By Phil Shannon
To listen to the Business Council of Australia (BCA), one could be forgiven for thinking that the greenhouse effect is just a load of hot air. At the high profile summit meeting on June 16 between representatives from environmental groups, business and government about reducing Australia's production of greenhouse gases, the BCA was at pains to deny that anything had been proven about greenhouse that would require industry in Australia to modify its carbon-producing ways. Any government regulation would be precipitate and produce economic chaos, according to the peak business group.
On ABC radio's Green and Practical, the BCA representative highlighted the uncertainty of the science of global warming, claiming that no proof had yet been furnished concerning the link between greenhouse gases and climate change. He dismissed as "scaremongering" the citation of major climate events such as floods and droughts as evidence for the greenhouse effect.
In other media appearances surrounding the summit meeting, BCA representatives invoked scientists who are sceptical about greenhouse to argue for a policy of leaving business alone.
The invocation of scientific scepticism by industry bodies like the BCA to argue against a greenhouse gas reduction strategy, besides being clearly motivated by their interest in preserving their profit-making operations, is based on a wrong or mischief-making interpretation of science.
The basic science of atmospheric warming is not in dispute. Trace gases such as CO2, methane, CFCs and nitrous oxides allow solar radiation in the short wavelength spectrum (eg UV rays) to penetrate the atmosphere but prevent some of the re-radiated heat in the long wavelength spectrum (eg infra-red rays) from escaping, thus warming the atmosphere. For naturally produced CO2, methane (and water vapour), this is known as the "natural greenhouse effect".
The same physics apply to the 30% of greenhouse gases which have been generated by human activity since the industrial revolution. This is the "enhanced greenhouse effect". What is uncertain is how significant this human-origin component of global warming is, and by how much and how quickly it will affect the Earth's climate.
To sceptics, it has no significance. All global warming fluctuations are the result of volcanic discharges, sunspot activity, inaccurate measurement etc. In the face of such factors, the projected increase in atmospheric CO2 concentration of around three to six parts per million (ppm) from human-generated activity pales into insignificance.
What this doesn't recognise is the relative effects that different warming mechanisms have. Trace gases are very potent warmers. Small increases in CO2 concentration produce marked and sustained temperature change, and whilst the sceptics are right to argue that factors other than greenhouse gases have been more important in explaining past temperature variation before the industrial revolution in the 19th century, this says little about the future when these other, more potent, factors will kick in at a historically unprecedented rate.
Since the industrial revolution, the amount of carbon in the atmosphere has increased from 580 to 750 billion tonnes and the CO2 concentration from around 270 ppm to 354 ppm (or 420 ppm of CO2-equivalent gases when other greenhouse gases are included). The estimated increase in mean global temperature this century alone has been between 0.3 and 0.7 degrees Celsius. The hypothesis for an enhanced greenhouse effect, based on the accepted cause-effect mechanism of warming due to trace gases, is a sensible one.
Critics, however, claim that the observed level of temperature rise is much lower than that predicted by most greenhouse effect computer models, and that the greenhouse effect hypothesis is therefore invalidated.
But why do the computer models say one thing and the climate data another? There are a number of feedback factors which tend to negate the warming effect of greenhouse gases. Increased cloudiness from a warmer atmosphere is one factor, as is the emission of SO2 (the villain of acid rain) from coal burning: the sulphate particles which form from the oxidation of SO2 in the air, assist the ability of clouds to reflect incoming solar radiation. Nice to know that industrial pollution is good for something!
But not for long. Sulphate pollution only masks the more long-term warming trend; CO2 stays in the atmosphere longer than sulphate particles. There remain good grounds for the consensus that a doubling of CO2 concentrations from pre-industrial revolution levels (which will occur by 2030 if present levels of industrial emissions of greenhouse gases continue, and by 2005-2010 if they increase at their present rate of increase) will cause a 2-4 degree rise in mean global temperature at some stage.
The uncertainty of the degree of warming and when it will happen, and the effects it will cause, are recognised by most scientists, who are also justifiably cautious about claiming the recent disastrous storms in Perth, or floods and droughts worldwide, as conclusive proof for an enhanced greenhouse effect being with us now.
Science can never be certain, as the BCA is quick to point out, concerning global warming science, but there are degrees of uncertainty. It is possible to assess the probabilities and to take action on estimated risks. Unlike the presumption of innocence in law, it is lunatic to assume that greenhouse gases are innocent until proven beyond doubt that they are guilty. The stakes — our sole planetary home — are simply too high.
As the US climate scientist, Stephen Schneider, said on Green and Practical in reply to the sceptics, the choice is between hurting the planet (and ourselves along with it) or hurting the profits of greenhouse industries.
The "hands off industry" call by the BCA of course suits the interests of business, which requires the untrammelled freedom to buy cheap, sell dear and damn the externalities (like the environment and the future of civilisation). This is why it will embrace the arid scepticism of a minority of scientists to provide a scientific gloss to legitimise its unfettered profit-making. So, too, do cigarette companies find the rare study, usually by an industry-employed scientist, which purports to show no link between cigarette smoking and lung cancer.
The greenhouse effect sceptics are asking us to gamble with the planet. But why take the risk? After all, changes which would prevent or moderate global warming, such as preservation of rain forests, development of renewable energy sources, more public transport, are all worth doing with or without the spectre of the greenhouse effect, because there are other environmentally harmful consequences from energy-use patterns and the productive and transportation systems under capitalism.
We (at least those of us who don't own oil wells, coal mines or road freight transport conglomerates) have nothing to lose by taking the greenhouse effect seriously and being wrong about it, but much to lose by ignoring the risks and being wrong. To ignore such odds and do nothing, to dismiss the greenhouse effect, to exploit those genuine areas of uncertainty surrounding greenhouse effect science, as the BCA does, is scientifically unwarranted, socially complacent and politically irresponsible. The ALP government's total disinterest in beefing up its National Greenhouse Response Strategy by enforcing greenhouse gas reduction measures on industry is actively complicit in this.
But that is the way of those who profit from economic activities which damage the environment. There is, indeed, a political battle over the greenhouse effect. On one side is profit, and a science that serves a minority, the money-grubbing capitalists of the BCA. On the other side is everyone else, and a science that should be used to gain an understanding of the planet we live on and how to make it worth living on.