Climate Change in the Arctic - The Changing Arctic Environment: The Arctic Messenger - page 308

Phenology is the study of the relationship between the life cycles of animal and plant
species and the periodicity of cycles in their natural environment. When climate changes
rapidly, plant and animal species and communities can suddenly find that such relation-
ships are disrupted. For example, several climate-related stresses have been observed to
impact caribou and reindeer in the North American and Eurasian herds. We have already
encountered how intermittent winter freeze and thaw cycles can create a strong crust of ice
over vegetation. This makes it very difficult for caribou and reindeer to reach their winter
food plants. Robert Corell has told me that the Sami reindeer herders refer to this type
of snow/weather condition as goavvi . In these circumstances, herd losses of upwards of
50-75% have been observed.
Another worrying group of observations by indigenous peoples and scientists is called
trophic mismatch . Herds have evolved traditional migratory behaviours and pathways to
move from winter-feeding areas to calving grounds and to summer areas. The prime time
for feeding is when vigorous new growth is appearing on the shrubs. However, if snow
conditions prolong the first part of a migration pathway that involves crossing a river, the
herd may arrive at the river after ice breakup. This could lead to the significant mortal-
ity of calves as they try to cross. Exactly this scenario has been observed occurring with
the Porcupine herd as they cross the Porcupine River (north-western Canada). This river
is progressively breaking up earlier in response to regional warming. The compendium of
Krupnik and Jolly and the 2005 ACIA provides a comprehensive description of these types
of impacts. Caribou and reindeer are a vital source of food and clothing for Arctic circum-
polar indigenous peoples.
One of the big unknowns concerning potential changes in some terrestrial Arctic eco-
systems relates to the long-term availability of water. Much of the Arctic has little precip-
itation, particularly the Canadian Arctic, which comes as a surprise to some visitors when
they see the vast expanse of lake and muskeg. It is all a question of evaporation. In the
past, little snow or rain evaporated and permafrost inhibited drainage. But what will hap-
pen when a critical temperature is reached where evaporation and runoff exceed precipita-