One safe prediction, though, is that climate change will remain a hot political issue. The Abbott government has vowed to scrap the carbon price and replace it with a so-called direct action plan to pay polluters to curb emissions. Whether the program can succeed in cutting Australia's total emissions by 5 per cent on 2000 levels by 2020 remains in doubt as emissions continue to rise, deforestation rates increase and the mining industry prepares for a major expansion of coalmining and liquefied natural gas production. The CSIRO and the Bureau of Meteorology will give science prominence amid the political battle, with the release on March 4 of an updated State of the Climate report. The previous report, released in 2007, said Australia could expect annual warming of one degree by 2030 on 1990 levels. Paul Holper, manager of the Australian Climate Change Science Program, said the March snapshot would include the latest observations on climate and trends.



''With temperature, we've been saying pretty much the same thing for ages,'' Holper said.

''It doesn't require any great scientific insight to know that if you add heat-trapping gases to the atmosphere then the atmosphere is going to trap more heat, and temperatures are going to go up. That's precisely what we've seen.'' To get a sense of how exceptional 2013 was for heat, a little history comes in handy. Weather enthusiasts could pluck out records of note in 2013, such as the warmest day (40.3 degrees, January 7), and the warmest winter day (29.92 degrees, squeaking in on August 31). For all days since 1911, 20 of the nationally averaged warmest days were spread across the 40 years between 1911 and 1950. In 2013 alone there were 23 such days, the Bureau of Meteorology said. But climate experts were just as surprised by the lack of cold weather: no part of Australia reported below-average temperatures. Without the cold spells, warmth building up across Australia's hot heart lasts longer, reaches further.

In 2013, maximums nationally were 1.45 degrees above the 1961-90 average used as the standard yardstick, easily beating the previous record of 1.21 degrees set in 2002. Mean temperatures were also a record, at 1.2 degrees above the norm, well above the previous 2005 high of 1.03 degrees. This week, conditions have again been scorching - in parts of NSW, South Australia and Queensland close to 50 degrees. Walgett, in NSW, hit 49.1 degrees on Friday, the highest for the state since 1939. Overall, though, 2013 may send the loudest alarms because it occurred without a major spur from weather systems such as the El Nino-Southern Oscillation. El Nino years are marked by a shift in wind patterns that typically trigger warmer and drier conditions over Australia, particularly the eastern states. An El Nino year can add as much as 0.5 degrees to average temperatures during summer in Australia, and 0.2-0.3 degrees overall for global temperatures. It's not yet known whether 2014 will be an El Nino year. Scientists say this should become clearer by autumn. ''We get hotter temperatures in an El Nino year because we get lower rainfall,'' said David Karoly, a climate scientist at the University of Melbourne and a member of the Climate Change Authority which advises the federal government on policy. ''The fact we had average rainfall in 2013 and we also got record temperatures is somewhat surprising.''

David Jones, head of climate analysis at the Bureau of Meteorology, said 2013 record temperatures are a clear signal of climate change. ''If you took away the global warming trend, we probably could not have seen a year this high,'' Jones said late last month. Loading Karoly agrees. None of the simulations of nine major models generating 13,000 years of natural variability produced the record temperatures without an increase in greenhouse gases. ''In simulations for the period of 2006 to 2020 with natural variability and human influences, including increases in greenhouse gases, such records occur approximately once in every 10 years,'' Karoly said. ''Hence, this record could not occur due to natural variability alone and is only possible due to the combination of greenhouse climate change and natural variability on Australian average temperatures.''