The climatic shift that was a major contributing factor to the collapse of the viking colonies is known as the

Greenland Norse collapse

Explanation:

The southern Greenland Vikings numbering 5000 at their peak never gave up their old way of lifestyle and did not adopt that of the Northern Inuits who arrived a century later after them. The study suspects that the climate factors became dominant and they were destroyed by the shifting nature of mother earth hence they starved to death and could not adapt to the present change in weather patterns this society collapsed. Some theories say soil grazing and over-exploitation of land lead to the effect of black deaths and the creation of ice age. It indicated that the number of fertile women dropped and thus population could not sustain itself.