Potential Impacts of Climate Change on the Hydrology of the Snowy Mountains - Term Paper Example

Running Head: Potential Impacts of Climate Change on the Hydrology of the Snowy Mountains Name: Lecturer: Course: Date: Table of Contents Table of Contents 2 Introduction 3 Decadal trends in temperature and precipitation 3 Scenarios 3 Causes 5 Comparison with other regions 6 Conclusion 11 References 13 Figure 1: Australian Alpine and subalpine areas (Gorman-Murray, 2008). 4 Figure 2: Indication of glacial retreat (UNEP, 2009). 6 Figure 3: Simulated Change in Snow Cover (Gorman-Murray, 2008). 9 Introduction Snow cover and its duration have a critical role in the amount of socio-economic and environmental systems in mountainous regions. The ways in which mountain glaciers and hydrological systems behave is closely connected to the volume and timing of snowfall and melting of snow (Whetton, Hayloc and Galloway, 1996). As a pointer of climatic change, snow is in fact an interesting variable since it relies on temperature and precipitation (Beniston, 1997). This report examines decadal trends in temperature and precipitation, the methodologies used in collecting local and regional scale climate information for the Australian alpine catchment and lastly, the projected impacts of changing temperature and precipitation on flora and fauna Decadal trends in temperature and precipitation Scenarios The alpine environment in Australia is made up of nearly 0.2 percent of the total land mass. The region is located along the southeastern mountain ranges of Victoria, New South Wales and the Central Plateau of Tasmania. Figure 1: Australian Alpine and subalpine areas (Gorman-Murray, 2008). The Australian Alps has been identified as vulnerable to impacts of climate change. Findings by Sanchez-Bayo and Green (2013) suggest that the average dept of snow in mountainous regions of southeastern Australia is lessening at a rate of 0.48 cm a-1. At the same time, the duration of the snowpack has decreased y 18.5 days since 1956, accounting for -3 days per decade. Researchers have shown that snow is temporarily and spatially limited in Australia in comparison to South and North America and Europe (Whetton, Hayloc & Galloway, 1996). Nearly 0.15 percent of the Australian continent receives regular winter snow falls. The most extensive snow covered areas are situated in the southeast of the continent in the Snowy Mountains in New South Wales (nearly 2500km2). Of this, some 1200 km2 receives around 60 or more days of snow cover and about 250 km2 (representing 0.0001 percent of Australia) is Alpine (Pickering, 2007). The annual average precipitation has reduced significantly over most of eastern Australia since the 1950s. This has led to a decrease over the Southern Alps as well as an increase in the Northern Alps. Because of this, the impacts of global warming on the alpine precipitation as well as on the flora and fauna have become among the first quantifiable indicators of climate change (Pickering, 2007). Causes The snow cover in the Australian region varies significantly in duration and depth from year to year (Whetton, Hayloc and Galloway, 1996). The variations are attributable to changes in the occurrence of snow-bearing synoptic circulation systems. They are also attributable to the prevalent seasonal precipitation as well as temperature anomalies that partly reflect certain synoptic systems that occur (Beniston, 1997). The major factors responsible for such declines include; increasing temperature trends of 0.36 °C each decade, as well as a reduction in precipitation during winter at a rate of 10.1 mm a-1. Given that the snowpack depth depends on precipitation trends and minimal temperatures (multiple r 2= 0.43), the reduction in the length of the snow period is best forecasted by reduced humidity and increased temperatures (Pickering, 2007). The cause of the warming trends includes greenhouse gases (GHGs), in specific water vapour and atmospheric carbon dioxide. In any case, the decrease in winter precipitation appears to not to be related to the forcing of the GHGs. Rather, it is associated statistically with the Southern Oscillations Index (r = 0.38) (Sanchez-Bayo and Green, 2013). Comparison with other regions Some studies have established that snow will become rare and below some 1500 to 2000 metres altitude in the Swiss Alps. Projects indicate a 3 to 5 degrees Celsius increase in temperature. An increase in seasonal precipitation is projected to be between 5 to 20 percent (UNEP, 2009). The same can be said of the Himalayan glaciers, which have been shrinking over the past 5 decades. Unlike in the Australian and Swiss Alps, the degree and nature of shrinkage had remained unchanged over the last 100 years. In any case, the temperature increase for the Himalayan region has been greater than the Australian, Chinese Nepal and Swiss Alps average of 0.75 degrees Celsius (Fig 1). However, glacier has generally increased in the four areas, as well as by 50 percent in northern Afghanistan and 30-35 percent in Pamir (UNEP, 2009). Figure 2: Indication of glacial retreat (UNEP, 2009). Monitoring change in the alpine climate Eddy covariance (EC): Eddy covariance is the most direct approach used in quantifying the biosphere atmosphere of energy and mass. It is a critical tool for understanding how the biosphere responds to atmospheric forcing in addition to the role that biosphere plays in modulating climate. EC method is often applied in surface layer, with scalar concentration and wind speed measurements that have been made using fast sensors at great temporal resolution to capture turbulent fluctuations that carry a significant fraction of the flux (Hörtnagl et al, 2010). GLORIA's Multi-Summit approach (short for the Global Observation Research Initiative in Alpine Environments approach) is a method for monitoring change in the alpines. Its purpose is to establish long-term observation network for comparative study of climate change impact on the biodiversity of the alpine areas. The method is universally applicable to a range of alpine environments, including tropical latitudes to polar environments. In Australia, Multi-Summit sites have been initiated in 18 alpine regions across the continent. Basically, it monitors the risk of biodiversity losses as well as the vulnerability of high mountain ecosystem during climate change (Hörtnagl, et al (2010). Satellite temperature measurements: although weather satellites do not measure temperature directly, they measure radiance in several wavelength bands. The measurements can be applied to monitor global climate. Satellite data can display evidence on factors such as downsizing and it impact on glacier loss. The satellite-based observations are used for several tests across the entire Australian Alps (Paul, Kaab and Haeberli, 2007). Empirical Permalp/Permakart method: Permakart model refers to an empirical-statistical method that utilizes the observed relationships relationship between the climate that influences the occurrence and the topography of the Alpine permafrost. Basically, it measures permafrost distribution in the alpine regions (Schoner, et al 2012). Predicted impacts Climate change situations for the Australian Alps are based on the CSIRO temperature and prediction models for 2001 (See Table 1). Table 1: Best and worst case climate change scenarios for the Australian Alps as predicted change These predicted climate changes are likely to have dramatic effects on the natural values of the Australian Alps. Because of these values, the shift in temperature of +0.6o C under minimal impact scenario and +2.9o C under a maximal impact scenario by 2050 are predicted (Fig 3). Figure 3: Simulated Change in Snow Cover (Gorman-Murray, 2008). Further, the resulting reductions in the snow cover that result from the shifts in precipitation and temperature in both scenarios are expected to be dramatic. The worst expected scenario is expected to be a 6 percent reduction in the area that witnesses more than two months snow cover per year. Such forecasts have significant implications for ski resorts, with expected reductions of between 30 and 40 days in the average season length by the year 2020. Under expected worst scenarios by 2050, more dramatic reductions are predicted in season duration by about 100 days. The highest ski resorts are expected to have season durations of over 10 days (Whetton, Hayloc and Galloway, 1996). In the case, of highest peak in the Australian Alps, the forecasted changes in climate include shifts in the snow cover by about 183 days to 96-169 days by 2050. More dramatic changes in the peak snow depth are expected from over 2 metres to less than 50 centimetres under the worst case scenarios by the year 2050. Alternatively, the change can be viewed by considering that +2.9oC is almost the equivalent of a 377 meters upward shift in the snowline. Further predictions depict that the temperature increase 3 degrees Celsius, could change the climate of the area that is presently alpine to subalpine. This will result in the loss of rare species such as groundwater communities like peatland, bogs, fens and feldmark (Pickering and Green, 2008). Increased temperatures and decreased snow cover is predicted to result in changes in richness of species in the Australian Alps. The richness of plant and animal species is correlated to altitude in mountain regions globally (Table 2). Table 2: Effects of Climate change globally In the mountainous regions, there is a general trend of decline in exotic and native plant diversity as well as increased proportion of the biota that is endemic with increased altitude. For instance, in the Australian Alps, snow cover will strongly affect the distribution of bird species and mammals (Whetton, Hayloc and Galloway, 1996). Pickering and Green (2008) disclose that already evidence suggests some changes in the timing of migration and altitudinal extent in the mountains from the lowlands because of reduced snow cove in the Australian Alps. For most species, a gradual change in distribution is expected. However, for others, there is an underlying risk for some mammal populations that the process is likely to be dramatic and rapid. This is likely to happen where climate change results in dissociation in timing of the key events for the species In the case of endangered broad-toothed rat, it seems to be the timing of the thaw as well as the increased risk of cold conditions of post snow melt. Changes in the distribution of vegetation communities are also expected. It may involve variation in the tree line in the frost hollows as well as between the alpine and subalpine regions (Pickering and Green, 2008). A likely change in the distribution of specialist communities is also expected as well as in communities that depend on snowmelt such as fens and bogs. In the case of plants, changes in distribution may be evident in the short-term even as others may be masked. Since many alpine species include long-lived perennial, there may be dramatic reductions in the size of the populations as well as in the cessations of recruitment for many populations. However, a few long-lived individuals may survive for longer periods (Pickering and Green, 2008). This may mask the functional loss of the species. Conclusion Climate change in the region is characterized by varied ranges of potential impacts on the Australian alpine and subalpine species that is controlled by temperatures that are specifically sensitive to climatic changes. Alpine temperature data of the area over the last three decades indicates that the warming trends are somewhat greater at higher elevations. It is therefore more likely to significantly impact the ecological diversity of sensitive environments, as well as the associated human activity in the region. References Beniston, M. (1997). "Variations Of Snow Depth And Duration In The Swiss Alps Over The Last 50 Years: Links To Changes large-Scale Climatic Forcings." Climatic Change 36: 281–300 Beniston, M. (2013). "Is snow in the Alps receding or disappearing?." WIREs Clim Change 10: 1-10 Gorman-Murray, A. (2008). "Before and after Climate Change: The Snow Country in Australian Imaginaries." M/C Journal, Vol. 11, No. 5. Retrieved: Hörtnagl, L., Clement, R. Graus, M. et al (2010). "Dealing with disjunct concentration measurements in eddy covariance applications: A comparison of available approaches." Atmospheric Environment 44: 2024-2032 Paul, F., Kaab, A. & Haeberli, W. (2007). "Recent glacier changes in the Alps observed by satellite: Consequences for future monitoring strategies." Global and Planetary Change 56: 111–122 Pauli, H., Gottfried, M., Hohenwallner, D., Reitter, K. & Grabherr, G. (2004). The GLORIA Field Manual – Multi-Summit Approach. Luxembourg: European Communities Pickering C. (2007). Climate change and other threats in the Australian Alps. In: Protected Areas: bufering nature against climate change. Proceedings of a WWF and IUCN World Commission on Protected Areas symposium, 18-19 June 2007, Canberra. (eds M. Taylor & P. Figgis) pp. 28-34. WWF-Australia, Sydney. Pickering, C. & Green, K. (2008). Vascular plant distribution in relation to topography, soils and micro-climate at five GLORIA sites in the Snowy Mountains Australia. Jindabyne: National Parks and Wildlife Service Sanchez-Bayo, F. and Green, K. (2013). "Australian Snowpack Disappearing Under the Influence of Global Warming and Solar Activity." Arctic, Antarctic, and Alpine Research 45(1):107-118. Schoner, W. et al (2012). "Spatial Patterns of Permafrost at Hoher Sonnblick (Austrian Alps) - Extensive Field-measurements and Modelling Approaches." Australian Journal of Earth Sciences 105(2): 154-168 UNEP (2009). Recent Trends in Melting Glaciers, Tropospheric Temperatures over the Himalayas and Summer Monsoon Rainfall over India. Nairobi: United Nations Environmental Programme Whetton, P., Hayloc, M. & Galloway, R. (1996). “Climatic Change and Snow-cover Duration in the Australian Alps." Climatic Change 32: 447-449 Read More