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Canada Country Study: A Window on Climate Change in Canada
Over the next century, global temperatures are projected
to undergo a change greater than any seen in the past
10,000 years. Scientists know this will cause unprecedented
disruptions in the earth’s climate which will vary from place to place
and produce a wide range of impacts.
The Canada Country Study is the first-ever national assessment
of the social, biological, and economic impacts of climate change for
Canada. Environment Canada has brought together climate experts
from government, industry, academia, and non-government organizations
to review existing knowledge on climate change impacts and
adaptation; identify gaps in research; and suggest priority areas where
new knowledge is urgently needed.
In Canada, there has been warming of about 1°C over the past century,
with increased annual precipitation over the past 50 years. These
figures are consistent with global trends. Climate change projections
suggest that over the next century, further warming of 1 to 3.5°C will
occur. Based on this scenario, the Canada Country Study found that
the implications of climate change for water resources are a key to
defining overall impacts for all sectors and regions of the country.
Overall, the impacts of climate change on our forests, fish populations,
and agriculture could be extreme. They include:
- longer growing seasons and extension of agriculture further
north, but also risks to agriculture such as moisture deficits,
pests, disease, and fires;
- impacts on fish populations, which could increase in some
areas, mostly in the Arctic and on northern areas of the
Pacific coast, and decrease in others, particularly the lakes
and rivers of the Canadian Shield;
- effects on hydroelectric generating potential, with
increases in Labrador and Northern Quebec, and lower potential in Ontario, the
Prairies, and southeastern B.C.;
- risks to waterfowl populations due to lower water levels in
lakes, rivers, and wetlands; and
- projected changes in the occurrence and severity of
extreme events, which would have serious implications for
the security and integrity of Canada’s natural resources,
social systems, and infrastruc-ture with subsequent impli-cations
for the insurance industry and supporting public sectors.
In looking at the impacts for Canada, the study drew upon
26 component reports covering six regions of Canada and 20
sectoral and related issues of socioeconomic significance.
Highlights of the regional reports are included here. It
is important to bear in mind that uncertainties regarding
the character, magnitude, and rates of future climate change
remain. These uncertainties impose limitations on the ability
of scientists to project impacts of climate change, particularly at
the regional and smaller scales.
British Columbia/Yukon
Climate change will have significant impacts on British Columbia
and Yukon, including increased flood dangers in some areas,
drought in others, and widespread disruption to forests, fisheries, and
wildlife.
Sea levels are expected to rise up to 30 cm on the north coast
of B.C. and up to 50 cm on the north Yukon coast by 2050, mainly
due to warmer ocean temperatures. This could cause increased sedimentation,
coastal flooding, and permanent inundation of some natural ecosystems, and place
low-lying homes, docks, and port facilities at risk.
Other changes that may result from climate change include:
- In winter, increased winter precipitation,
permafrost degradation, and glacier retreat due to
warmer temperatures may lead to landslides in unstable mountainous
regions, and put fish and wildlife habitat, roads, and other
man-made structures at risk. Increased precipitation will put greater
stress on water and sewage systems, while glacier reduction could affect the flow
of rivers and streams that depend on glacier water, with potential
negative impacts on tourism, hydroelectric generation, fish
habitat, and lifestyles.
- Spring flood damage could be more severe both on the coast
and throughout the interior of B.C. and Yukon, and existing
flood protection works may no longer be adequate.
- Summer droughts along the south coast and southern interior
will mean decreased stream flow in those areas, putting fish survival
at risk, and reducing water supplies in the dry summer
season when irrigation and domestic water use is greatest.
Arctic
In the past 100 years, the Mackenzie district has warmed by
1.5°C and the Arctic tundra area by 0.5°, while the Arctic mountains
and fjords of the eastern Arctic have cooled slightly. Future winter
temperature increases of 5-7° over the mainland and much of the
Arctic Islands and modest cooling in the extreme eastern Arctic are
projected. Summer temperatures are expected to increase up to 5°
on the mainland, and 1-2° over marine areas. Annual precipitation
is expected to increase up to 25 per cent.
These changes in temperature and precipitation would have
dramatic effects on tundra and taiga/tundra ecosystems, reducing
them by as much as two thirds of their present size. More than one
half of the discontinuous permafrost area could disappear, with marked
surface instability in the short term.
Wildlife would also be affected,
with many species in fish and streams shifting northward –
150 km for each degree increase in air temperature – and High Arctic
Peary caribou, muskoxen, and polar bears running the risk of extinction.
Climate change would also extend the shipping season in the
Arctic, while rising sea levels in the Beaufort Sea areas would endanger
coastal infrastructure.
Prairies
Current models suggest that climate change could result in
increased air temperatures and decreased soil moisture. There is
less confidence about whether precipitation will increase or decrease
or about how climate change may affect severe weather events. Most
scenarios suggest that the semiarid regions of the prairies can expect
an increase in the frequency and length of droughts.
Some of the potential impacts of these changes include:
- Average potential crop yields could fall by 10-30 per cent, due
to higher temperatures and lower soil moisture. However, higher
temperatures could lengthen the growing season, and may
increase crop production in northern regions where suitable
soils exist.
- Increased demand for water pumping and summer cooling,
due to drought, and decreased winter demand due to higher
temperatures, could push electrical utilities into a summer peak
load position at the same time as hydropower production is
reduced by decreased water flow. This could result in increased
thermal power production with an increase in fossil fuel consumption
and greenhouse gas emissions.
- Semi-permanent and seasonal wetlands could dry up, leading to
reduced production of waterfowl and other wildlife species.
Ontario
Ontario could experience anywhere from 3-8°C average
annual warming by the latter part of the 21st century, leading
to fewer weeks of snow, a longer growing season, less
moisture in the soil, and an increase in the frequency and
severity of droughts.
Other impacts of climate change could include:
- more days when heat stress and air pollution adversely
affect people’s health;
- likely increases in the frequency and severity of forest fires;
- changes to aquatic ecosystems and alterations to wetlands;
As well, water levels in the Great Lakes could decline to
record lows by the latter part of the 21st century, reducing
shipping capacity.
Quebec
If carbon dioxide levels were to double, Quebec would experience average
temperature increases of 1-4°C in the south and 2-6° in the
north. Precipitation would likely remain the same or
decrease slightly in the south, while increasing 10-20 per cent
in the north.
Likely consequences include:
- lower water levels in the St.Lawrence River, which will
affect shipping, navigation, and the marine environment of the river;
- positive effects on agriculture, including a longer growing
season and the extension of agriculture further north.
Atlantic
Climate change in the Atlantic region has not followed the
national warming trend of the past century, and, in fact, a slight cooling
trend has been experienced over the past 50 years. This trend
is consistent with projections by climate models.
Atlantic Canada is particularly vulnerable, however, to rising sea
levels, whose impacts could include greater risk of floods; coastal erosion;
coastal sedimentation; and reductions in sea and river ice.
Other potential impacts include:
- loss of fish habitat;
- changes in ice-free days, which could affect marine transportation
and the offshore oil and gas industry; and
- changes in range, distribution, and breeding success rates of
seabirds.
For more information, see
Environment Canada’s Green Lane at
www.ec.gc.ca/climate/ccs/index.htm
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