Download Impacts of Climate Change on Ontario and the Canadian Arctic

Impacts of Climate Change on Ontario and the Canadian
Arctic
(10.2 pgs. 412-413; 10.3 pgs 419-421)
Climate change is one of the most serious environmental threats
facing the world today. The science is clear: as global temperatures
increase, we can expect more severe-weather events, widespread
water shortages, human health problems, and other major impacts.
http://davidsuzuki.org/issues/climate-change/
Activity:
In groups of 4, you will read about an area of impact (e.g. Water
impacts in Ontario) by climate change. You will write down on the
large sheet of chart paper provided to you what you think are the
main points about that area. You will then decide which are the 3 or
4 most important effects and post your sheet for classmates to read.
You will then complete the following table, writing down notes from
the other areas of impact summarized by the other groups.
Canadian Arctic: How changes in the Arctic affect the rest of the world
Area of Impact
Albedo Effect
Release of GHG
Ocean Currents
Sea Level Rise
Biodiversity
Most Important Effects (top 3 or 4 points)
Ontario
Area of Impact
Temperature and
Precipitation
Most Important Effects (top 3 or 4 points)
- Warmer winters – heating costs may go down
- More extremely hot das in the summer – more heat
waves.
- Shift in precipitation patterns – some areas drier and
others wetter.
- More frequent rainstorms.
Water impacts
Ecosystems
Disease and Illness
Agriculture and Forests
Electricity Use
- Less electricity needed in winter.
- More electricity needed for air conditioning in the
summer – more blackouts.
- Less hydro power available if lake levels drop,
increasing our need for fossil fuels.
Health Impacts
Climate change will have a strong impact on human health. As climate change brings
tropical weather to higher latitudes, tropical diseases like the West Nile virus will follow.
Ecosystem disruption will make the outbreak of water-borne diseases more likely.
Air pollution, which in Canada is largely caused by fossil-fuel use, is already a scourge
on public health. Climate change will make smog more intense, and will lead to even
higher rates of asthma and heart disease. The most devastating casualties will be
inhabitants of poor countries, where there is little infrastructure to deal with changing
water tables and increased extreme weather. Among the world's least privileged, the
potential for climate-induced disaster is enormous.
Deadly heat
Climate change will cause high-latitude regions, like Canada, to warm drastically. With
tropical heat comes tropical illnesses, and large increases in heat-related deaths.
Heat can aggravate health problems, particularly for the old, the young and the ill. For
example, Montreal currently has approximately 70 annual heat-related deaths, while
Toronto has 20. According to the World Health Organization, these figures are expected
to climb to 460 and 290 respectively by 2020 due to climate change.
A hotter world is a sicker world
Rising average temperatures will likely extend the ranges of disease-carrying organisms
like mosquitoes, rodents and bats. In 1998, drought followed by heavy rains in western
North America led to a sharp increase in the population of deer mice, which carry
hantavirus.
The West Nile virus has entered the United States and is moving northward as the
continent warms.
Disease-causing tropical plants have also begun migrating northward. A tropical fungus
invaded Vancouver Island in 2002, killing one and injuring 52.
Global warming may also increase the risk of respiratory diseases because grasses and
allergenic pollens grow more profusely in a warmer environment. A 2002 study showed
that ragweed—a potent allergen producer—grew up to 61 per cent faster under
conditions expected by 2050.
Water impacts
Climate change will seriously affect water resources around the world. Changing water
levels, temperatures and flow will in turn affect food supply, health, industry,
transportation and ecosystem integrity.
Ontario's quarter-million lakes and countless rivers and streams hold about one-third of
the world's freshwater. The province's 11-million people rely on these waters, as well as
on groundwater and rainfall, for drinking, agriculture and industrial uses. Forty-five
percent of Quebec residents take their water from the St. Lawrence River, which flows
from the Great Lakes. Projected changes in rainfall, evaporation and groundwaterrecharge rates will affect all freshwater users.



Lake levels are expected to decline in both inland lakes and Ontario's four Great
Lakes, as more moisture evaporates due to warmer temperatures and less ice
cover.
Reduced summer water levels are likely to diminish the recharge of groundwater,
cause small streams to dry up, and reduce the area of wetlands, resulting in
poorer water quality and less wildlife habitat.
Climate change will also mean an increase in the frequency and severity of
droughts and flooding.
Glaciers
• Fact: Scientists estimate that globally glaciers are losing 92 cubic kilometres of ice per
year. That's as much water used by Canada's homes, farms and factories over six
years.
Glaciers store snow like bank accounts store money; they hold snow in the winter and
release water when it's most needed, during hot, dry summers and periods of drought.
However, global warming is cashing in on a bank account that has been built over
thousands of years but isn't being replenished.
Annual water flows from glaciers are diminishing, as less ice remains every year. Late
summer flows of the Mistaya River in Banff National Park have decreased 39 per cent
over the last 50 years alone. Experts say that communities as far as 3,000 kilometres
from the mountains—such as those on Hudson Bay—will be affected in the decades to
come if warming continues.
Ecosystem Impacts
Climate change is altering the pattern of life on the planet, causing widespread species
extinction, migration and behaviour changes.
A changing climate forces plants and animals to migrate in order to survive. However,
research has shown that most plant species are able to migrate at only 1/10th of the
speed required to keep up with human-induced climate change.
To make matters worse, human settlements and infrastructure have already subdivided
ecosystem habitat into isolated patches. Climate change will make many of these
patches uninhabitable for the species that live there. Northern countries like Canada are
experiencing some of the most serious impacts on biodiversity:
Canada's increasingly dry Northern boreal forests, stretching across the Canadian Shield,
have seen burns escalate from one-million hectares to three-million in the last decade.
Female caribou migrate in spring to small pockets of vegetation where they feed and raise
their calves. But for the past decade, spring has come so early that by the time the caribou
reach the coastal plain, their principal food plant has already gone to seed.
A receding Arctic icecap and earlier-than-normal breakup of sea ice has affected polar
bears, which depend on sea ice to hunt seals. Recent studies shows polar bears in some
regions are down a third in body weight. The latest generation of seals have also been
found to be much thinner than usual.
One study looked at whether species can migrate quickly enough to survive in a rapidly
changing climate. It found that Canada is likely to be one of the hardest hit (PDF) because
of its northern location, and that more than 45 per cent of Canada's habitat could be lost by
the end of this century, resulting in a 20 per cent loss of species in vulnerable ecosystems,
such as the Arctic and boreal forests.
Forest Impacts
Climate change is threatening the health of forests around the world. As temperatures
rise, weather patterns and the availability of water also change, altering the ability of
trees to survive.
Canada's forests cover almost half of the country's landmass and make up 10 per cent
of the world's forest cover. Forests are a crucial part of Canada's natural heritage,
wilderness areas and economy.
Although more carbon dioxide in the atmosphere may encourage tree growth, the
negative impacts of climate change are expected to far outweigh any benefits.
Forest dispersion and shifting
Although scientists predict an increase in precipitation due to climate change, it will likely
not be sufficient to keep up with increased evaporation from rising summer
temperatures. This will lead to decreased soil moisture, which will cause more droughtresistant trees or grasslands to displace existing forest ecosystems.
Forest fires
As hotter, drier summers increase evaporation they will also increase the risk of forest
fires across most of Canada, and increase the severity of those fires. According to the
government of Canada, both fire frequency in Canada's boreal forest and total area
burned have increased over the last 20 to 40 years.
Rising tree lines
The alpine tree line is one of the most distinctive habitat transitions, separating
continuous subalpine forest from the alpine environment.
Tree line elevation is determined by growing-season temperature. As global
temperatures rise, tree lines are expected to advance upslope and northward, shrinking
the alpine environment (e.g., invading alpine meadows) and fragmenting wildlife habitat.
Climatologists believe that a rise in global temperatures of 3.25 degrees Celsius would
be equivalent to an ecological shift upwards of about 500 metres in altitude. Alpine
species confined to the tops of low-lying mountains risk extinction as the habitat is taken
over by forests.
How will Arctic warming affect the rest of the planet?
Arctic warming and its consequences have worldwide implications.
Albedo effect
The amount of the sun’s energy reflected back to space decreases as snow and ice melt,
leading to a more intense surface warming.
As snow and ice are bright white, most of the solar energy that reaches them is reflected
back to space. This is one reason why the Arctic remains so cold. As air temperatures are
increasing, snow and ice now tend to form later in the autumn and melt earlier in the
spring. The darker land and water surfaces, which absorb more of the sun's energy, are
thus longer uncovered. This warms the surface further, which, in turn, causes faster
melting, creating a ‘positive feedback loop’ that amplifies and accelerates the warming
trend. This is one reason why climate change is particularly rapid in the Arctic.
Ocean currents
The melting of Arctic ice and increased regional precipitation can add freshwater to the
oceans, and potentially affect ocean currents in the North Atlantic.
One of the ways the sun's energy is transported from the equator toward the poles is
through the globally interconnected movement of ocean waters primarily driven by
differences in heat and salt content, known as the thermohaline circulation (“thermo” for
heat and “haline” for salt).
At present, the Gulf Stream current that flows from the Gulf of Mexico to the coasts of
Europe warms the winds and provides much of the moisture that falls as precipitation
over northwestern Europe. As the water moves northward, it becomes cooler, saltier and
denser. As a result, surface water eventually becomes heavier than the water(s) below it
and sinks deep into the ocean. This process drives the global seawater “thermohaline
circulation” (sometimes referred to as the “conveyor belt”) which pulls warm waters
northward. Part of this global circulation is known as the Gulf Stream, providing some of
the heat that keeps Europe warmer in winter than regions of North America at the same
latitude. Climate change could interfere with the formation of the cold, dense water that
drives oceanic circulation and thus bring about further changes in climate.
Slowing the thermohaline circulation would have several major global effects:



The decreasing transport of CO2, contained in water from the surface to the deep
ocean. This would contribute to further increases in the level of CO2 in the
atmosphere and thus to further warming (due to CO2).
Regional cooling, for instance in Europe. This could result from the slowing of
the northward transport of heat by Atlantic Ocean currents, even while the rest of
the planet warms rapidly.
Reduced sinking of cold, dense water in the Arctic. This would, in turn, reduce
the amount of nutrients carried back toward the surface elsewhere in the world
that sustain marine life living near the surface
Release of GHG
As warming progresses, more greenhouse gases could be released into the atmosphere
by the thawing of the permafrost. However, warming can increase biological growth, and
thus absorption of CO2.
Carbon is currently trapped as organic matter in the permafrost (frozen soil) of the Arctic.
During the summer, when the top layer of permafrost thaws, and plant material on dry
land or ponds decomposes, methane – a very potent greenhouse gas – and CO2 are
released. Higher temperatures lead to an increase in the rate of decomposition and gas
production, and possibly to a feedback loop with more warming that results in more
releases, causing more warming, and so on.
In the Arctic, vast amounts of methane are trapped in permafrost and in cold ocean
sediments in a solid icy form (as methane hydrates or clathrates). A rise in temperature
within the soil could initiate the release of methane from permafrost to the atmosphere.
Sea Level Rise
By 2100, melting of Arctic glaciers alone will have contributed to a sea level rise of
roughly 5 cm out of the projected 10-90cm total rise for this century. *2 Melting of the
Greenland ice sheet may increase this number significantly.
Projections from global climate models suggest that the contribution of Arctic glaciers to
global sea-level rise will accelerate over the next 100 years. By 2100, the melt of these
glaciers will have contributed to a rise of roughly four to six centimeters or even more
according to recent estimates. In the longer term, the Arctic contribution to global sealevel rise is projected to be much greater. Some climate models project that local
warming over the Greenland Ice Sheet will eventually lead to its complete disappearance,
with a resulting sea-level rise of about seven meters.
Biodiversity
Access to Arctic resources is likely to be affected by climate change, including: wildlife,
such as whales, seals, birds, and fish sold on world markets; and oil, gas and mineral
reserves.
Arctic ecosystem changes will have an impact on a global scale, notably by affecting
migratory species’ summer breeding and feeding grounds.
Arctic wildlife resources such as seals, reindeer, birds and fish have long been sold on
world markets. Arctic seas contain some of the world's oldest and most productive
commercial fishing grounds, which provide significant catches for many Arctic countries,
as well as for the rest of the world.
Climate-related changes in Arctic ecosystems will have consequences not only at local
level but also on a global scale because of the many links between the Arctic and the rest
of the planet. Many species from around the world migrate to the Arctic in summer and
depend on it for breeding and feeding. Climate change will alter some of their habitats
significantly.
Expansion of the forests towards the North, for instance, may reduce the size of tundra
areas, which are important breeding grounds for hundreds of millions of migratory birds.
Indeed, a number of bird species are projected to lose more than 50% of their breeding
area during this century, including several globally endangered seabird species.
Climate-related changes in arctic ecosystems will not just have consequences for local
people and other living things that depend on these systems for food, habitat, and other
goods and services, but will have impacts at the global level because of the many
linkages between the Arctic and regions further south. Many species from around the
world depend on summer breeding and feeding grounds in the Arctic, and climate change
will alter some of these habitats significantly.