Bureau of Meteorology
Annual Australian Climate Statement 2007
Overview
* Australian annual mean temperature for 2007 was 6th warmest on record (0.67°C above normal).
* Australian annual mean maximum temperature for 2007 was 0.73°C above normal and annual mean minimum temperature 0.61°C
above normal.
* Highest on record annual mean and maximum temperatures across much of the south.
* Warmest year on record for Murray Darling Basin, South Australia, New South Wales and Victoria.
* Australian annual mean rainfall slightly more than average (25 mm above normal).
* Average to above average annual rainfall across northern and central Australia, average to below average annual
rainfall in the southwest, mixed results in the remainder.
* Long-term droughts persist in the far southwest and southeast.
Record warmth across the south
Data collected by the Bureau of Meteorology indicate that Australia's annual mean temperature for 2007 was 0.67°C above
the standard 1961-90 average, making it the nation's 6th warmest year since comparable records began in 1910. Mean
temperatures were above average across Australia during every month except June and December.
Cool temperatures during June were a result of highly unusual heavy rains over northern Australia, and a series of low
pressure systems, including that which caused extensive flooding around Newcastle. Record high temperatures were
observed in the west during February, in the east during May, and across parts of the south during November. Overall,
annual mean temperatures were close to average across the north, while most of the south recorded its warmest year on
record. The Murray Darling Basin, South Australia, New South Wales and Victoria all recorded their warmest years on
record.
(Above) Australian annual mean temperature anomalies (from 1961-90 average) since 1910 and (below) 2007 mean
temperatures compared against historical temperature records.
Australia has now recorded a warmer-than-average year for 16 of the past 18 years. This pattern is not surprising given
that Australia's climate is warming in line with the rest of the globe. The World Meteorological Organization (WMO)
stated on 13 December 2007 that the global mean temperature for 2007 was about 0.41°C above average, making 2007 the
globe's 7th warmest year since records commenced in 1850. There is an overwhelming view from climate scientists
contributing to the assessments of the Intergovernmental Panel on Climate Change (IPCC) that most of the global and
Australian warming over the last 50 years is directly attributable to human emissions of greenhouse gases.
A late-developing La Niña fails to deliver
Based on preliminary data, the Australian mean rainfall total for 2007 was 497 mm, slightly more than the long-term
average of 472 mm. La Niña conditions developed in the tropical Pacific Ocean during 2007. Such conditions are usually,
but not always, associated with above-average rainfall across much of Australia. However, the 2007 La Niña event was
slow to develop and its influence during winter and spring was confounded by a counter influence from the Indian Ocean.
Despite some promising rains during the first half of the year, July to October was particularly dry across the south,
with widespread above-average rainfall not returning until November. Overall, rainfall was average to above average
across northern and central Australia and average to below average in the southwest, with mixed outcomes in the
southeast. Patchy rainfall across southern Australia means that long-term droughts persist in the far southwest and in
the southeast, including the Murray Darling Basin, all of Victoria and northern Tasmania.
(Above) Australian annual mean rainfall (mm) since 1900 and (below) 2007 rainfall compared against historical rainfall
records.
Southeast Australia has now missed out on the equivalent of an average year's rainfall over the past 11 years, making
the current drought one of Australia's most severe on record - comparable in terms of rainfall deficiencies with the
Federation drought. However, the latest drought is notable for its record high temperatures and record low inflows to
water storages.
Climate change projections show a general drying trend across southern Australia over the decades ahead. However, it
remains unclear how much of the current rainfall decline in the southeast can be attributed to human-induced climate
change.
A century of safeguarding the nation's climate record
Australian mean temperatures are calculated from a nation-wide network of about 100 high-quality, non-urban, observing
stations. Extensive data rehabilitation has been undertaken to ensure that the temperature records from these sites have
not been compromised by changes in site location, urbanisation, exposure or instrumentation over time. Australia's
area-averaged rainfall is calculated from a network of around 5000 rainfall stations, most of which are staffed by
volunteer observers.
Since 1 January 1908, the Bureau of Meteorology has been responsible for collecting, managing and safeguarding
Australia's climate record. The national climate archive allows data recorded today to be placed in historical context
and helps Australians manage the risks associated with both short-term and long-term climate change.
ENDS