Annual Climate Summary - 2007

Product Code: IDCKGCAR1.2007

The PDF files (see right column) should give good quality prints, but if you require a bound copy of the summary, please contact (03) 9669 4082 during normal office hours from 9:00am to 5:00pm (EST) Monday to Friday, or send an e-mail to webclim@bom.gov.au.

IN BRIEF

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 sixth 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 one 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 each recorded their warmest year on record.

In sixteen of the past eighteen years, Australia’s annual mean temperature has been higher than normal. 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^th December 2007 that the global mean temperature for 2007 was about 0.41°C above average, making 2007 the globe’s seventh 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 meant that long-term droughts persisted in the far southwest and in the southeast, including the Murray-Darling Basin, all of Victoria and northern Tasmania.

Southeastern Australia has been deprived of the equivalent of an average year’s rainfall over the past eleven years, making the current drought one of Australia’s most severe on record; comparable with the Federation drought in terms of rainfall deficiencies. However, the latest drought is notable for its record high temperatures and record low inflows to water storages. Compared with 2006, 2007 was wetter over most of eastern Australia, with much of the Murray-Darling Basin receiving between 200 and 800 mm more rain. In contrast, far north Queensland was generally drier than the previous year, as was much of the northern NT, together parts of WA (most notably northwestern and inland areas).