Big, dry and full: Population politics and the environment in Australia
The inexorable increase in human population size in recent decades has been accompanied by dramatic reductions in the population sizes of many non-human species and by the extinction of some 270 species of terrestrial vertebrates. Rates of loss are 1- 2 orders of magnitude greater than historical background levels for most groups. Birds and mammals top the list of species that are no longer with us, and provide insight into the key drivers of extinction: human overkill, loss of habitat, invasive species, and interactions between these processes and others such as pollution and disease; all processes are driven by human activity and intensify as our numbers grow. As human populations become more urbanised, two further processes occur: cultural loss of memory about the biological riches that have vanished, and diminishing connection with what is left.
In Australia, a largely arid continent apart from the eastern, south-eastern and south-western fringes, human population has grown from a pre-European (pre-1788) level of between 318,000 and a million, to the current 23.5 million, 89 per cent of which are urbanised. Taking Australian mammals as a case study, we suggest that—by 2100—increases in human population size, and anthropogenic climate change, will combine to exterminate many of the continent’s most charismatic species. Our natural systems will be homogenised and dominated by small generalist species. Unless strenuous efforts are made now to stabilise human numbers and impacts, a Down Under dystopia will be hard to avoid.