Australia's top climate advisory panel has warned strongly against letting the recent mild and wet weather encourage complacency about climate change, insisting the long-term trend remains as alarming as ever.
Following yesterday's CSIRO report that warned greenhouse gas levels were the highest in 800,000 years, the Climate Commission - a scientific agency set up to inform Australians about global warming - expressed concern in a discussion paper that people were confusing weather patterns with long-term climate change.
The climate commissioner and Australian National University academic Will Steffen said 2011 had been dominated by La Nina, the weather effects produced by cool ocean surface temperatures around the equator in the eastern Pacific.
'After a couple of years, the dams are full, everything is green around you, the soil moisture is topped up,'' Professor Steffen said. ''And you say, 'This is looking pretty good. What happened to all the droughts and dry periods that we thought were associated with climate change? That's a very common perception you hear. But these things are superimposed on a longer, underlying trend.''
La Nina produces cooler average temperatures and higher rainfall in Australia, particularly the east. Last year was the warmest La Nina year on record, even though the La Nina effect was particularly strong, the Climate Commission's report states.
Although 2011 was cooler than all but two of the years between 2000 and 2010, it was still warmer than all but one of the years in the 20th century.
''It shows how rapidly things are actually warming,'' Professor Steffen said. ''Last year was something we now consider cool. Yet just a decade ago … this would've been the second warmest year for 100 years.''
The effect of global warming on average rainfall was more difficult to predict, the commission's report stated.
The two years of 2010 and 2011 set a record of 1409 millimetres of rain averaged over the whole country.
Even still, the two-year wet period has made up for only about a third of the rainfall deficit since 1997. ''We still require many years of wetter than average conditions before we can fully eliminate the rainfall deficit of the big dry,'' it states.
The paper came as a separate report from the Climate Institute, an independently funded think tank, argued Australia could get more out of its carbon pricing scheme - including cheaper emissions cuts and greater environmental benefit - by focusing its carbon trading efforts on neighbours such as Indonesia rather than Europe.
The institute's deputy chief executive, Erwin Jackson, said Australia should be using bilateral or regional trade deals as a model to set up carbon trading links with individual countries, especially developing countries in the Asia-Pacific region.
Trading carbon with Indonesia's energy sector, for example, would deliver Australia cheaper carbon abatement because Indonesia could cut its emissions relatively easily. At the same time, Australia would be leveraging more global action compared with linking to Europe, which already has a carbon scheme.
''By providing export opportunities to Indonesia, it would leverage even more significant action than is currently being contemplated while at the same time providing opportunities to Australian businesses to reduce emissions at lower cost.
''The key challenge for Australia is leveraging greater global ambition because we are very vulnerable to the effects of climate change. Just linking with the EU, while important, doesn't deliver that.''