Climate change implications

As noted above (Section 1.2) snow-cover extent and temperature are negatively correlated through the snow-albedo feedback mechanism, with the strongest feedbacks operating during the spring period. Chapin et al. (2005) showed that pronounced summer warming in Alaska was associated with a lengthening of the snow free season caused by earlier snowmelt. Satellite data suggest that Northern Hemisphere snow-cover extent has decreased by about 5% over the 1966-2004 period (IPCC, 2007), and climate model simulations for the next 100 years suggest an extensive northward retreat of NH snow cover, particularly over Eurasia (Fig. 1.4).

Climate warming impacts on snow cover (e.g. earlier spring melt, shorter snow-cover season, lower peak accumulations, and higher potential for rain-on-snow and thaw events) will have far-reaching effects on the natural and human systems described above. Shallow snow cover at lower elevations in temperate regions is the most sensitive to temperature fluctuations and hence the most likely to experience increased melt (Scherrer et al., 2004; IPCC, 2007). Changes to the snow cover and snow melt regime will have major implications for water resources (e.g. reduced

Figure 1.4. Comparison of mean March winter SWE (mm) simulated by the Canadian coupled global climate model (CGCM3) for the 1981-2000 "current climate" period (a) with simulated mean SWE for the 2081-2100 period (b) based on the SRES A2 emission scenario. Data courtesy of the Canadian centre for climate modeling and analysis. (Plate 1.4.)

Figure 1.4. Comparison of mean March winter SWE (mm) simulated by the Canadian coupled global climate model (CGCM3) for the 1981-2000 "current climate" period (a) with simulated mean SWE for the 2081-2100 period (b) based on the SRES A2 emission scenario. Data courtesy of the Canadian centre for climate modeling and analysis. (Plate 1.4.)

spring runoff, increased potential for evaporation) and water resource-sensitive industries such as hydro-electric power and agriculture (Barnett et al., 2005). IPCC (1998) provide an assessment of the impacts and vulnerabilities to changes in hydrology and water resources. In mountainous areas, for example, the snow line is likely to rise, but this may be partially compensated by higher precipitation above the freezing level. Ski resorts located in temperate mountain ranges (e.g. western North America, New Zealand, and the European Alps) already experience mean monthly winter temperatures that are only slightly below freezing, and any significant increase in air temperature will adversely impact the length of the ski season. In Austria, for example, it is estimated that an increase in temperature of

1.5 °C will shorten the ski season by about 15 days (Breiling, 1998). Scott et al. (2003) showed that improvements in snowmaking capacity reduced the vulnerability of the ski industry in southern Ontario (Canada) to the impact of warmer temperatures.

In summary, snow has substantial impacts, both positive and negative, on the natural environment and human activities. Documenting and understanding these impacts represents an important challenge, and one that is essential for adapting to a changing snow-cover climate.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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