Projected Climate Change and Variability and Their Impact on the Canadian Rocky Mountains - Impact of Global Changes on Mountains: Responses and Adaptation - page 410

Increased streamfl ow and retreating glaciers (exposing thitherto unexposed
ground) can lead to an increase in downstream fl ooding, sediment transport,
increased erosion (e.g., land slides) and change in water quality (Moore
et al. 2009). These changes in streamfl ow regimes have signifi cant socio-
economic and ecological impacts. Water resource is essential for such
activities as hydroelectric power generation (e.g., Columbia River) and
agricultural production.
Impact on ecosystems and socio-economic activities
Signifi cant changes in the existing climatic conditions will alter the complex
interaction between the 'natural' environment and human socio-economic
activities, such as agriculture, forestry and tourism. Hydrological cycle in
terms of water supply and demand will mediate that interaction in many
mountain regions.
Sensitivity of potential effects of climate change on water resource
for crops in the Okanagan Basin in the interior region of British Columbia
was studied by Neilsen et al. (2006). The Okanagan Valley is located in the
southern interior of British Columbia, its mild and dry climate infl uenced
by the rain shadow effects from the mountains on the west and a number
of lakes (Lake Okanagan being the largest in the valley). The agricultural
land usage is characterized by a complex distribution of orchards, vineyards
and pasture/forage. Okanagan agriculture is almost entirely dependent
on irrigation, drawing water from Okanagan River and lakes, tributary
streams and groundwater. Nearly 75% of the necessary water supply comes
from tributary streams (Neilsen et al. 2006). It is projected that by 2080,
the tributary streams will be reduced by roughly 15 to 30% of the current
fl ow. A combination of decreasing water supply and increasing demand
due to increasingly longer growing season (in addition to the demand
from increasing population) will increase the occurrences of drought and
thus put agriculture production in the Okanagan Valley at extreme risk.
Vulnerability of the grape industry in the Okanagan Valley is discussed by
Belliveau et al. (2006).
Another major impact of climate change concerns mountain ecosystems
and trees. Ecological systems in a mountainous region are sensitive to
climate change due to the existence of various species niches adapted
to corresponding microclimatic habitats produced by rapid changes in
temperature and precipitation regimes, both vertically and horizontally.
This produces high biodiversity, “often with sharp transitions (ecotones) in
vegetation sequences, and equally rapid changes from vegetation and soil
to snow and ice” (Beniston 2003). Luckman (1998) for example noted “small
but signifi cant vegetation changes … are taking place at upper econtonal
boundaries (where rapid step-like changes in vegetation types occur) in