Climate Change is the change in climate over a time period that ranges from decades to centuries. The term refers to both natural and human-induced changes. The term "climate variability" refers to shorter term (years to decades) fluctuations in climate. Climate Change is usually addressed on a global scale; Small changes that only occur in a small area could be overlooked in the big picture. Change that occurs in a region can be significant in a short period of time. Changes in regional climate patterns may have positive and negative effects on these important ecosystems and resources.

Bringing it back to Canada

An analysis of temperature records shows that the Earth has warmed an average of 0.6°C over the past 100 years. There appears to have been a warming until the early 1940's then a moderate cooling until the mid 1970's, followed by a renewed and pronounced warming continuing through the present. The 1990's was the warmest decade on record. (In fact, ice core and other proxy data indicates that the 1980's and 1990's were the warmest decades of the past millennium). (Green Lane, 2003)

Night-time temperatures over land have generally increased more than daytime temperatures. Regional changes are also evident. For example, recent warming has been greatest over the mid-latitude continents in winter and spring, with a few areas of cooling such as the North Atlantic Ocean. Precipitation has increased over land in high latitudes of the Northern Hemisphere, especially during the cold season.

This is consistent with predictions of climate change due to an enhanced greenhouse effect and increased aerosols. Yet, it could also be within acceptable limits for natural temperature variation.

Canada has warmed by 1.0°C over the last century. However this warming has not been consistent throughout the entire time span. The 1980's and 1990's were undisputedly the warmest decades on record in Canada. The warming that has been observed in Canada over the past century is real and significant though its intensity has varied from decade to decade, from region to region, and from season to season. (Figure at left and prose courtesy of Green Lane, 2003)

Climate Change in Northwest Territories
 
As the world warms, temperature changes will be greater in the north, and they will be greater in winter than in summer. By 2100, winters in parts of the Canadian Arctic are projected to be 5 to 7%C warmer than they are today.

The adverse consequences are expected to be particularly severe where the ecosystem is sensitive to climate and the traditional lifestyle is tied to the land. The North is already being affected by climate change: permafrost is melting, putting transportation routes, tailings ponds and buildings at risk; an increase in summer insects is threatening caribou and reindeer populations; and, the Arctic ice cap is thinning and has shrunk in area by some 15% (Environment Canada, 2003)

The best indicator for determining any short or long-term change in the climate for any region is a simple record on temperature. Climatologists have been adamant at recording temperature measurement for many different regions of Canada, including that of the Mackenzie District. The following figure shows the change in average temperature over Canada.

Different Factors affected by a change in temperature

The rest of the material presented here is meant to be a basic overview of several areas that can be affected by climate change. Any further inquiry can be conducted from the Links and Notes page.

Atmospheric Circulation
Back to the subject of circulation in the atmosphere, the subject of a change in the trend of Extra-tropical cyclones if of great interest. The extra-tropical latitudes of the northern hemisphere is where cold (north) and warm air (south) masses merge, usually resulting in an unstable environment in the air masses. Area of low pressure tend to form Cyclogenesis throughout the extra tropical regions. Cyclogenesis occurs during every month of the year. Significant formation almost always occurs during the late fall, winter, or early spring. These significant systems are responsible for large winter storms.

An aspect of the Mackenzie River Basin- River Ice
River ice is a unique aspect of Canadian Hydrology. All rivers experience some ice effect, yet in some instances, runoff events associated with river ice have produced extreme and dangerous flooding events. River Ice interacts and obstructs the passing of floods. The blockage causes water levels far higher than those experienced for the same flows under open water conditions. The following are pictures provided by the Makenzie GEWEX study (MAGS) for river ice research conducted upon the Athabaska River.
These photos are meant to just convey the potential short-term natural hazard that a shift in temperature variability may lead to in a river such as the Mackenzie.

The phenomenon of River Ice- induced flooding is something to keep in mind for the construction of large scale projects such as the Mackenzie Gas Pipeline near the Mackenzie River.

Permafrost
50% of the Canadian land surface is underlain by permafrost. A significant portion of the permafrost has an average temperature that is warmer than -2°C, permafrost threshold temperature. With climate warming, this warmer permafrost may ultimately disappear Thawing of ice-rich permafrost may present hazards to infrastructure, and may also increase landslide activity.  Increased thaw settlement may occur beneath buildings, utility systems, roads, railways, and pipelines.
Permafrost is a thermal condition and therefore its occurrence is dependent on climate.

The Mackenzie Basin is prone to landslides. Most occur in areas of permafrost that contain Quaternary sediments. Landslides usually result from the melting of the ice and permafrost underneath the soil caused by :
Exposure of ice
Shoreline erosion
Fire
Abnormally high Precipitation Events

The Mackenzie River basin is very prone to landslides at any given time of the year. the tendency toward landslides in this region should be well-noted before the building of large scale projects such as the pipeline.