IT LARGELY went unreported, but January was the hottest on record. Taking a slightly wider lens, the three-month block between November and January also set a new benchmark. The record-breaking heat in the lower troposphere - the part of the atmosphere closest to the earth - came amid news stories of extraordinary snow dumps in parts of the northern hemisphere. The rest of the globe more than compensated.
The latest heatwave follows a 2009 that the World Meteorological Organisation reports was our fifth warmest around the globe and second hottest in Australia. Not long ago these sorts of statistics would have been broadly accepted as part of a wider narrative summed up by the UN's climate panel in 2007: that the evidence the planet is warming is unequivocal and that we can be more than 90 per cent confident that most of the warming is due to human greenhouse gas emissions.
Now, the story told to an only partially engaged public is less clear. Two events have colluded to etch a question mark in some minds as to whether the world faces a potentially catastrophic future.
First, there was ''Climategate'' - thousands of emails leaked from the British University of East Anglia's world-leading Climatic Research Unit that, depending on how you interpreted them, suggested senior scientists had manipulated data and tried to suppress dissenting research.
This was followed by ''Glaciergate'' - discovery of the UN Intergovernmental Panel on Climate Change's howler of a mistake in which it quoted a report by green group WWF that said Himalayan glaciers could disappear by 2035. It prompted an avalanche of other criticisms of the IPCC, many of which have attacked the way it is compiled, rather than punch holes in the science.
''There is a confusion out there,'' says former CSIRO chief of atmospheric research and IPCC author Graeme Pearman. ''Some are suggesting there are manifest flaws in the science and in the IPCC process, which I simply don't accept.''
Many of the criticisms go much further than just suggesting flaws. On the internet, the fight over climate change has become a vicious brawl in which the IPCC panel is dismissed as corrupt, the science of climate change has been proven false and the thousands of scientists who volunteer their time to help write and review the panel's reports are part of a giant scam.
Several climate scientists tell of receiving floods of abusive emails, including death threats, after their names were mentioned on blogs critical of the IPCC. Those who take a public dissenting view, such as Lord Christopher Monckton, have also faced personal attacks that go beyond the strength or failings of their arguments.
Somewhere in all this, the language of scientific debate has been perverted.
"Sceptic" has been misappropriated to mean unswerving non-believer. Non-believers are often tagged as deniers, an ugly term that equates them with those who refuse to accept that 6 million Jews died in the Holocaust.
On the other side, those who put the case that climate change is a man-made problem - the view of an overwhelming majority of the editors of leading scientific journals, the world's scientific academies and governments - are derided as alarmists or, ludicrously, warmists.
How did we get to this point? The body at the centre of these attacks, the IPCC, was not particularly controversial when it was set up by the United Nations Environment Program and the World Meteorological Organisation in 1988 to advise governments on what was then seen as a potential problem. For a long time, the loudest criticisms aired were that it was slow and conservative, lumbering to produce a report every six years that took in the views of about 450 lead authors, more than 800 contributing authors and 2000 reviewers. It went through at least four drafts and received 90,000 comments during a transparent public review process.
The end result of all this was three hefty tomes, each of about 1000 pages, dedicated respectively to the physical science of climate change, its impact on the world and how to respond. The main findings are summarised in a synthesis report ticked off by about 120 governments that uses lay language to inform - or, depending on your point of view, influence - politicians.
Though imperfect, it wasn't until the suggestion that Himalayan glaciers could be gone within 25 years was highlighted last month that the integrity of the panel became a mainstream public issue. Confidence was undermined - if this was wrong, what else might be? The problem was exacerbated when the co-ordinating lead author of the chapter, Indian scientist Dr Murari Lal, was quoted as saying he knew the 2035 date was wrong and chapter had only included it to pressure policymakers. He forcefully denied ever saying this.
The IPCC has acknowledged its mistake and says it regrets it, but has not backed away from the broader claim that glaciers are retreating due to human-induced warming. The report includes several published scientific papers on the subject.
Regardless, the fault prompted a search for other mistakes. To date, the result has been less than compelling. A question to Kevin Rudd on ABC1's Q and A this week picked up on one of the alleged errors - that a suggestion the Amazon rainforest was disappearing had been fabricated. The contentious section is actually not quite as bold: the IPCC said that up to 40 per cent of Amazonian forests could be badly damaged or even lost by even a slight reduction in rainfall. To back this up, it cited a report by environmentalists at WWF. WWF got its own sources wrong, prompting the claims of fabrication. But a 1999 paper published in prestigious journal Nature backed up the claim that ultimately turned up in the IPCC report. Short story: the message in the IPCC report is backed up by published science, even if the way it got in there was flawed.
This, of course, does not mean that the process is good enough. Many of the criticisms of the IPCC have focused on its use of "grey literature" - sources other than peer-reviewed journals and including books and reports by green groups and businesses. They are allowed but, crucially, are not widely used in Working Group One - the most important document that focuses on the scientific case for climate change.
In some cases in working groups two and three, IPCC authors have made the bizarre decision to reference reports by green groups rather than take the extra step and go back to the original source in a published journal. These sorts of oversights, as well as the Himalayan debacle, this week led Working Group One authors to tell The Guardian that their colleagues in Working Group Two had been sloppy - effectively, they had played into the hands of IPCC critics.
The growing criticisms have prompted calls for an overhaul of how climate science is collated and reported.
There are also calls for IPCC chairman Rajendra Pachauri to go, not least because he initially dismissed criticisms of the Himalayan glacier error as "voodoo science", reinforcing perceptions that the panel saw itself as above criticism.
Critics such as William Kininmonth - a former head of Australia's National Climate Centre and prominent dissenter from the IPCC's conclusions - say the international panel should be abandoned. He says its creation was an abrogation by sovereign governments, which should be forming and acting on their own conclusions.
Others prefer a revamp. Former lead author John Christy, from the University of Alabama, suggests the IPCC is dominated by like-minded scientists and marginalises dissenting views. Writing in Nature, he called for the panel to be separated from the UN and the creation of a "Wikipedia-IPCC" that would rapidly assess science, report on new information and better acknowledge uncertainties.
The most frequent change pushed is a division of science and policy. Former IPCC co-ordinating lead author Mike Hulme suggests it should be split into three: a science panel that reports more regularly, a series of bodies looking at local impacts in different areas and a policy group.
Not all are convinced major change is needed. Neville Nicholls, a Monash University climate scientist and IPCC lead author, says imperfections are inevitable in an operation this size, whatever model is adopted. Given the scale of the IPCC report and the recent level of scrutiny he says it is surprising more mistakes have not been found.
''I'd be really shocked in a 3000-page report that has thousands and thousands of references if the only thing you can find is that one [Himalayan] mistake,'' he says.
''This has been out for three years now and they are scouring for problems, and this is the best they can do? It does not undermine the central findings in the summary for policymakers.''
For many scientists, both critics and defenders of the IPCC and the published science behind it, the issue has become one of transparency.
Pearman, who has been involved with the IPCC since its inception, says grey literature should be excluded. While some of it is from reputable sources, such as meteorological organisations, reports from green groups would be out. It is the peer-review process that sets science apart and makes it trustworthy, and this is what must be emphasised so the world's best researchers are not seen as ''just another commentator'', he says.
He also says there needs to be a more widespread acknowledgment that science involves uncertainty. It is a point taken for granted in the scientific community, but little understood beyond it.
Christy said this week: "The truth, and this is frustrating for policymakers, is that scientists' ignorance of the climate system is enormous,'' he wrote. "There is still much messy, contentious, snail-paced and now, hopefully, transparent work to do.''
Pearman does not go this far, but would like to see scientists take a more cautious approach in public statements. ''I think there is uncertainty about the degree of climate sensitivity to greenhouse gas. But that pales in comparison to the risks associated with not acting,'' he says, pointing to the IPCC's projection that 2 degrees' warming - now considered highly likely - would give a 50-50 chance of up to 30 per cent of species becoming extinct. ''That concept of risk management is not well understood and communicating it to the public is not easy,'' Pearman says.
While the debate continues, work on the fifth IPCC assessment report, due in 2014, is under way. Nicholls believes the IPCC is more open than it is credited for, naming scientists with differing views - including John Christy - who have been invited to join and highlighting his own published work on uncertainty over the link between climate change and tropical cyclones. If there were errors in the science, he believes they would have been leapt on by journal editors competing to be at the vanguard of new developments. For years, Nicholls would ''spend the first 20 minutes of every day thinking, 'What's a good experiment to prove the greenhouse effect is wrong', because that would bring fame and riches. Who wouldn't want that? And I couldn't.''
For now, he says: ''My responsibility is to explain the science in as fair and balanced way as I can, with all the caveats and qualifications. And that is where my responsibility ends. I just wish the debate could be more civil.''