Climate Change and the Rocky Mountains - Impact of Global Changes on Mountains: Responses and Adaptation - page 433

INTRODUCTION
For at least half of the year, the whole of the Rocky Mountains are shrouded
in snow that feeds a multitude of glaciers. Snow and ice melts into rivers
that have eroded deep valleys with rich aquatic and terrestrial ecosystems.
The Rocky Mountains are the major divide on the continent. Melt water
from a multitude of glaciers, snowfi elds, and rainfall feeds major river
systems that run to the Pacifi c, Atlantic and Arctic oceans. The Rockies
truly are the water tower for much of North America, and part of the Alpine
backbone of North and South America. But for purposes of this chapter, we
consider the Rocky Mountains of the Canadian provinces of Alberta and
British Columbia, and the states of Montana, Idaho, Wyoming and Colorado.
The altitude of the Rocky Mountains condenses the weather, climate
and ecosystems of thousands of kilometers of latitude into very short
vertical distances. On a good day, a strong hiker can journey by foot from
the mid-latitude climates of the great plains of North America to an arctic
climate near the top of Rocky Mountain peaks—ecologists refer to the
bio-climate zone above tree line as alpine tundra since it bears such
similarities to the tundra ecosystem of the far north. Rapid changes in
elevation typical of mountain terrain create some of the most diverse
ecosystems in the world, but it is those rapid changes in microclimate
and ecology that make mountains sensitive to climate change. The energy
budget in mountains varies dramatically not only with elevation but with
slope and aspect. A modest change in the slope of the terrain over short
distances may radically change the solar radiation available in that location.
Shaded or north facing slopes have very different microclimates than the
same elevations in a sunlit location, or for a hill slope facing south. The
complexities associated with the diverse mountain terrain of the Rockies
compound complexities of weather and climate and create diverse, amazing
ecosystems, which are home to a diversity of plant and animal species that
have adapted to persist in these changing environments for millennia.
The discussion in this chapter addresses the impacts of climate change
in the Rocky Mountains. Climate change is real and ever present, and the
role of each of us in changing the climate is also real and present. The Rocky
Mountains are a vast and complex region that is valuable both for resources
and ecosystems. The Rockies cannot provide the valuable resources we
need and treasure, particularly clean plentiful water, unless we protect and
conserve mountain ecosystems. Hopefully the discussion in this chapter of
the major changes ongoing in the Rocky Mountains due to climate change
will help understand the impacts of climate change and add to the collective
will in society to minimize this change in future.