Addressing the realities of climate change

The impacts of climate change will be felt globally over the next century, according to the August 2003 issue of Austral Ecology " for the Ecological Society of Australia, published by Blackwell Publishing.

Associate Professor Lesley Hughes from the Department of Biological Sciences at Macquarie University, Sydney, has addressed this by conducting a review of observed and potential impacts of climatic changes on Australian species and natural ecosystems.

Although Australia is one of the world's highest producers of greenhouse gases on a per capita basis, it produces only just over 1% of global emissions. Therefore reduction of Australian greenhouse gas emissions will not significantly alter the impact of climate change unless the rest of the industrial world follows suit.

Consistent with global trends, Australia has warmed ~0.8°C over the last century with minimum temperatures warming faster than maxima. Current Australian policies regarding this issue are largely focused on mitigation strategies " developed in response to international pressure and the economic significance of future carbon trading.

Findings on the trends in Australia's climate and its impacts as published in this study include:

• Increased severity of coral bleaching and mortality in the Great Barrier Reef;
• Decline of snow cover and duration in the Australian Alps;
• Projected increases in annual average temperatures of 0.4 " 2.0°C by 2030 and 1.0 " 6.0°C by 2070;
• Possible contraction or fragmentation of species' current ranges;
• Negative impacts predicted for most vegetation types, with the bioclimates of some plant and animal species set to disappear entirely with a mere increase of 0.5 " 1.0°C of warming;
• Some species and natural ecosystems in Australia are already responding to the relatively modest warming that has occurred over the past century, consistent with responses of species and ecosystems elsewhere in the world. These responses include physiological, behavioural and distributional changes.

"Climate change as a result of the enhanced greenhouse effect is no longer a hypothesis but a reality. The recent global warming trend is now acknowledged by all to have been to be due to the increases in greenhouse gas concentrations " leading to significant impacts on species and ecosystems," Hughes noted.