Climate change in Australia

Climate change has become a major scientific, economic, foreign policy, business, environmental and political issue in Australia in recent years.

Australia due to its heavy reliance on fossil fuels for electricity generation and transport has the ninth highest per capita greenhouse gas emissions in the world, Australia produces 1.4% of all greenhouse gas's produced worldwide, (559 Metric Tons in 2005), of these emissions, 74.3% is carbon dioxide, 20.2% is methane, 4.3% is Nitrous Oxide and 1.1% is HFC's and PFC's. All federal and state governments have explicitly recognised that climate change is being caused by greenhouse gas emissions. Sectors of the population are actively campaigning against new coal mines and coal fired power stations because of their concern about the effects of global warming on Australia, while other sectors of the population, however, believe it is still too early to tell whether or not there has actually been human induced climate change and believe the natural variability of Australia's climate too high for panic.

There is expected to be a net benefit to Australia of stabilising greenhouse gases in the atmosphere at 450ppm CO2 eq

Pre-instrumental climate change

Paleoclimatic records indicate that during glacial maxima Australia was extremely arid, with plant pollen fossils showing deserts extending as far as northern Tasmania and a vast area of less than 2 percent vegetation cover over all of South Australia and adjacent regions of other states. Forest cover was largely limited to sheltered areas of the east coast and the extreme southwest of Western Australia.

During these glacial maxima the climate was also much colder and windier than today. Minimum temperatures in winter in the centre of the continent were as much as 9°C (16°F) lower than they are today. Hydrological evidence for dryness during glacial maxima can also be seen at major lakes in Victoria's Western District, which dried up between around 20,000 and 15,000 years ago and re-filled from around 10,900 years ago.

As one moves into the Holocene, evidence for climate change declines. During the early Holocene, there is evidence from Lake Frome in South Australia and Lake Woods near Tennant Creek that the climate between 8,000 and 9,500 years ago and again from 7,000 to 4,200 years ago it was considerably wetter than over the period of instrumental recording since about 1885. The research that gave these records also suggested that the rainfall flooding Frome was definitely summer-dominant rainfall because of pollen counts from grass species. Other sources suggest the Southern Oscillation may have been weaker during the early Holocene and rainfall over northern Australia less variable as well as higher. The onset of modern conditions with periodic wet season failure is dated ar around 4,000 years before the present.

In southern Victoria, there is evidence for generally wet conditions except for a much drier spell between about 3,000 and 2,100 years before the present, when it is believed Lake Corangamite fell to levels well below those observed between European settlement and the 1990s. After this dry period, Western District lakes returned to their previous levels fairly quickly and by 1800 they were at their highest levels in the forty thousand years of record available.

Elsewhere, data for most of the Holocene are deficient, largely because methods used elsewhere to determine past climates (like tree-ring data) cannot be used in Australia owing to the character of its soils and climate. Recently, however, coral cores have been used to examine rainfall over those areas of Queensland draining to the Great Barrier Reef. The results do not provide conclusive evidence of man-made climate change, but do suggest the following:

1. There has been a marked increase in the frequency of very wet years in Queensland since the end of the Little Ice Age, a theory supported by there being no evidence for any large Lake Eyre filling during the LIA.
2. The dry era of the 1920s and 1930s may well have been the driest period in Australia over the past four centuries.

A similar study, not yet published, is planned for coral reefs in Western Australia.

There exist records of floods in a number of rivers, such as the Hawkesbury, from the time of first settlement. These suggest that, for the period beginning with the first European settlement, the first thirty-five years or so were wet and were followed by a much drier period up to the middle 1860s, when usable instrumental records start.

Instrumental climate records

Development of an instrumental network

Although rain gauges were installed privately by some of the earliest settlers, the first instrumental climate records in Australia were not compiled until 1840 at Port Macquarie. Rain gauges were gradually installed at other major centres across the continent, with the present gauges in Melbourne and Sydney dating from 1858 and 1859 respectively.

In EAST Australia, where the continent's first large-scale agriculture began, a large number of rain gauges were installed during the 1860s and by 1875 a comprehensive network had been developed in the "settled" areas of that state. With the spread of the pastoral industry to the north of the continent during this period, rain gauges were established extensively in newly settled areas, reaching Darwin by 1869, Alice Springs by 1874, and the Kimberley, Channel Country and Gulf Savannah by 1880.

By 1885, most of Australia had a network of rainfall reporting stations adequate to give a good picture of climatic variability over the continent. The exceptions were remote areas of western Tasmania, the extreme southwest of Western Australia, Cape York Peninsula, the northern Kimberley and the deserts of northwestern South Australia and southeastern Western Australia. In these areas good-quality climatic data were not available for quite some time after that.

Temperature measurements, although made at major population centres from days of the earliest rain gauges, were generally not established when rain gauges spread to more remote locations during the 1870s and 1880s. Although they gradually caught up in number with rain gauges, many place which have had rainfall data for over 125 years have only a few decades of temperature records.

Climate history based on instrumental records

Australia's instrumental record from 1885 to the present shows the following broad picture:

1. Conditions from 1885 to 1898 were generally fairly wet, though less so that in the period since 1968. The only noticeably dry years in this era were 1888 and 1897. Although some coral core data suggest 1887 and 1890 were, with 1974, the wettest years across the continent since settlement, rainfall data for Alice Springs, then the only major station covering the interior of the Northern Territory and Western Australia, strongly suggest 1887 and 1890 were overall not so wet as 1974 or even 2000. In New South Wales and Queensland, however, the years 1886-1887 and 1889-1894 were indeed exceptionally wet. The heavy rainfall over this period has been linked with a major expansion of the sheep population and February 1893 saw disastrous floods in Brisbane.
2. A drying of the climate took place from 1899 to 1921, though with some interruptions from wet La Niña years, especially between 1915 and early 1918 and in 1920-1921, when the wheat belt of the southern interior was drenched by its heaviest winter rains on record. Two major El Niño events in 1902 and 1905 produced the two driest years across the whole continent, whilst 1919 was similarly dry in the eastern States apart from Gippsland.
3. The period from 1922 to 1938 was exceptionally dry, with only 1930 having Australia-wide rainfall above the long-term mean and the Australia-wide average rainfall for these seventeen years being 15 to 20 percent below that for other periods since 1885. This dry period is attributed in some sources to a weakening of the Southern Oscillation and in others to reduced sea surface temperatures. Temperatures in these three periods were generally cooler than they are currently, with 1925 having the coolest minima of any year since 1910. However, the dry years of the 1920s and 1930s were also often quite warm, with 1928 and 1938 having particularly high maxima.
4. The period from 1939 to 1967 began with an increase in rainfall: 1939, 1941 and 1942 were the first close-together group of relatively wet years since 1921. From 1943 to 1946, generally dry conditions returned, and the two decades from 1947 saw fluctuating rainfall. 1950, 1955 and 1956 were exceptionally wet except 1950 and 1956 over arid and wheatbelt regions of Western Australia. 1950 saw extraordinary rains in central New South Wales and most of Queensland: Dubbo's 1950 rainfall of 1,329mm (52 inches) can be estimated to have a return period of between 350 and 400 years, whilst Lake Eyre filled for the first time in thirty years. In contrast, 1951, 1961 and 1965 were very dry, with complete monsoon failure in 1951/1952 and extreme drought in the interior during 1961 and 1965. Temperatures over this period initially fell to their lowest levels of the twentieth century, with 1949 and 1956 being particularly cool, but then began a rising trend that has continued with few interruptions to the present.
5. Since 1968, Australia's rainfall has been 15 percent higher than between 1885 and 1967. The wettest periods have been from 1973 to 1975 and 1998 to 2001, which comprise seven of the thirteen wettest years over the continent since 1885. Overnight minimum temperatures, especially in winter, have been markedly higher than before the 1960s, with 1973, 1980, 1988, 1991, 1998 and 2005 outstanding in this respect. There has been a marked and beneficial decrease in the frequency of frost across Australia

Local variations

With respect to the patterns noted above, there have been local variations. Because of the general spatial coherence of rainfall over most of Australia, these variations have tended to affect small areas, but because these are generally the most populated parts of the continent, they are still of considerable importance.

• In southwest Western Australia, rainfall during the May to August rainy season has declined by 20 percent since 1968, after being at its highest from 1915 to 1947. Floods that were once common have virtually disappeared. Aided by increased winter temperatures and evaporation, runoff has declined over the past forty years by as much as sixty percent.
• In southern Victoria, rainfall since 1997 has declined by as much as 30 percent, with Melbourne having not once exceeded its 1885 to 1996 average since 1997.
  • In contrast, the 1950s in southern Victoria were consistently wet, with Western District lakes returning during the decade to levels seen before the 1850s and Corangamite almost overflowing, as it is believed to have done during the Little Ice Age.
• The eastern part of Tasmania has also seen a major decline in rainfall since the middle 1970s. In Hobart, the annual rainfall has declined by about one-sixth since that time, and not one of the nineteen wettest years since 1882 has occurred since 1976.
• In Gippsland, the coastal areas of New South Wales, and southern Queensland, the driest period since 1885 was not from 1922 to 1938, but approximately from 1901 to 1910, when the average annual rainfall at Sydney was 20 percent below its long-term mean. There was a slight increase in rainfall from 1916 to 1934 and then a decline to 1901-1910 levels from 1936 to 1948, before a return to the pre-1900 "flood-dominated" climate regime occurred in 1949.
• In northwestern Australia, rainfall was moderate from 1885 to about 1925, then declined from the late 1920s to the late 1960s (with very dry conditions during the 1950s), followed by rapid increases since then. In Darwin, six of the seven wettest wet seasons have occurred since 1995, and the major droughts that once affected the region frequently have virtually disappeared since 1971.

Effects of climate change on Australia

Main article: Effects of global warming on Australia

According to the CSIRO and Garnaut Climate Change Review, climate change is expected to have numerous adverse effects on many species, regions, activities and much infrastructure and areas of the economy and public health in Australia and on balance the Stern Report and Garnaut Review expect these to outweigh the costs of mitigation.

According to the Australian Farm Institute, agricultural output in Australia will double in the 40 years to 2050, with climate change expected to increase rather than hinder productivity.

Areas such as southeast Queensland will receive more rain, and as a result will greatly benefit. Recent research has shown increased carbon dioxide in the atmosphere lifts plant production by up to 30 per cent in a phenomenon known as carbon fertilisation.

Australian attitudes to climate change

Historically, because of the high variability of climate in Australia, there had generally been great reluctance among both scientists and the general public to accept the viewpoint that observed medium- or long-term changes in climate are ever permanent. There used generally exist a belief that if a past period has been dry, then wetter conditions will eventually return - though it is by no means unusual for those who experience wet periods when young to expect such patterns of rainfall to continue.

It is only in the last half decade that scientific bodies such as the CSIRO and Australian Bureau of Meteorology have issued reports stating that the cost of failing to act on the threat of climate change is greater than the costs of rapid mitigation.

A 2002 poll on Australian attitudes to climate change shows that 85% of Australians believed that (recent) climate change is a problem caused by humans.. The same poll shows that 77% of Australians want coal fired power stations phased out by 2020.

The issue of climate change, (together with WorkChoices, the war in Iraq and rising interest rates) is believed to have been a major factor behind John Howard's loss of the 2007 election. This was possibly because people were frustrated at the persistent dryness of the weather since 1997 in Melbourne and Perth and 2001 in Brisbane and severe drought for many years in much of the country. It was probably also a result of increased awareness as a result of publicity of the issue from Al Gore's Inconvenient Truth and the public protests of up to 115,000 people (total) at Walks Against Warming around Australia in each of 2006 and 2007.

Environmental lobby groups, while initially pleased with the the Rudd Government's ratification of the Kyoto protocol, are still extremely critical of the Rudd Government's failure to rebalance government subsidies from coal and other fossil fuels to renewable energy in the May 2008 Budget.

There is an increase in the number of scientists declaring themselves to be climate sceptics, and most farmers were sceptical of the claims surrounding climate change and believed they were instead dealing with climate variability. After the recent dry, he hoped the Australian Farm Institute was right in its predictions southeast Queensland would benefit from more rainfall. the dramatic decreases in polar ice caps, the declaration of polar bears as an endangered species and other effects of global warming on Australia are convincing many more people of the dangers of global warming and resultant sea level rise.

That State and Federal governments have accepted that global warming from greenhouse gas emissions is a reality is shown by the establishment of bodies like the Australian Greenhouse Office [1], the recognition that coal is not a sustainable fuel for power generation without carbon capture and storage (so called "clean coal") and the establishment of feed-in tariffs in Australia and mandatory renewable energy targets.

See also

• Environment of Australia
• Greenhouse Mafia
• Greenhouse Solutions with Sustainable Energy
• Mitigation of global warming in Australia