The Climate is Changing!
New climate projections for Australia were released in October 2007 by the CSIRO and the Bureau of Meteorology. “Climate Change in Australia” is a major report providing the latest information on observed climate change over Australia and its likely causes, as well as updated projections of changes in temperature, rainfall and other aspects of climate that can be expected over coming decades as a result of continued global emission of greenhouse gases. The new projections are based on 23 climate models and are the most detailed and comprehensive produced in Australia to date.
For the NT, the report shows that average annual temperature increases of up to 1.2 0 C have occurred in the Territory since 1910. Projections show that by 2030 annual average temperatures over the NT are projected to increase by a further 10 C – 1.2 0 C relative to recent decades. Small increases in average temperature can lead to very significant increases in the frequency of extreme events such as extreme rainfall events, fires and heatwaves. For example, the number of very hot days per year over 35 0 C in Darwin (currently 11) is projected to rise to 44 by 2030, and up to 227 by 2070. Changes to rainfall remain ambiguous for the Top End, while decreases in rainfall are generally projected for Central Australia. Increased intensity of tropical cyclones is likely, inundation from storm surge is projected to increase, and global sea level rise is projected to continue. More detailed information is available at www.climatechangeinaustralia.gov.au.
Impacts of Climate Change
There are a number of potential impacts resulting from climate change for the Northern Territory which need to be considered in developing adaptation strategies. These impacts are likely to affect natural and agricultural ecosystems and human health.
The effects of climate changes on natural and agricultural ecosystems are difficult to determine. Increases in atmospheric carbon dioxide levels can increase plant growth, provided water is in adequate supply, however, this effect decreases with increasing temperature. Similarly potential benefits of increased rainfall can be offset by increased evaporation rates.
The ability of pests and weeds to survive winters is expected to increase and the development of summer pest species is expected to accelerate with increased temperatures. Warmer temperatures would allow tropical diseases to spread southwards. It is possible that some sub-tropical weeds would benefit directly from climate change and indirectly from reduced competition from native species.
Global warming is likely to have both direct and indirect impacts on human health. Direct effects include heat stress and potential injury from cyclones and floods. Indirect effects include increases in mosquito-borne diseases such as dengue fever, and water-borne diseases such as giardia. Mosquito-borne disease infection is likely to increase as warmer conditions would extend the range and breeding season of mosquitos.
Although predicted temperature increases may appear slight, small changes in long-term average temperature are critical. For example, the global average temperature was only 8-10 degrees cooler during the last ice age. Even near term climate projections may change the species composition of some animal and plant communities. In general, the most adaptable species will dominate altered ecosystems. Warming temperatures may be particularly threatening to species in Northern Australia. Elsewhere in Australia, species may be able to migrate south to cooler climates. However, for species in Northern Australia, gradual southward migration into cooler regions may be prevented by the lack of water and associated habitat inland.
Human adaptation to climate change and increasing temperatures in the Northern Territory is likely to include increased usage of air conditioning with associated increased electricity use and greenhouse gas emissions. Adapting to increased temperatures by improving building design and increasing air conditioning appliance efficiency will assist in abating greenhouse gas emissions.
Although climate change presents many negative impacts, limiting greenhouse gas emissions and adapting to climate change also potentially provide unique opportunities for the Northern Territory. Some benefits of preparing for future climate change include:
- Cost savings for government, industry and the community as a result of greenhouse driven improvements in areas such as energy efficiency and cleaner production;
- Economic opportunities in new areas including renewable energy products and service delivery, energy efficiency and projects to sequester carbon;
- Improvements in public health through indirect improvements in air quality related to bushfires.
The NT may be relatively well placed to deal with climate change due to the existing natural climate extremes. For example, natural and managed ecosystems are tolerant of extended wet and dry conditions and existing infrastructure has been designed to minimise the impact of storms, cyclones and associated storm surge. Research into salt-water intrusion into the Mary River wetlands (pdf 3.5Mb) may provide insight into the impact of sea-level rise on the vast freshwater wetlands of Northern Australia. In Central Australia, planning for increased rain events will assist Government and the community adjust to climate change.
Long term planning for future social and environmental requirements will require innovative and cooperative approaches between government and the community. Government believes that assessment of the NT’s vulnerability to global warming is necessary in order to plan for adaptation to climate change.
