Desertification and climate change—the Australian perspective

In Australia, desertification tends to be associated with land degradation in the range- lands. It results from unsustainable land use and the impact of European settlement, rather than chang- ing climate. Desertification can, however, be exacerbated or triggered by climate variability. Some of the degradation occurred in the early stages of pastoral development but the problem has continued. The extent of degradation has proved difficult to assess but survey results show it varies in severity across the country. Grazed rangelands have been most severely affected but the problem extends out- side the pastoral zone due to the impact of feral animals and changed fire regimes. Biodiversity has also been affected with extinctions occurring among small and medium-sized mammals. Climate change scenarios suggest shifts in rainfall patterns but the major impact will come through increased variabil- ity. Substantial shifts in rainfall have occurred over the last 100 yr with wetter periods generating unre- alistic expectations about land use and drier periods triggering land degradation. However, pastoral management is focused on short term climatic variability since this is what dominates both production and income. Policy responses require that the whole issue of sustainable land use be addressed rather than climate issues alone.