Rising carbon dioxide will stimulate eucalypt growth, but this will entail reduced nutritional yield and higher levels of phenols which will doom Koala populations to slow death by starvation and extinction according to scientists. Other arboreal creatures like the greater glider, common ringtail possum, and common brushtail possum may also suffer the same fate.
Dr Ros Gleadow told a recent ABC Catalyst program "Leaves of plants grown at elevated carbon dioxide have a lot less protein. Wheat, barley, rice, all of those in probably only 50 to 60 years time will have 15 to 20% less protein in them than they do now." she said, "In about 50 years time or even 100 years time eucalyptus leaves will have trouble supporting arboreal herbivores like koalas because the phenolic concentration will be too high and the protein level too low."
The International Union for the Conservation of Nature (IUCN) included the Koala as one of ten iconic species under threat from climate change in a report released in Copenhagen in December 2009.
Professor Ian Hume from the University of Sydney released research in 2008 on the threats faced by Koalas, said "If there is a significant rise in CO2 concentration in the atmosphere, which we're already seeing, that's going to push the ratio of nutrients to anti-nutrients even lower by increasing the concentration of these carbon-based anti-nutrients.
"What currently may be good koala habitat may well become, over a period of not so many years at the rate that CO2 concentrations are rising, very marginal habitat… I'm sure we'll see koalas disappearing from their current range even though we don't see any change in tree species or structure of the forests." said Professor Ian Hume.
Is it possible for Koalas to adapt their diet to cope with climate change? Professor Hume commented "I don't think they've got enough time to do that, nowhere near enough time to do that."
The Koala is not presently on the endangered species list. The Australian Koala Foundation believes the wild populations have steeply declined in recent years from hundreds-of-thousands to as few as 43,000. The Threatened Species Scientific Committee is expected to make a recommendation in the middle of 2010.