Projected Climate Change and Variability and Their Impact on the Canadian Rocky Mountains - Impact of Global Changes on Mountains: Responses and Adaptation - page 404

(Snyder et al. 2003, Giorgi et al. 2001), a study carried out by Leung et al.
(2004) showed an increase in extreme precipitation of up to 10% for the
period 2040 to 2060 in winter, particularly in the northern Rockies. With
increases in temperature at higher elevations, the probability of rain-on-
snow events increases, resulting in an increase in extreme runoff causing
fl ooding downstream.
Simulating climate change and variability in mountainous regions is
a challenging task for climate scientists. Complexity of the mountainous
topography and surface characteristics can lead to a large spatial and
temporal variability in climatic regimes and responses. The density of
observations, in time and space, is nowhere near the required level to
describe accurately the rapid changes in meteorological variables such
as temperature and precipitation in a complex mountainous topography
that varies quickly in space. Not only do these changes occur horizontally,
but also vertically. It has been observed that climate response is elevation-
dependent (Rangwala and Miller 2012).
Although mountains constitute an important component of the climate
system, particularly in terms of the regional hydrological cycle, there have
only been few model simulations to examine how mountain regions will
respond to climate change, due mainly to the fact that the present global
and regional climate models do not possess suffi ciently adequate spatial
resolution to resolve the topographical details of the mountains, as well
as the detailed characteristics of the surface, such as various ecosystems
(vegetation, snow/ice, etc.), that are needed to properly represent such
important feedback mechanisms as snow/ice albedo feedback.
Climate Change and Variability in the Canadian Rocky
Mountains
As stated earlier, globally-averaged surface temperature rose nearly
0.5ºC from 1979 to 2010. It has been shown that a greater increase in daily
minimum temperatures at night than daily maximum temperatures during
the day has contributed more to the observed global temperature rise (Karl
et al. 1991, Easterling et al. 1997, Zhai and Pan 2003). There have been
several studies however, that suggest greater rates of warming have taken
place in mountain regions (as compared to lower elevation surfaces), with
temperature change as a function of elevation (Diaz and Bradley 1997,
Penderson et al. 2010).
Understanding how climate in mountain regions will change with global
warming is important because of its signifi cant impact on environment
(including humans) not just within the mountains, but also on lowlands
downstream where human population and socio-economic activities are