Published by Australian Academy of Science
Impact of global warming on biodiversity Box 1 | Giant problem for pygmy possum

Even a modest amount of global warming might be enough to reduce the snow cover to such an extent that the survival of the mountain pygmy possum will be in jeopardy. Already threatened by the development of ski fields, bushfires and feral predators such as cats and foxes, the mountain pygmy possum is known to exist in only three genetically distinct populations, over an area of 10 square kilometres, in the NSW and Victorian Alps. Its ability to hibernate during winter is an important element of its survival; the energy it saves probably gives it a competitive advantage over non-hibernating species in areas with seasonal snow cover.

However, with global warming, the extent of snow cover in Australia is predicted to decline dramatically. Even today it comprises only 0.15 per cent of the continent, an area that could decrease by 39 to 96 per cent by 2070. An average temperature rise of only 3ºC would entirely eliminate snow from all Australian mountains. Scientists predict that a loss of snow cover would increase winter mortality of the species, because of decreased insulation and a reduction in the availability of suitable habitat. Moreover, the breeding grounds of one of the possum’s most important food sources, the Bogong moth, could be affected by increased drought due to global warming. The net effect would almost certainly be an increase in the vulnerability of the mountain pygmy possum to extinction. Already there is evidence that annual snow cover is decreasing; for example, a strongly decreasing trend has been detected at the Spencers Creek snowfield between 1959 and 1999.

Other alpine species are at risk: one study estimated that nearly half the 190 alpine plant species on Mt Kosciuszko are vulnerable to global warming.

Related sites

• Mountain pygmy-possum – Burramys parvus (Australian Government Department of the Environment and Water Resources)

• Possum dreaming (Australian Broadcasting Corporation)

Box 2. Responses to global warming