"General circulation models" (or GCMs) are three-dimensional, computerized
representations of the Earth's climate. While the various models are different,
all illustrate that significant climate change will occur. Scenarios developed
from GCMs show how the climate may change in response to varying levels of
GHGs in the atmosphere. These scenarios consider such factors as population
growth, economic activity and energy use. Parks Canada has developed scenarios
that apply from the regional scale down to individual parks. They cover time
periods of 20, 50 or 100 years into the future.
Carbon dioxide levels in our atmosphere may double this century. The global
average temperature may increase by as much as 5°C. The rate of temperature
change increases as one approaches polar regions. Thus, as a northern country,
Canada is particularly vulnerable. The result of this temperature change will
not simply be a more moderate climate. Instead, there will significant disruption
of ecosystems that have adapted to the existing climate.
Temperature changes in many of our national parks may be more than twice
the global average.
Over the next 100 years, these are the average temperature
increases expected in Canada's national parks. The ranges reflect various
- 2.2 -4.8°C for the parks in the Atlantic region
- 4.6-7.5°C in the Great Lakes region
- 4.4-10.5°C in the Prairies
- 4.3-7.8°C in the Western region
- 3.7-7.7°C for Pacific parks
- 5.6-11.5°C in the Arctic region
Precipitation is more difficult to model than temperature. However, we can
make certain assumptions. Warmer temperatures, especially in the winter, will
result in less snowfall and a reduced snow pack. This in turn would lower
lake and groundwater levels and reduce stream flows.