Climate change in Australia

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Climate change has become a major issue in Australia due to drastic climate events since the turn of the century that have focused government and public attention.^[1]. Rainfall in Australia has increased over the past century, both nationwide and for all four quadrants of the nation ^[2]. Water sources in the South Eastern areas of Australia have depleted due to increasing population in urban areas (rising demand) coupled with climate change factors such as persistent prolonged drought (diminishing supply). At the same time, Australia continues to have the highest per capita greenhouse gas emissions^[3].

All federal and state governments have explicitly ^{[4] [5] [6] [7] [8] [9] [10] [11]} recognised that climate change is being caused by greenhouse gas emissions, in conformity with the scientific opinion on climate change. Sectors of the population^[who?] 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 groups^[who?] are actively campaigning for coal fired power stations and an increase in both number and output of coal mines. Other sectors of the population^[who?] believe it is still too early to tell whether or not there has actually been human induced climate change and believe the naturally high variability of Australia's climate produces too much uncertainty to warrant panic. After publication of the Garnaut report and the White Paper on the proposed Carbon Pollution Reduction Scheme members of this group are increasingly viewed^[who?] as "Climate change skeptics"^{[citation needed]}.

There is expected to be a net benefit to Australia of stabilising greenhouse gases in the atmosphere at 450ppm CO2 eq ^[12] although the coal industry argue this proposition^{[citation needed]}.

Contents 1 Pre-instrumental climate change 2 Instrumental climate records 2.1 Development of an instrumental network 2.2 Climate history based on instrumental records 2.3 Local variations 3 Effects of climate change on Australia 3.1 Economy 3.2 Water 4 Mitigation 4.1 Emissions trading 5 See also 6 References 7 Further reading 8 External links

Pre-instrumental climate change

Paleoclimatic records indicate that during glacial maxima Australia was extremely arid^[13], 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^[14]. 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 12,000 years ago^[15].

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^[16]. 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^[17] 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^[18], 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^[19]. 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^[20], 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 eastern 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^[21]. 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^[22], 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^[23], 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^[24] 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^[25] 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^[26] and in others to reduced sea surface temperatures^[27]. 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 ^[28] across Australia

Local variations

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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^[29]. 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.^{[citation needed]}
• 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.^{[citation needed]}
  • 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.^{[citation needed]}
• 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.^{[citation needed]}
• 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.^{[citation needed]}
• 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.^{[citation needed]}

Effects of climate change 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. The Stern Report and Garnaut Review on balance expect these to outweigh the costs of mitigation. ^[30]

Sustained climate change could have drastic effects on the ecosystems of Australia. For example, rising ocean temperatures and continual erosion of the coasts from higher water levels will cause further bleaching of the Great Barrier Reef. Beyond that, Australia’s climate will become even harsher, with more powerful tropical cyclones and longer droughts.^[31]

Economy

This section requires expansion.

In 2008 the Treasurer and the Minister for Climate Change and Water released a report that concluded the economy will grow with an emissions trading scheme in place.^[32]

A report released in October 2009 by the Standing Committee on Climate Change, Water, Environment and the Arts, studying the effects of a 1m sea level rise, quite possible within the next 30–60 years, concluded that around 700,000 properties around Australia, including 80,000 buildings, would be inundated, the collective value of these properties is estimated at $150billion.^[33]

Water

In June 2008 it became known that an expert panel had warned of long term, maybe irreversible, severe ecological damage for the whole Murray-Darling basin if it did not receive sufficient water by October of that year.^[34] Water restrictions are currently in place in many regions and cities of Australia in response to chronic shortages resulting from drought.^[35] In 2004 Scientist Tim Flannery predicted that unless it made drastic changes the city of Perth, Western Australia, could become the world’s first ghost metropolis - an abandoned city with no more water to sustain its population.^[36]

Mitigation

This section requires expansion.

Emissions trading

• Prime Ministerial Task Group on Emissions Trading

See also

• Contribution to global warming by Australia
• Adaptation to global warming in Australia
• Climate Institute of Australia
• Climate of Australia
• Drought in Australia
• Environment of Australia
• Greenhouse Solutions with Sustainable Energy
• 2009 United Nations Climate Change Conference
• Carbon Pollution Reduction Scheme
• Matthew England
• David Karoly
• Greenhouse Mafia
• Penny Wong
• Climate Code Red
• Ross Garnaut
• Lavoisier Group

References

Further reading

• Spratt, David; Sutton, Philip (2008), Climate Code Red: The Case for Emergency Action, Australia: Scribe Publications 
• Diesendorf, Mark (2007), Greenhouse Solutions with Sustainable Energy, Australia: UNSW Press, ISBN 9-78086-840-9733 
• Preston, B.L.; Jones, R.N. (Feb 2006), Climate Change Impacts on Australia and the Benefits of Early Action to Reduce Global Greenhouse Gas Emissions, the Australian Business Roundtable on Climate Change, Australia: CSIRO 

Soils and agriculture

• Clarke, A. L. (1986), "Cultivation", Australian Soils: the Human Impact, Brisbane: University of Queensland Press, ISBN 9780702219689 
• Conacher, Arthur; Conacher, Jeannette (1995), Rural Land Degradation in Australia, New York: Oxford University Press, ISBN 9780195534368 
• McLaughlin, M. J.; Fillery, I. R. (1992), "Operation of the phospherous, sulfur and nitrogen cycles", Australia's Renewable Resources: Sustainability and Global Change (Bureau of Rural Resources, Proceedings no. 14), Canberra: Australian Government Publishing Service, ISBN 9780644148207 
• McTainsh, Grant H.; Boughton, Walter C. (1993), Land Degradation Processes in Australia, Melbourne: Longman Cheshire, ISBN 9780582870086 
• Roberts, Brian R. (1995), The Quest for Sustainable Agriculture and Land Use, Sydney: UNSW Press, ISBN 9780868403748 
• Woods, L. E. (1983), Land degradation in Australia, Canberra: Australian Government Publishing Service, ISBN 9780644026154 

External links

• Lean, Geoffrey; Marks, Kathy (2009-02-01). "Parched: Australia faces collapse as climate change kicks in". The Independent. http://www.independent.co.uk/news/world/australasia/parched-australia-faces-collapse-as-climate-change-kicks-in-1522529.html. Retrieved 2009-02-04. 
• "Climate change threatening the Southern Ocean". http://csiro.au/multimedia/Climate-change-threat-to-Southern-Ocean.html.