He once flirted with scepticism, but the vocal scientist who this week became a top climate adviser to John Brumby is now one of the world's leading global warming experts.
A LONG time ago, for a brief period in 1987, David Karoly was a climate change sceptic. Like a handful of scientists and a truckload of columnists and MPs today, he doubted that climate change was man-made. Then he looked at the evidence.
"The first paper I ever gave on climate change was trying to disprove that increases in greenhouse gases could be causing these observed trends in temperature," says the Melbourne University federation fellow, who last year shared the Nobel peace prize.
"I was a sceptic — the starting point was that this can't be happening. What we actually found was, the more and more we looked, the more and more agreement there was between greenhouse gas increases and warming in the lower atmosphere and cooling in the stratosphere — which is the pattern under climate change."
It was a revelation that set Karoly on a path to the United Nations Intergovernmental Panel on Climate Change, where he became a lead author. The panel last year shared the peace prize with Al Gore, and Karoly has become one of Australia's most vocal and respected scientists.
As of this week, and despite his damning critique of the Victorian Government's approach to tackling global warming earlier this year, that path also includes heading an expert panel advising Premier John Brumby on climate change policy.
These sort of offers have come with increasing frequency since Karoly — a wiry, gregarious 53-year-old who speaks with the punctuated rhythms of a well-practised storyteller — accepted a lucrative fellowship to return to Melbourne in May 2007. This was after a four-year stint at the University of Oklahoma. But a significant whack of his time has also been spent on a much more mundane task: painstakingly and repeatedly explaining, in his considered yet animated way, the basics of climate change science, occasionally in the media but also for business, schools and community groups.
Why? Because the "very, very robust" science of climate change is frequently and increasingly misrepresented. "I become frustrated because there is no requirement to be truthful in an opinion piece," he says.
"It is amazing to me that, rather than going to CSIRO, the National Academy of Sciences in the US, the Australian Academy of Sciences or other scientific organisations from around the world that are all consistently providing the same evidence, a significant proportion of the (federal) shadow cabinet and many others in the Liberal Party and National Party and other interest groups are collecting information not from reputable sources, but from websites which may or may not be funded by a right-wing lobby group or a fossil fuel company which says there is a conspiracy. But I'm not surprised — people like to hear information that confirms their underlying beliefs."
On the evidence Karoly sees, most doubters have not bothered to read the landmark reports by chief Rudd Government climate adviser Ross Garnaut or the UN climate panel, and those who have dismiss them as political documents. He says both are based on an extraordinary number of individual pieces of research. "If you don't believe them, you really should go read what the original scientific papers say," he says.
For those without the time or inclination to wade through technical papers, Karoly has what is effectively his climate change science for beginners speech, delivered recently as part of the Melbourne University vice-chancellor's research lecture series and in an online post for the ABC.
Roughly summarised, it goes something like this. Over the past 20 years there have been thousands of articles in peer-reviewed scientific journals looking at global warming. For the past decade there has been almost total agreement that the rise in average global surface temperatures since the mid-20th century is mainly due to soaring greenhouse gas emissions caused by human activity. A recent flurry of people on soapboxes challenging this does not reflect a surge of disagreement in the published science — the view of peer-reviewed experts overwhelmingly remains as it has been for years.
The UN panel reports were developed by about 500 scientists, reviewed by another 2000, then sanitised word-by-word at the whim of bureaucrats from about 120 countries until it was a conservative, policy-neutral document with no recommendations. Yet they still came out with the conclusion it was a 90% likelihood humans were causing climate change.
So, what if you're one of those swayed by arguments that the hottest year on record was 1998, and that global average temperatures have dropped in the past six years?
Don't be, says Karoly. Climate change projections factor in large natural year-to-year variations. Warm years such as 1998 were due in part to El Nino events, while the colder temperatures of the past two years have been influenced by a La Nina. Despite this, the planet is about 0.5 degrees hotter than in the middle of last century. Yes, there were periods in the 20th century when temperatures dropped for up to 10 years, but the long-term warming trend never was out of step with climate models.
"Unfortunately, that is not always well understood," he says.
This rise in temperature has coincided with a dramatic surge in burning of fossil fuels, lifting carbon dioxide levels to 30% higher than at any time in the past 500,000 years. More than 20 climate models developed independently by scientists around the globe agree that the temperature rises late last century are only explicable when greenhouse gas increases are factored in.
A future as an environmental policy shaper may have seemed unlikely when Karoly enrolled in a degree in the unfashionable area of applied mathematics at Monash University in the early 1970s. Those who dug deeper, though, would have found a trailblazing pedigree in his family. His father, George, a Hungarian immigrant, helped develop applications for one of Australia's first computers in 1956 and went on to work in Silicon Valley before it was Silicon Valley.
The son took a different path. After a largely theoretical undergraduate degree, he decided to make his study practical and looked at meteorology for the first time during a first-class honours thesis. After finishing, he planned to join the Australian Antarctic Division but was given a last-minute interview for a Shell Australia scholarship to study in England and was selected to go.
The PhD that followed was in a little understood area — the way climate variations in one region, an El Nino in the tropics, for instance, could affect continents at much higher latitudes such as Australia and North America. The common belief was that they couldn't. He found otherwise. As Karoly puts it, the work revolutionised the understanding of large-scale atmospheric dynamics almost by accident — it was only as it finished that he released how groundbreaking it was. More than a quarter of a century on, it has been cited in nearly 1000 separate peer-reviewed journal papers.
After four years at Reading University, Karoly returned to Melbourne in the early 1980s, bringing with him his British girlfriend (and now wife), Susan. He accepted a position as a maths lecturer at Monash University, continuing in different roles for 20 years and eventually running the department. But he also spent long stretches overseas, losing his Australian accent for a mid-Atlantic inflection during a string of visiting appointments at US climate labs. In the process he earned prestigious gongs from the American Meteorological Society and the World Meteorological Organisation. This wealth of experience and respect has brought with it a freedom to speak his mind.
In April, Karoly pointedly questioned the State Government's environmental performance on the eve of it hosting a climate change summit, suggesting that — contrary to Brumby's claim Victoria was leading the way in tackling climate change — it was a leader only in promoting the use of heavy polluting brown coal-fired electricity. Given this, he was surprised to be invited to chair the Premier's climate change reference group that will help guide the development of Government policy.
"I had this dilemma first of all when I was approached — that it's stupid because they are not going to listen and they don't care — but then I thought about it a little more," he says. "It's better to be engaged and try to do it from the inside as part of the process than to snipe from the outside and to be ignored."
It shapes as a challenging relationship. While stressing that these are his personal views, not necessarily those of the group he chairs, Karoly maintains his concerns. If he has his way, for example, Victoria would abandon any thought of new coal-fired power stations until the "clean coal" process of capturing carbon dioxide emissions and burying them underground is shown to be commercially viable.
He sees signs Spring Street is interested, but change is slow. "It is probably becoming more reasonable to say the State Government is no longer burying its head in the sand, but it might just be looking in the other direction when some important decisions need to be made," he says
In the federal sphere, Karoly is underwhelmed by Climate Change Minister Penny Wong's proposed emissions trading scheme, and particularly the Government's plan to compensate coal-fired power stations and offset petrol price rises rather than encourage people to drive less. In Karoly's view, it cannot put Australia on a path to its greenhouse emission cuts by the promised 60% on 2000 levels by 2050 — there are too many compromises.
"I am very, very concerned that it will have negligible impact for the first five to 10 years," he says. While the public debate swirls, Karoly's work rolls on. He has four research fellows developing climate investigations, and is collaborating with other academics. One project that has caught his imagination is a hunt for long-term Australian climate and grape vine data collected through the decades by the country's oldest wineries.
It is this sort of information that Australia lacks. While there is plenty of published research on the local impact of climate shifts in the northern hemisphere, the south has been largely ignored. In Australia's case, Karoly believes this is partly due to it being a young country that, for much of its history, has focused on exploiting its extraordinary natural resources rather than monitoring them.
The dearth of Australian climate data going back more than a couple of decades was highlighted in a recent study Karoly helped lead. Published in Nature in May, the global analysis of about 29,000 long-term sets of data found an overwhelming majority of behavioural shifts observed, whether tree swallows breeding earlier or moths moving north to cooler climes, were statistically unlikely to be caused by anything except a rise in greenhouse gas. Yet nearly all were from the northern hemisphere.
"We were effectively tossing coins and finding nine out of 10 are coming up heads, and that's over 29,000 coin tosses," he says.
"Somewhere along the line we better put money into research looking at what the impacts will be in Australia."
Adam Morton is environment reporter.