The term "cryosphere" traces its origins to the Greek word 'kruos' for frost. It is defined as the portion of the climate system consisting of the world's ice masses and snow deposits including snow, solid precipitation, permafrost and seasonally frozen ground, ice sheets, ice caps and glaciers, sea-, river-, and lake ice.
The cryosphere is an integral part of the global climate system with important linkages and feedbacks operating through its influence on energy, moisture and gas fluxes (see Figure 1 below). Large areas of the cryosphere exist at temperatures close to melting and, as a result, are very sensitive to changes in temperature. This is a significant fact since much of the global cryosphere is located in high latitudes where enhanced warming is projected by climate models.
Within Canada, the cryosphere is among the most important features of the physical and biological environment with most of the country experiencing several months of snow cover each winter, more than half being covered by the permafrost zone, and many of our navigable waters affected by ice. Furthermore, our terrestrial ice masses constitute the most extensive permanent ice cover in the Northern Hemisphere outside of Greenland, and in the western cordillera, glaciers are a significant component of the mountain hydrological system.
Monitoring and understanding the cryosphere is required to address key science questions such as the contribution of glacier and ice sheet melt to sea level rise, and for improved representation of cryospheric processes and feedbacks in climate and hydrological models. There are also ongoing domestic requirements for monitoring the cryosphere in Canada for operational decision making, and for understanding its response to warming and the impacts on our ecosystems and economy. The later is particularly pertinent since a wide range of Canadian activities are sensitive to variations in cryospheric elements (e.g. agriculture, transportation, construction, mining, offshore oil exploration, recreation).
The relationship between the global climate system and the cryosphere is a complex one that contains numerous linkages (see Figure 1) and feedback mechanisms. A feedback mechanism is defined as a process that changes the sensitivity of the climate response. One of the most important feedback processes involving the cryosphere-climate system is the snow/ice-albedo feedback. Snow and ice have a much higher surface reflectivity (albedo) than most other natural surfaces (70-90% versus 15-20%), so changes in the area of snow and ice on the planet results in a positive feedback with the global climate system i.e. as the area of snow and ice decreases in response to an intitial warming, more inoming solar radiation is absorbed which results in warmer temperatures.
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Figure 1: Diagram showing the numerous feedback mechanisms and relationships between the cryosphere and the global climate system. Source: G. Flato, EOS Science Plan, 1999.
The Intergovernmental Panel on Climate Change (IPCC) expects that global warming and climate change will lead to pronounced reductions in seasonal snow cover, permafrost, glacier and periglacial belts of the world. Because the cryosphere is so intimately linked to society, economy and fabric of Canada, these changes can be expected to have widespread and significant impacts across many regions of the country.
The results of the research being carried out by CRYSYS will contribute to new techniques for remotely-sensed monitoring of the cryosphere from space (including Canada's RADARSAT satellite), and to improved understanding and modelling of cryospheric processes, variability and change in Canada and throughout the world.
To learn more about each cryospheric component, choose one of the following options:
The Green LaneTM,
Environment Canada's World Wide Web Site.
