Australia has sweltered through a record-breaking year of heat, but there’s unlikely to be relief with the Bureau of Meteorology predicting more records to fall.
The Bureau of Meteorology’s annual climate statement shows 2013 was Australia’s hottest year since records began in 1910. The national mean temperature was 1.20 degrees celsius above the 1961-1990 average.
It was significantly hotter than the previous record year, 2005, which was 1.03 degrees hotter than the average.
“Long periods of warmer-than-average days have been common, with a distinct lack of cold weather,” the statement says.
BOM senior climatologist Blair Trewin said 2013 was exceptional as the heat was not associated with a major climate event like El Nino, but it was related to increasing greenhouse gas levels.
“One of the interesting things about this is that outside of 2013 [and 2005] the other four hottest years were all associated with El Nino or close to El Nino conditions in the pacific,” Mr Trewin said.
“Some like 2009 were at the start, others like 1998 were at the end so what makes 2013 exceptional is that we’ve got these very high temperatures without having those warm conditions in the Pacific to drive things.”
Mr Trewin said the hotter temperatures were associated with a number of factors including a long-term warming trend as well as year-to-year variability.
The bureau says Australia has experienced just one cooler-than-average year in the past decade – 2011.
“One of the factors early on was that the summer monsoon was fairly weak and late which meant there was more opportunity for heat to build up in interior Australia than in a normal year.”
In 2013 the nation had its hottest spring, summer, January, September, hottest week, hottest summer day and warmest winter day on record.
Mr Trewin said this record-breaking trend was likely to continue.
“With long term warming trends one of the things you see is an increase in record highs and decrease in record lows, over the last decade record highs have outnumbered record lows by 3 to 1 and we’d expect that ratio to increase further over the coming decades.”
Mr Trewin said the increased levels of greenhouse gases were a major contributor to the long term warming.
“The Australian region warming is very similar to that seen at the global scale, and the past year emphasises that the warming trend continues,” the report said.
“As summarised in the recent Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, recent warming trends have been dominated by the influence of increasing greenhouse gases and the enhanced greenhouse effect.”
The country recorded its hottest day on January 7 – a month which also saw the hottest week and hottest month since records began in 1910.
A new record was set for the number of consecutive days the national average temperature exceeded 39C – seven days between January 2 and 8, 2013, almost doubling the previous record of four consecutive days in 1973.
The highest temperature recorded during 2013 was 49.6C at Moomba in South Australia on January 12, which was the highest temperature in Australia since 1998.
The country also recorded its warmest winter day on record on August 31.
State by state
The year was also the hottest on record for South Australia, Western Australia and the Northern Territory.
In South Australia mean temperatures were 0.41 °C above the previous record set in 2009.
It was the second-hottest year on record for New South Wales and Queensland, third for Victoria and fourth for Tasmania.
Australia and the world
The World Meteorological Organization latest data showed it was likely to be the sixth warmest year on record in 2013.
Based on preliminary data (January–November), the estimated global mean temperature for 2013 is 0.49 °C above the long-term (1961–1990) average of 14.0 °C.
Though Australia had a particularly hot year, Mr Trewin said it was warming in line with the rest of the world.
“In 2012 the US had easily its warmest year on record and Australia had close to normal, in 2013 Australia had its warmest year on record and the US is going to be pretty close to normal.”
No year since 1985 has recorded a below-average global mean temperature and nine of the ten warmest years have occurred in the past 12 years.
The top five hottest years on record
2013 +1.20 °C
This year was characterised by long stretches of warm days. Both maximum and minimum temperatures were well above average; maximum temperatures were 1.45 °C above average, exceeding the previous record set in 2005 by 0.24 °C, while minimum temperatures were 0.94 °C above average, the second-highest on record.
2005 +1.03 °C
The warm conditions in 2005 were remarkably widespread. All States and Territories, apart from Victoria and Tasmania, recorded 2005 mean temperatures amongst their top two warmest years on record at the time. Like 2013, this year’s weather was not influenced by an El Niño weather pattern, making it even more unusual. The BOM report said the record was “yet another sign that our climate is changing”.
1998 +0.85 °C
It took 10 years to break 1988’s hold on the hottest year on record, but BOM said it was unlikely many people would remember 1998 as being particularly warm. Annual mean temperature departures were small because they are averaged over all of Australia, for all of the year. The largest contribution to the record Australian mean temperature came from significantly warmer than usual minimum temperatures throughout the northern half of the continent.
2009 +0.81 °C
This year was characterised by extreme heatwaves across much of southern Australia, with state maximum temperature records in Victoria contributing to the Black Saturday bushfires. An unusual winter-time heatwave occurred during August over large parts of inland Australia and resulted in Australia’s warmest August on record.
1988 +0.69 °C
1988 came at the end of an El Nino weather pattern and the beginning of a La Nina period which saw flooding in New South Wales, Queensland and South Australia during the winter period.
– With AAP