In order to accurately track this development, the scientists record three parameters: the area of the snowcovered surface, the duration of the snow season, and the water equivalent, which is the amount of water stored in the snow.Īlthough there can be large differences in the individual parameters from year to year, scientists have observed some important trends in the Arctic that will become even more pronounced in the future: Smaller total area, earlier meltingĪs a response to the rising air temperatures, the total area that is covered by snow today is shrinking because snow is now falling in fewer areas than it did 15 years ago.
Researchers therefore note that, as a result of climate change, the snow conditions will change fun-damentally and in very different ways around the globe. The thickness of the snow layer as well as the duration of the snow season depend mainly on the air temperature and the amount of precipitation. In the Arctic, snow can cover vast landscapes for as much as nine months of the year. On the islands of the Canadian Arctic Archipelago, for example, snow banks feed small pools and wetlands with water well into the summer. In many regions of the world, and especially in the high Arctic, snow also acts as an important water reservoir. Ice floes with snow on their surface therefore grow much more slowly than bare ice. And if snow falls on new sea ice, the insulating effect can inhibit the transport of heat from the sea through the ice and into the atmosphere, and thus prevent freezing on the underside of the ice. In some situations, a snow cover that is too thick can prevent a permafrost soil that has thawed out in the summer from freezing deeply enough again in the winter. This property, however, also has disadvantages. The snow therefore not only protects the ice surfaces or permafrost soils below from the warmth of the sun, it also contributes significantly to the cooling of the polar regions.Īs a light and fluffy layer, snow insulates like a down jacket to protect plants, animals and the ground it covers from extreme cold. Compared to the bare glacier or sea-ice surfaces with reflectivities of 20 to 30 per cent, fresh snow reflects 80 per cent or more of the incoming sunlight.
Moreover, in the absence of snow there is little to fend off the sun’s energy. Where there is no snowfall, neither firn nor glacier ice can form. Snow is the basic building material for glaciers and ice sheets. This is somewhat unjust because, of all natural materials, snow not only possesses the best insulation and albedo properties, but its extent, volume and stability can also determine the fate of all of the other components of the cryosphere except for submarine permafrost – snow never comes into contact with the permanently frozen floor the Arctic shelf seas. In the public debate on climate change in the polar regions, snow generally receives little attention. Furthermore, all of these individual changes have direct consequences for the other components of the climate system, and the processes therefore amplify each other. The areas of sea ice and snow cover are shrinking glaciers are transporting their ice toward the sea more rapidly, causing them to lose mass and retreat landward the permafrost soils are thawing to greater depths for longer periods of time floating ice extending from the land, such as the ice-shelf regions in the Antarctic, are being destroyed by the heat. The bitter truth is that climate change has long since reached the polar regions, and it is now having a huge impact on all components of the cryosphere – the world of ice. It is all the more remarkable to note the strong words that climate researchers are now using to describe climate change in the polar regions. As a rule, scientists tend to concentrate rather on presenting new findings as objectively and dispassionately as possible. In science, data and facts are rarely presented in an emotionally charged way. These include snow, ice sheets and glaciers, ice shelves, sea ice, and the ice on rivers and lakes, as well as permafrost, which occurs both on land and on the sea floor. Cryosphere is a collective term for all of the components of the Earth System that contain water in its frozen form.
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