At the height of winter in many parts of the world, the ground gets covered with snow, while harsh temperatures and biting wind become the norm. It would seem to be an environment where very little life could actually survive. However, just below that snow cover, there is a microenvironment where a long list of essential plants and animals exist and thrive. According to a recent study and weather statistics from the past 40 years, this layer -known as the subnivium- is actually in a rapid and dangerous decline, as winter temperatures have gotten warmer and more irregular.
According to the official statistics, since 1970 the Northern Hemisphere has seen a snow cover decline of 3.2 million square kilometers, primarily during the key months of March and April. Life below the snow blanket is protected from harsh wind, while holding in warmth which radiates from the earth. In this warm protected place plants are able to photosynthesize, insects develop, and generally the groundwork for the coming warm seasons is laid out.
Some might think that a decline in snow cover simply means spring can start earlier, but researchers have observed that this is not what happens. Instead, many of these key processes below the snow cover don’t have time to take place. Temperature spikes, snow cover melts suddenly followed by sudden spikes of cold and more snow – leading some processes to start early and then be suddenly interrupted or stopped altogether. As an additional side effect, many species of animals that survive on the insects and plants of the subnivium, also face population decline and starvation.
In some parts of the world, human life has already been drastically effected by the degradation of the snow blanket. Nomadic herders of the Mongolian steppe have long survived the winter with their cattle by having them feed on organic material just beneath the snow cover. But the increasingly manic temperatures in the winter combined with extremely dry summers have left virtually nothing for their cattle to live off in the lean winter months. As a result, over the last few years cattle have been wiped out as has the ancient way of life of the nomads. Today the country suffers from a food crisis as nomads head to the capital with no food, no money, and no prospects of sustaining themselves. A humanitarian crises that began with the decline of the essential snow blanket microenvironment.
Photo: Chapendra / flickr
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