Is it possible for the sea to rise by 100 metres this century? I was asked that odd question by Andrew Bolt, who is well known for writing incendiary columns refuting climate change in Melbourne's Herald Sun newspaper.
The question was odd for two reasons: first, I am not an authority on climate and do no research as a scientist; second, I was supposed to be interviewing Bolt, not the other way around.
My reason for inviting him to the studio to appear on my ABC Radio program, The Science Show, was straightforward: I had recently been to the renowned Scripps Institution of Oceanography, in La Jolla, California; it was here that atmospheric carbon dioxide had first been monitored 50 years ago. I was at the institute to talk to ice core scientist Jeff Severinghaus about his work.
Severinghaus is a tall, friendly man whose analysis of gases over geologic time scales has shown that temperatures go up as CO2 increases.
He had also observed that the beginning of historic warming periods are not immediately preceded by such a rise in gas. As a result, both Andrew Bolt and other critics of anthropogenic warming (not least the notorious film The Great Global Warming Swindle, aired on ABC TV in July 2007) had proclaimed loudly that our present warming need have nothing to do with greenhouse gases made by humans.
Jeff Severinghaus told me this was totally inaccurate and his work was being distorted, wilfully or not. I duly brought back his interview to be broadcast on ABC Radio and, silly fellow that I am, thought Bolt might appreciate being given a right of reply.
So there I was, facing the notorious newspaper columnist, expecting a swift exchange along the lines of what I've done thousands of times before — on matters of fact.
Instead, what happened next was that each answer contained a gratuitous smear of climate scientists of the likes of Tim Flannery of Sydney's Macquarie University, who'd expressed global concerns about humanity's prospects in the face of climate change. Then, unexpectedly, I was asked whether it was possible that sea levels could rise by 100 metres this century.
I had talked to scientists whose peer-reviewed evidence indicated that mammoth rises were possible under extreme circumstances. As it happened, in Arizona, I'd met leading geoscientist Jonathan Overpeck.
Overpeck's published results last year had gone around the world warning that rises had been grossly underestimated, not least by the highly cautious Intergovernmental Panel on Climate Change (IPCC), which projected a mere 52 centimetre rise.
Overpeck had told me that, historically, the rises had been 120 metres down and 100 metres up from present levels. This was very unlikely to happen soon, but, should temperature increases exceed 3-6°C, "all bets are off".
So my answer was, "Yes, but…"
What happened next was instructive, and demonstrates how the 'debate' is being shanghaied and manipulated according to various agendas. Immediately my words were ridiculed as unrealistic and sprayed around the country from column to blog and on airways far and wide.
It resembled the byplay of campaigning during an election – for that, in the eyes of the warming deniers, is what it is.
Instead of fruitless debates about hypothetical maximum flooding, what we really need to know is whether the sea could rise in a way that would cause catastrophic damage to people and wildlife, regardless of exactly how many metres are involved.
And the answer to that question is a resounding "Yes!".
Many papers have been published (the latest in the U.S. journal Science) warning that sea level rise has been severely underestimated. The evidence has become overwhelming.
So, what to make of this encounter? I draw two conclusions. The first is that the handful of 'climate sceptics' are politically driven and exploit the same trademark clutch of factoids and phrases. They ignore published, peer-reviewed scientific papers containing evidence that shatters their case, vanishingly small as it is.
The noise they make is out of all proportion to their puny numbers, and they protest furiously that all they are doing is trying to save us from unnecessary paralysing angst – rather than inconvenient truth.
The other characteristic of these people is that they lack nuance. After all, everything in science is debatable. Give me any list of conjectures, from the Big Bang to cancer cures, and most scientists in this age of uncertainty would say they are 60 or 70 per cent for or against whatever proposition is served up to them. But 100 per cent?!
The opening lines of the The Great Global Warming Swindle say it all. A hectoring voice-over tells you that those climate scientists have been telling us "lies".
All those CSIRO and NASA physicists, all those academies, all those head scientists from Robert May, former president of the Britain's Royal Society to Jim Peacock, Australia's chief scientist, and all those boffins in industry such as Ronald Oxburgh, former chairman of Royal Dutch Shell petroleum – all coordinated in a global conspiracy of deceit. Really?
Climate science is like evolutionary theory. Since Darwin we have had geology, genetics, palaeontology, anatomy, molecular biology and taxonomy all come together to the same conclusions in a wonderful focus of observed fact.
Climate is moving along the same path, combining maths, physics, natural history, oceanography, geophysics and chemistry. There is always doubt. But let it be constructive.
Robyn Williams has been the host of The Science Show on ABC Radio National since its inception in 1975. A Fellow of the Australian Academy of Science, he is also a member of the Cosmos Editorial Advisory Board.
