Time for some realism

Time for some realism

People are very good at making predictions although, alas, rarely ones which are correct. What we do all too rarely is take a step back and look at earlier predictions through the filter of current knowledge. Although situations change continually, there should be some general lessons to learn from the mistakes of the past. Perhaps the most important is the realisation that projections of current trends are almost certainly going to be wrong and that any conclusions we can draw are subject to considerable uncertainty. Recognition that this is true can be a humbling experience, but should help us see our forecasts more as a range of probabilistic scenarios than likely outcomes.
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> Unfortunately, humility is not much in evidence when it comes to climate change. Earlier this week, Lord Stern (of the eponymous report) claimed that the latest IPCC Assessment Report (of which more later) would seriously understate the problem because some risk factors had not been taken into account (Lord Stern: IPCC report will underestimate climate change). He is quoted by the Telegraph as saying that many economic models ‘grossly underestimate the risks’ because they assume climate change will not affect growth.
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> In a story from the Guardian, he attacks sceptics (Leading climate change economist brands sceptics ‘irrational’): “’The science is unequivocal and shows there is serious danger. What is coming from [sceptics] is just noise, and should be treated as noise.’ He said some sceptics were in the pay of hostile industries, with a vested interest in contradicting the science, and were being ‘deliberately naive’ in claiming the world could wait decades to deal with rising emissions. ‘It (the sceptic response) looks very well-organised,’ he said. ‘They are deliberately distorting the way we understand risk.’"
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> Such talk smacks of desperation: if you can’t persuade an audience that your opponent is wrong by rational argument, then question their credibility. Implying that sceptics are part of some shadowy conspiracy and simply motivated by money is insulting, but suggests that the climate change establishment – with much greater resources at its disposal – is rattled.
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> Today’s much-heralded launch of the first part of the Fifth Assessment Report (actually just the Summary for Policymakers of the report from Working Group 1 on climate science) similarly over-eggs the argument. Their key conclusion is that it is now 95% certain that the primary driver of recent climate change is human activity (WG1 Summary for Policymakers). This has increased since the previous report, published in 2007, but the judgement is a subjective one; there is no objective way of deriving such a metric.
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> To quote from the press release accompanying the report (Human influence on climate clear, IPCC report says): “As the ocean warms, and glaciers and ice sheets reduce, global mean sea level will continue to rise, but at a faster rate than we have experienced over the past 40 years,” said Co-Chair Qin Dahe. The report finds with high confidence that ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010. Co-Chair Thomas Stocker concluded: “As a result of our past, present and expected future emissions of CO2, we are committed to climate change, and effects will persist for many centuries even if emissions of CO2 stop.”
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> He also delivered this key message: "Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system. Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions." And that is the essential argument being made: that carbon dioxide emissions must be drastically reduced to avoid continued unwelcome changes to the climate.
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> Now, this could turn out to be true, but we have to remember that the entire argument has rather shaky foundations. The only facts we have are the evidence of measurements: first that average temperatures have trended upwards since the end of the Little Ice Age (but not smoothly) and second that the levels of carbon dioxide in the atmosphere have risen significantly and are continuing to rise as more coal, gas and oil is burnt. The third fact is that the infra-red absorption properties of CO2 mean that increasing levels will lead to modest temperature rises.
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> That much is clear, but the IPCC reasoning is that this warming is reinforced by positive feedbacks, so raising temperatures considerably more. There is currently no evidence of this so we all, citizens and governments alike, are effectively being asked to trust the IPCC and push ahead with radical and expensive changes to our energy generation and use. Any critical comments which weaken the argument for action are being slapped down. With Canada and now Australia having left the fold of enthusiasts for emissions reduction, the IPCC and its supporters will see AR5 as their last chance to maintain momentum behind their cause.
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> But it looks increasingly likely that they are now swimming against the tide. Their lack of realism about the importance of renewable energy, the failure of Carbon Capture and Storage schemes to be brought on stream and the undeniable fact that CO2 emissions will continue to rise until China’s growth plateaus make current policy look more and more Quixotic (with the difference being they are fighting for windmills, not against them).
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> The IPCC will not get many more chances. If it wants to persuade others of its case, it has to be less dogmatic and more realistic. Arguing that the chances of catastrophe warrant action, even if the scientific evidence is not clear, is a reasonable position. So is the position that emissions reduction should be achieved in the most cost-effective way, without artificial targets for renewables. Favouring nuclear energy would be the obvious long term strategy, delivering an affordable, secure electricity supply even if the enhanced greenhouse hypothesis turns out not to be valid.

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