Climate and weather of the Australian Alps

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CLIMATEAND WEATHERTheweather inthe pastOver many millions of years, the climate of Australia has changed many times. Sixmillion years ago rainforest covered much of Australia, including the Alps. Three millionyears ago colder conditions with increased rainfall dominated. Vast cold, treeless plainsreplaced the rainforest vegetation and the alpine plants and animals started to colonisethe area. In the last two million years the area was covered by ice several times. In theglacial periods, the species of plants and animals that could withstand the cold, spreadout over the land. As these periods ended, these species retreated back to the only areawhere it was still cold – the Australian Alps. These plants and animals had special characteristics,which species today still demonstrate, to cope with the wide temperaturevariations. The last Ice Age ended only 10,000 years ago.ClimatechangeIncreases in temperatures around the world due to the greenhouse effect will have significantimpacts on the Australian Alps. The global average temperature has increasedby approximately 0.6 °C in the past 100 years and is predicted to continue to rise. Anaverage global warming of 0.7 to 2.5 °C is predicted by 2050 and 1.4 to 5.8 °C by 2100.Climate change may cause a dryer, hotter climate, less snow and more frequent and extremefire and weather events in the Australian Alps. Warmer temperatures that lengthensummer, or result in warmer autumns and winters, mean less snow will fall. The bestcasescenario for snow is the least increase in temperature and the greatest increase inwinter precipitation. Even a modest warming of 0.6°C by 2050 will result in a reductionof 15 to 20 days of snow cover in the Australian Alps.The naturalGreenhouseEffect.Some of the sun’s radiationis reflected back into spaceby the atmosphere, cloudsand the earth. 51% passesthrough the atmosphere andwarms the earth’s surface.Some of this warmth escapesas infra-red radiation. Gasesin the atmosphere, like watervapour, Carbon Dioxide,Methane, Chlorofluorocarbons,Halons and NitrousOxide absorb and re-emitsome of the infra-red, effectivelywarming the loweratmosphere and earth byabout 35The enhancedGreenhouseEffect.An increase in thequantity of Greenhousegases as a result ofhuman activity, mayincrease temperatures.EDUCATION RESOURCE CLIMATE AND WEATHER 4/7
CLIMATEAND WEATHERChanges in: Low impact 2020 High impact 2020 Low impact 2050 High impact 2050Temperature +0.2°C +1.0°C +0.6°C +2.9°CPrecipitation +0.9% -8.3% +2.3% -23%Snow cover (days) -15 to 20 -100Climate Changescenarios forAustralian Alps.(Source: Hennessy et al 2003)Climate change will mean changes to habitat and therefore changes to the diversityand abundance of plants and animals. These changes will be particularly severe in theAustralian Alps where there is only a small area of true alpine habitat and, therefore,limited high altitude refuge.With less snow, and the soil becoming warmer, the higher elevations without treeswill become more suitable for lower altitude plants including trees. In other words, thealtitude at which trees and other plants can grow will be higher and trees may alsocreep into sub alpine frost hollows. It is highly likely that in the future the treeline maymove upwards and that new species will survive. As the tree line advances upwards,the alpine habitats will become smaller, thereby reducing the endemic alpine plants andanimals to even smaller areas of suitable habitat. Australia’s true alpine habitats mayeventually disappear as the climate continues to get warmer.It is predicted that there will be both good and bad impacts on the flora. On the plusside its likely that there will be increases in the occurrence and distribution of severaldominant plant communities at higher elevations including Alpine Herbfield, Heathlandand Tussock Grassland. However, there may also be decreases in more sensitive communities,particularly Short Alpine Herbfield and the Alpine Bog - communities that areparticularly important for water storage. Predictions have also been made that climatechange will contribute to an increase in the distribution and diversity of weeds in thesubalpine and alpine areas of the Australian Alps, placing further pressure for resourceson endemic species.The numbers of different species of birds at specified altitudes may increase with increasedwarming and it is predicted that global warming will have significant impacts onthe distribution and numbers of the alpine, endemic Mountain Pygmy Possum (Burramysparvus) and the Broad-toothed Rat (Mastacomys fuscus). However, more research isneeded to understand the potential effects of climate change on other animals andinvertebrates in the Australian Alps.A reduction in snowfall and cover may have a big impact on the recreational activitiescurrently enjoyed by many Australians. Since less snow cover could have affect theeconomic viability of ski resorts, the resorts have been increasing snow making facilitiesas well as increasing year-round recreational opportunities such as guided activities,music festivals and other non snow recreational facilities.Management agencies for the national parks of the Australian Alps acknowledge thechallenges of managing for climate change and have committed to supporting researchand monitoring to assist in the on-ground management of those species and communitiesconsidered to be at risk from climate change. Furthermore, agencies are committedto undertaking operations and developments to reduce greenhouse gases and ameliorateclimate change.EDUCATION RESOURCE CLIMATE AND WEATHER 5/7
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Climate and weather of the Australian Alps

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