Climate Change
Science
The global climate is changing and the world is getting hotter as the amount of carbon dioxide released into the atmosphere increases. The weight of scientific evidence presented by the Intergovernmental Panel on Climate Change indicates human activities are causing this change. In 2007 the Commonwealth Scientific and Industrial Research Organisation and the Bureau of Meteorology released a technical report on climate change in Australia. The report states:
- average temperatures in Australia 1910–2004 rose 0.9ºC
- since 1950 annual Australian rainfall has declined on the eastern seaboard and in the south, but increased in the northwest
- since 1973 droughts have become more intense.
Scientists have used icecores to piece together the history of the Earth’s climate. These icecores are time capsules unveiling atmospheric conditions prevelant thousands of years ago. They have shown that while climate variability is a natural process, humans are accelerating the rate of change through emitting greenhouse gases trapping the energy of the sun.
See Climate Change: How Will It Affect the Natural Environment in New South Wales? (PDF 1.20 Mb) for more details on climate change.
What Does This Mean for the Great Eastern Ranges?
Climate change is a threat to biodiversity. It is listed as a key threatening process in the Threatened Species Conservation Act 1995 and the Environment Protection and Biodiversity Conservation Act 1999. Climate change will adversely affect species by:
- changing the habitat in which animals and plants live
- promoting algal blooms growing in warmer water and competing with native fish for oxygen
- increasing temperatures – reducing snowfall in sensitive alpine regions
- increasing extreme weather events such as cyclones, thunderstorms and heatwaves.
Marsupials in the Great Eastern Ranges are descendants from ancient animal groups that appeared 20 million years ago. The rainforests of New South Wales are descendants of species that covered the Gondwana supercontinent 100 million years ago. Climate change could cause the extinction of species and end this link to the ancient past.
Some species are more at risk than others from climate change. For instance, the Sooty Owl (Tyto tenebricosa) depends on the rainforests and moist Eucalypt forests of the Great Eastern Ranges. Climate change will make these habitats drier and more vulnerable to fire. The Mountain Pygmy-possum (Burramys parvus) occupies a specific habitat in the Australian Alps – the greatest threat faced by this species is a reduction in snowfall brought about by increasing temperatures.
Climate change in the Australia Alps is better understood than in most areas of the Great Eastern Ranges. It can be predicted with greater confidence that the narrow climatic corridors will disappear with small temperature changes in a warming climate. The narrow climatic corridors of the Great Eastern Ranges are not restricted to the Australian Alps. It is estimated 25% of Australia’s Eucalypt species occur in areas where a small change in temperature could have a dramatic effect on their distribution.
The landscapes and ecosystems of the Great Eastern Ranges are stressed by human impacts. Habitat fragmentation and land clearing make it difficult for species to migrate, particularly those at the upper limit of their temperature range. The most vulnerable ecosystems include coastal ecosystems, alpine areas, rainforests, fragmented terrestrial ecosystems and areas vulnerable to fire.
The mountainous landscapes of the Great Eastern Ranges provide a wide range of habitats over the maximum elevation and latitudes, and connecting natural habitats over long distances. These habitats provide the best opportunities for Australia’s richest assemblage of plants and animals to find refuges, move, disperse and adapt as climate changes.
