Climate Change and Biodiversity Turmoil

Climate change will have enormous impacts on Ontario’s natural environment. Increased air and water temperatures, along with changes to rain and snow patterns, will reshape the ecology of the province. Some native plants and animals will be able to move with or adapt to these changing conditions, others will not. The ranges of other species – not previously found in Ontario – will expand into our province. These changes to Ontario’s ecology will have profound repercussions on our communities and economy.

Climate change adds to the other pressures that already imperil Ontario’s biodiversity. Habitat loss and fragmentation, harvesting and overexploitation, pollution, and invasive alien species threaten many of our province’s native species and ecosystems. These stressors can have a cumulative effect that accelerates pressures on the province’s plants and animals. Across the planet, it is estimated that 20 to 30 per cent of species will be at increased risk of extinction if increases in global average warming exceed 1.5 to 2.5°C.

Increases of average winter temperatures up to 7ºC for parts of northern Ontario by the year 2050, as well as increases in winter precipitation up to 39 per cent with more of it falling as rain, are projected.

In southern Ontario, projections forecast average summer temperature increases of 2.6ºC, but with no real corresponding change in precipitation. These projections are based on “middle of the road” assumptions using moderate greenhouse gas (GHG) emission scenarios. Additionally, it is predicted that there will be a higher number of and more intense extreme weather events, such as droughts, heat waves, severe rainstorms, tornadoes and windstorms each year across Ontario.

Ontario is divided into 14 ecoregions – areas that are distinguished by their geology and climate (i.e., temperature, precipitation, humidity). These ecoregions are used to understand and manage the different parts of our province, through wildlife management programs or the management of protected areas. Ontario will undergo enormous ecological changes in the 21st century as these boundaries will shift dramatically because of climate change.

The climatic conditions of most of southern Ontario (ecoregion 6E) will move more than 500 km north, and will be restricted to the area around Marathon by the last few decades of the 21st century. However, just because southern Ontario’s climate shifts northwards does not mean that all its plants and animals will be capable of moving along with it. Many species will not be able to migrate quickly enough to follow changing climate patterns. Additionally, natural barriers (like the Great Lakes) and human barriers (like highways and cities) will impede or prevent many species from following our province’s changing climate. Moreover, the movement of species also may be restricted by different geologic and soil conditions. As a result, there will be dramatic changes in which species live where in Ontario.

Ontario’s Ecology Will Be Radically Reshaped by Climate Change

Species that inhabit the northern part of Ontario will be among the most visibly affected by climate change. In effect, some of these species will “be pushed off the planet” as there is nowhere left for them to go. As a result, some species may soon become extirpated from Ontario. For example, our province is home to the southernmost population of polar bears (Ursus maritimus) in the world – a species that is widely recognized as suffering the most immediate impacts of climate change. There is a high probability that Ontario’s population of 900-1000 polar bears will be gone from the province within 45 years due to decreases in sea ice in Hudson Bay, which constitute an integral part of their habitat.

Many of our province’s other sub-arctic and arctic species will be imperilled because of rises in temperature, changes in snow conditions, and decreases in sea ice. Ontario’s beluga whales (Delphinapterus leucas), arctic foxes (Alopex lagopus), and ringed seals (Pusa hispida) have all been identified as facing serious risks from climate change.

Climate change will also have an impact on more southerly species, like Ontario’s black bear (Ursus americanus) populations. Such species may not disappear because of climate change, but their range, behaviour and interactions with other species will likely change. The limits of black bear distribution will likely move northward due to warmer climates. Because species with restricted habitat ranges will have the most problems dealing with climate change, black bear populations with fragmented habitats may be most affected. Another concern is that warmer temperatures could cause the early emergence of bears from hibernation – potentially causing a “mismatch” in the availability of food for bears. As well, climate change will alter precipitation patterns, decreasing food availability for black bears due to berry crop failures.

Species that were historically not adapted to Ontario’s climate already are shifting northwards into the province from the United States. For example, warmer temperatures create a more hospitable environment for black-legged ticks (Ixodes scapularis), also known as deer ticks. They carry bacteria which causes Lyme disease in humans – an infectious disease that once was almost non-existent in Ontario. The range of these ticks will expand to encompass all of southern Ontario by the 2020s, possibly reaching James Bay by the 2080s.

The Virginia opossum (Didelphis virginiana), native to the southern United States, can already be found in Ontario due to milder winter temperatures in recent years. Additionally, some migratory species will expand their range in Ontario, like the eastern bluebird (Sialia sialis) which is predicted to begin over-wintering in southern Ontario rather than flying south. However, the populations of other migratory birds are expected to decline because of climate change due to the mismatch of their food requirements and food availability. Other species will be displaced; the familiar black-capped chickadee (Poecile atricapillus) will have much of its range taken over by the Carolina chickadee (Poecile carolinensis) due to warmer temperatures.

Warmer temperatures will also contribute to the range expansion of white-tailed deer (Odocoileus virginianus), already perceived to be hyper-abundant in southern Ontario because of land-clearing and the lack of natural predators. However, higher temperatures also are expected to lead to higher mortality of moose (Alces alces) in northern Ontario from hypothermia, as freezing rain events are projected to increase by 85 per cent in this part of the province. Other effects on moose likely will include increased heat stress causing range contraction, greater nutritional stress causing lower calf production, and higher occurrences of winter tick infestations leading to mortality. Climate change also will affect woodland caribou (Rangifer tarandus caribou) in numerous ways, including greater disturbances to their habitat based on increased forest fires and higher fire intensities.

These swings in the population and range of one species can have a ripple effect on others. For example, predator and prey species are so closely interdependent that each side of this dynamic can drive changes in the population and range of the other. As result, these shifts in cervid populations (of white-tailed deer, moose, woodland caribou and American elk) caused by climate change will have effects on species such as grey wolves (Canis lupus) and eastern wolves (Canis lycaon). For example, increased snowfall in northern Ontario could lead to higher predation rates on cervids.

Put another way, climate change will have a domino effect on the province’s ecological systems. In general, climate change will affect the number and intensity of pests, invasive alien species, and diseases. For example, species like gypsy moths (Lymantria dispar) and mountain pine beetles (Dendroctonus ponderosae) were historically restricted in range by colder winter temperatures. Shifts in forest composition to warmer and drier conditions will likely favour jack pine in some parts of Ontario, but it in turn could be heavily affected by mountain pine beetles. Coupled with increased blow-downs, more droughts, and changes to fire cycles, extraordinary pressures will be placed on the natural resilience of forested ecosystems. A striking change will occur as Ontario’s northern boreal forest shrinks in size, being overtaken by grasslands in the northwest.

Ontario’s water resources will also be affected by climate change. For example, warmer water and air temperatures, increased evaporation from water bodies and adjacent lands, longer ice-free periods, and the spread of invasive alien species will alter the ecology of the Great Lakes basin. In addition to historical fluctuations, it is projected that the water levels of the lower four Great Lakes could drop by as much as 115 cm within the next four decades. Additionally, coastal wetlands will be affected by lower lake levels, triggering changes in which species are present.

Warming water temperatures have already begun to change the range and abundance of fish species. In the next century, it is projected that lake water temperatures will rise 4.5°C. Moreover, the ecology of dimictic lakes (i.e., lakes that mix twice a year, in the spring and the fall) will be changed by rising temperatures, with forecasts showing that the province’s lake trout (Salvelinus namaycush) habitat will be reduced by almost a third by the year 2100.

Changes to precipitation patterns and rising air temperatures will affect wetlands which serve as important habitat for waterfowl, amphibians, and many other species. For example, warming temperatures act as a catalyst for epidemics that are a leading cause in the decline of frog populations around the planet. Climate change will likely cause smaller wetlands to dry up, while larger ones will experience greater variations in water levels and become seasonal.

Northern peatland ecosystems, which are essentially composed of vegetation that has decayed over centuries to form waterlogged soils, will also likely be significantly altered by climate change. As the Expert Panel on Climate Change Adaptation warned, “Losing that carbon to the atmosphere as GHGs is a risk of global proportions” as temperatures rise and peatland ecosystems are lost.

ECO Comment

Humans are manufacturing environmental change on a planetary scale. Our actions are causing severe repercussions on our global climate and the Earth’s biological diversity. The enormity of these changes has led some to remark that our own spiralling population growth, sprawling megacities and rampant use of fossil fuels have changed the Earth to such an extent we are entering a new geological era: the Anthropocene. The total effect on the Earth’s plants and animals is described as a mass extinction event.

Many aspects of climate change and biodiversity loss are inseparable. Addressing one in isolation from the other would be a short-sighted mistake. Climate change adaptation and biodiversity conservation must be considered a two-pronged and interrelated approach to how the Ontario government plans and manages our land and water, fish and wildlife, and communities and economy.

The Ontario government started down the right path in 2005 by creating a biodiversity strategy. However, this strategy was laid out as a five-year plan that expired this year. The ECO believes that the time has come to renew the Ontario government’s commitment to conserve biodiversity, critically reflect on what has worked, and systematically plan for what new actions must be taken. Climate change adaptation must be an integral part of a new biodiversity strategy to direct government action.

In November 2009, the Expert Panel on Climate Change Adaptation, appointed by the Ontario government, suggested that a new long-term approach be taken. The expert panel recommended, Ontario’s Biodiversity Strategy (2005) is a good starting point but, like others of its time, it did not fully embody an approach based on ecosystems being rapidly overtaken by more southern climate envelopes. A “Biodiversity Strategy for 2050” should envisage a very dynamic environment in which the province’s system of parks, reserves and other types of protected areas, as well as areas under the Niagara Escarpment Planning and Development Act, the Oak Ridges Moraine Conservation Act (2001), and the Greenbelt Act (2005), become nodes in a system of migration paths or “greenways” of interconnected habitat.

The ECO believes that a reconceived biodiversity strategy should clearly detail the responsibilities of all relevant ministries of the Ontario government, describe decisive actions that will be taken, contain quantifiable targets to track progress, and specify hard timelines for delivery. Without question, it also should specify target program areas, policies, and legislation that need revision to achieve its goals. Conserving biodiversity is all of our responsibility. However, the Ontario government must articulate how it will systematically respond to biodiversity loss in the province, with particular attention to those losses that may be attributed to the impacts of climate change.

Citing This Article:
Environmental Commissioner of Ontario. 2010. "Climate Change and Biodiversity Turmoil." Redefining Conservation, ECO Annual Report, 2009/10. Toronto, ON : Environmental Commissioner of Ontario. 32-36.