, aquatic) to adapt. This will be especially true in regard to the flora where movement is the result of progressive re-establishment from seed. Because seeds of different species vary in size and they way in which they are transported it is very unlikely that the forests of the Boreal Shield will move as a whole; rather, one must expect that the composition will change as certain species out-compete others.
Shifts in fauna already are being seen. For example, opossums are now being found as far north as Barrie, which is well beyond their historical northern limit on the northern shore of Lake Erie. Turkey vultures are now commonplace in areas where they were rarely seen ten years ago (Mallory, pers. comm.).
animals such as the woodland caribou whose present range extends onto the tundra
are likely to cope with shifts in their habitat.
The increased precipitation, however, falling either as rain or freezing
rain, will form an ice crust on the snow surface that will affect movement of
ungulates such as moose, elk and woodland caribou thus making foraging more
difficult and increasing vulnerability to predation by wolves and coyotes (Hamr,
Fire, Insects and Disease. Fires will be more intense and more frequent because of drought. In the clay belt of northeastern Ontario forests have a very long fire cycle because of abundant soil moisture. More frequent burning will prevent forests reaching maturity and this will have an impact on foraging of ungulates and the range of animals such as pine marten that favour old-age forest stands (Mallory, pers. comm.). Drought will also cause trees to become stressed and hence more vulnerable to disease. Warmer winters will allow the northward spread of disease organisms that until now have been kept in check through winter mortality.
Communities. Communities in the Boreal ecozone are generally small and widely separated. At the same time their existence is tightly coupled to a healthy Boreal forest in its entirety; forests, lakes, rivers and the entire fauna. They play an important role in the economy of the region because they provide the human resources for the forestry and mining sectors, and are the foci for hunting and fishing. Typically, these communities are serviced by a single transportation, communication, and power corridor that leaves them very vulnerable to extreme weather. The development of local hydro generation and wind farms, where appropriate, would provide a large measure of independence and safeguard the population.
First Nations. First Nation people are distributed across the province in reserves that are disjunct. By virtue of the treaties signed with the Government of Canada the reserve boundaries are geographically set and will not change even if the characteristics of the environment, flora and fauna change. Native traditions that have developed under conditions of a more or less stable environment could face upheaval and natives could face hardships for which they are ill-adapted. This problem is exacerbated by the fact that, for the most part, reserves are limited in size so that latitudinal movement in an attempt to keep pace with environmental changes is unlikely to be an option. One important activity in terms of livelihood is trapping. In the event of warming animal ranges will move northward and hence will be lost from the reserve. Their replacement with animals with a more southerly range to which trappers might accommodate with time is not likely because natural habitats have been severely reduced in size or eradicated completely by the increase in urbanization in their source areas.
Ultimately the human population of Ontario will continue to rely on forest- and farm-based ecosystems. Research into pro-active adaptation strategies is of paramount importance.
Plants do not grow in isolation but rather they reflect the sum total of their environment. As the environment changes there will be a natural reaction of the forest to a catastrophic disturbance because of the rapid change in the climatic regime. If warming occurs as rapidly as predicted then natural rates of spread will not be able to keep pace. It will be necessary to regenerate artificially with genetically adapted strains and species suited to the changed conditions.
One possible advantage of a warmer climate and a longer growing season, where moisture is adequate, may be faster growth and greater yields for agricultural crops and shorter rotation times in the case of forest trees.
The Mixedwood Plains
The Mixedwood Plain Ecozone is situated south of the Boreal shield. The bedrock is mostly flat-bedded limestones overlain by glacial deposits. The deep overburden, with a high content of limestone and clays, is responsible for highly productive soils. As a result the mixed wood plains are characterized by intensive agriculture, greater density of transportation facilities and a concentration of manufacturing and urbanization (Smith et al., 1998). The original forest is defined as the Northern Hardwoods-White Pine-Hemlock segregate of the Eastern Deciduous Forest. Only in a narrow band along the northern shore of Lake Erie is this replaced by the Beech-Maple segregate. Both segregates now exist only in a highly fragmented form as a result of extensive agriculture, settlement and industrialization.
Fortunately, 725 km of the Niagara Escarpment is subject to environmental land use planning that was approved to protect and buffer the ecosystems of the escarpment. It is a United Nations Biosphere Reserve and may prove to be a corridor and lifeline for species moving under the influence of climate change.
Climate. The climate of the Mixedwood
Plains is much milder than that of the Boreal Shield both because of lower
latitude and because of its proximity to Lakes Huron, Erie and Ontario.
The lakes have a marked moderating effect because the lakes freeze later
in the autumn, and remain frozen for longer in the spring, than the land.
Climatic warming will have the effect of reducing the length of ice cover
with potential effects on crop species that are frost susceptible.
Flora and Fauna.
Agriculture dominates the flora and
fauna of the region. Farming is
primarily cattle, grain and oilseed, and locally, vegetables.
Fruit orchards and vineyards dominate the Niagara Peninsular and lands
bordering on Lakes Ontario and Erie where delayed growth in the spring, because
of the adjacent cold lakes, prevents damage to buds and flowers.
In the autumn the warm lake water extends the growing season so that
fruits have time to ripen.
Production of ice wine, for which Ontario is world famous, may be either reduced or halted if there is insufficient frost to reduce the water content of the grapes.
Although warming should have the effect of increasing the northward extension of Beech-Maple forest this is unlikely to occur because the extreme fragmentation of existing forested areas will make it almost impossible for seeds to bridge the gaps that exist. Furthermore, birds that could act as a vector for dissemination have been reduced drastically in number or extirpated because the forest patch size is too small to maintain a breeding population (Bolen and Robinson, 1995).
A milder winter infers more frequent periods of thawing which disrupts the natural hardening process that allows trees to survive the freezing of live tissues. With frequent thaws that ability is lost and subsequently the trees suffer frost damage. At the same time an increased incidence of ice storms and loss of power could devastate farm operations that are dependent on electricity.
Increased evaporation and possible reduction in precipitation means that drought stress is likely to be widespread. Lowered water tables and aquifers that are not recharged will diminish the potential for irrigation.
The impact of climate
change on environmental factors will be similar to that suggested for the Boreal
ecozone but may not be as severe.
Insects and Disease.
Although the disease organisms will be different from those in the Boreal
ecozone, the impact that climate change will bring about will be very similar.
Less snow cover will mean less protection for insects that over-winter
under the snow but milder winters will mean greater survival for others.
Communities. The rural communities of southern Ontario are closely tied to the health of their natural environment through agriculture and tourism. Many are on the fringe of large urban settlements and are subject to intense development pressure. It can be argued that only the Niagara Escarpment Plan protected the Niagara Peninsula from urban development and kept the agricultural land available for the vineyards of today's wine industry. It is doubly important in vulnerable rural communities that the viability of agriculture be sustained by pro-active adaptation to climate change rather than by reactive adjustments to unforeseen impacts.
Crop varieties will have to be selected that are climatically suited and practices employed that diminish the risk of disease. With milder climate the possibility of insect infestations may increase. There is a need to avoid monocultures in order to minimize the use of pesticides.
In terms of water there is a need for water source protection and water use conservation. North Americans are notoriously wasteful of water in comparison to Europeans. The Great Lakes must not be seen as an easy or obvious solution when their water levels will be at risk.
The Hudson Plains
The Hudson Plains ecozone presently lies in the zone of discontinuous permafrost and is characterized by black spruce and muskeg to the south and largely treeless arctic tundra to the north. The effect of warming on this ecozone is likely to cause an extension of spruce and muskeg to the Hudson Bay coast. It is likely that any change in the substrate, due to thawing, will be minor and have little or no effect on buildings in the scattered communities along the coast. The effect of warming the land may have a two-fold effect. First, the peat and lignite that compose the muskeg are presently a carbon sink because of the cold and an elevated water table. Warming will probably increase substrate temperature and evaporation. This will lead to an increase in the rate of decomposition and release of both carbon dioxide and methane (Gates 1993). Second, warming of the land will have an effect on the temperature of the rivers that drain it and that are where Salmonids (arctic char, brook trout and arctic grayling) spawn. A series of very warm summers in the early 1990s led to highly elevated water temperature in the Sutton River that caused documented fish kills (Gunn, J. pers. comm., 2002). Such findings suggest that the warming presently being seen will have a very serious impact on rivers that are part of the northern economic base because of the excellent fishing.
also have a very low tolerance to changes in water temperature during spawning
and any increase could have a dramatic effect on reproductive success and hence
- The human communities and the ecosystems
that they inhabit cannot be looked at in isolation.
As any given ecosystem changes in character, as a result of the
combined impacts of climate change, so the character and the economic base
of individual communities will have to change.
- Warming will lead to the northward extension of agriculture and a requirement for research into the appropriate crops and agricultural practices to meet the challenge. Experimental agricultural stations such as New Liskeard need to be supported as soon as possible to help in pro-active adaptation by agricultural communities.
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