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.We have spent too long being risk-averse about short-term costs and ignored the benefits of avoiding long-term damages.If only the IPCC would adopt such an attitude.Those turning to the 2007 IPCC reports for an up-to-date, authoritative view on global warming will find little of the real discussion of the events in the Arctic with which we started our story.The 2007 report is the IPCC’s strongest call yet for governments, businesses, and communities to act immediately to reduce greenhouse emissions.But it is not enough, because it is based on outdated and incomplete data sets.The IPCC’s four-year schedule for producing reports requires a submission deadline for scientific papers that is often two years, or more, before the report’s final publication.What happens if there is significant new evidence, or dramatic events that change our understanding of the climate system, in the gap between the science reporting deadline and publication? They don’t get a mention, which means that the IPCC report — widely viewed as the climate-change Bible — is behind the times even before it is released, though some new data is presented at forums.On 28 January, just days before the release of the first of the IPCC’s 2007 reports, the science editor of The Observer, Robin McKie, told of a serious disagreement between scientists over the report’s contention that Antarctica will be largely unaffected by rising world temperatures:[M]any researchers believe it does not go far enough.In particular, they say it fails to stress that climate change is already having a severe impact on the continent and will continue to do so for the rest of century.At least a quarter of the sea-ice around Antarctica will disappear in that time, say the critics, though this forecast is not mentioned in the study.One expert denounced the [IPCC] report as ‘misleading’.Another accused the panel of ‘failing to give the right impression’ about the impact that rising levels of carbon dioxide will have on Antarctica.As McKie notes, the IPCC is, necessarily, a careful body.Its reports involve the synthesis of many hundreds of pieces of research, and cooperation between many authors and contributors, such that only points that are considered indisputable by all of them are included: ‘This consensus deflects potential accusations that the body might be exaggerating the threat to the planet.But the critics say it also means its documents tend to err too much on the side of caution.’Under intense pressure from global-warming deniers, the IPCC has adopted some methods that have gone beyond being ‘careful’ and are now simply conservative.Fred Pearce, writing in New Scientist on 10 February 2007, tells of an IPCC review process that was ‘so rigorous that research deemed controversial, not fully quantified or not yet incorporated into climate models was excluded’.Pearce wrote: ‘The benefit — that there is now little room left for sceptics — comes at what many see as a dangerous cost: many legitimate findings have been frozen out.’ After interviewing many of the scientists involved, he described the process as ‘a complex mixture of scientific rigour and political expediency [that] resulted in many of the scientists’ more scary scenarios for climate change — those they constantly discuss among themselves — being left on the cutting room floor’.The peer-review process for experimental science is conservative, insisting on verifiable, reproducible results.Peer-review can significantly delay the full publication of new findings.When research produces a range of outcomes with differing probabilities or risks, there is a tendency for the general reader, and even policy-makers, to be drawn to the middle position — or even to the low end of the range, which requires less action.Wider uncertainties in climate science and the vulnerabilities of species to fast rates of temperature change are good examples, because they drive us to consider the worst outcomes — not just the scenarios that have average effects.Some of the high-impact scenarios considered by the IPCC to be ‘extreme’ are now looking quite likely.Barrie Pittock says that uncertainties in climate-change science are inevitably large, due to inadequate scientific understanding, and to uncertainties in human agency or behaviour.He says:[Policies] must be based on risk management, that is, on consideration of the probability times the magnitude of any deleterious outcomes for different scenarios of human behaviour.A responsible risk-management approach demands that scientists describe and warn about seemingly extreme or alarming possibilities, for any given scenario of human behaviour (such as greenhouse gas emissions), even if they appear to have a small probability of occurring.This, he says, is recognised in military planning, and is commonplace in insurance; the lesson for climate policy is that the object of policy advice must be to avoid unacceptable outcomes, not to determine the most apparent, likely, or familiar outcome [ Pobierz całość w formacie PDF ]