This document was added or updated on 05/02/2010.

CLIMATE CHANGE

Australia experienced its 14^th warmest year on record in 2008 following its 6^th warmest year on record in 2007 (Endnote 1). The annual average temperature for 2008 was 0.41⁰C above the 1961 to 1990 average. Australia’s annual average (mean) temperatures have increased by approximately 0.9⁰C since 1910 (Endnote 1).

2008 marked Australia’s 7^th consecutive warmer-than-average year. Despite this, Australia’s average temperature in 2008 was slightly lower than mean temperatures over the previous six years.

Above-average global temperatures have also been recorded in recent years. The global mean temperature for 2008 was approximately 0.31ēC above the worldwide average (for 1961 to 1990) (Endnote 1). The last year that recorded a worldwide average temperature below the global average was 1985 (Endnote 1).

Most climate scientists from the Intergovernmental Panel on Climate Change (IPCC) agree that a significant proportion of global temperature increases over the last 50 years have been caused by human-induced greenhouse gas emissions (Endnote 1).

Despite the apparent overall warming trend, Australian annual temperatures are expected to continue to vary from year-to-year (Endnote 1).



The two El Niņo–Southern Oscillation (ENSO) phases are El Niņo and La Niņa. El Niņo refers to a warming of surface water over the central and eastern tropical Pacific Ocean. This sea surface temperature (SST) increase is accompanied by changes in the atmosphere measured by the Southern Oscillation Index.

ENSO cycles affect weather patterns across Australia and much of the Pacific Basin. In Australia, El Niņo is often associated with reduced rainfall (Endnote 2). La Niņa refers to the cooling of the waters that warm up during El Niņo periods, and the associated changes in the Southern Oscillation Index. La Niņa periods are often associated with increased rainfall across Australia (Endnote 3).

Rainfall across Australia in 2008 was 478.1 mm, which was only just above the long-term annual average. Above average rainfall was recorded across the Top End (of the Northern Territory), eastern Queensland, northeast New South Wales and far western areas of Western Australia.

Rainfall was below average in other parts of the country. South-eastern Australia, much of which is incorporated in the Murray-Darling Basin, received below average rainfall for the eighth consecutive year in 2008.



Projections indicate that dry conditions will persist across southern Australia in the coming decades (Endnote 1). Therefore, gaining an understanding of the factors driving the long-term drought is particularly important in the context of Australia’s future climate.


ENDNOTES


1. Bureau of Meteorology, 2009; 2008; 2007, Annual Australian Climate Statement 2008; 2007; 2006, <http://www.bom.gov.au/announcements/media_releases/climate/change/>, last viewed October 2009.
2. Bureau of Meteorology, About El Niņo and La Niņa, <http://www.bom.gov.au/climate/enso/about-el-nino-la-nina.shtml>, last viewed October 2009.
3. Bureau of Meteorology, Climate Glossary - La Niņa, <http://www.bom.gov.au/climate/glossary/lanina.shtml>, last viewed October 2009.

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