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16 GLOBAL WARMING: CLIMATIC AND ATMOSPHERIC CHANGES

Figure 1.11 Atmospheric cooling factors. Courtesy of United Nations Environmental
Program/GRID-Arendal.

period of time that the Vikings crossed the Atlantic Ocean, 500 years before
Columbus, and settled in Greenland. On arrival, the Vikings found the land flourishing
with vegetation, caribou, and myriad other flora and fauna. Historical evidence
indicates that colonization and population of the new world continued to grow for
nearly three centuries, after which a new era of climatic change, referred to as the
little ice age, ushered in severe drops in global temperature. This resulted in a diminish-
ment of nourishment, leading to the eventual demise of the entire Viking settlement in
North America (Fig. 1.11).
Even though historical accounts and evidence substantiate global climate change,
climatologists and historians find it difficult to agree on the start and end dates of these
periods. All, however, concur that the little ice age began approximately around the
sixteenth century and lasted until the mid-nineteenth century.

DATING OF THE LITTLE ICE AGE

As mentioned earlier, there is mixed concurrence by scientists about the beginning
year of the little ice age. However, scientific discovery has shown that a series of
events preceded the downward trend of climatic conditions. It has been established
that in the thirteenth century, north polar ice and Greenland glaciers began advancing
southward. It also has been recorded that from 1315 through 1318, torrential rains ush-
ered in an era of extremely unstable weather conditions in northern Europe that lasted
through the mid-nineteenth century. The following is a timeline of climatic change
during the 400 years of the little ice age:

1250 Northern hemispheric pack begins to enlarge
1300 Northern Europe warm lasts a mere several years
1315 Profusion of annual rains devastates agriculture throughout Europe