Part of the problem is that it is hard to find balance in interpreting and understanding the science, the evidence. But The Economist in a recent "Leaders" article and related "Briefing" article, provides as balanced and useful an understanding and prescription as I've read. They address both the error and the harm of overstating the case beyond the evidence, but also the failed thinking that presumes the research and its interpretation must be complete and without error to justify preventative action. The Economist:
CLIMATE-change legislation, dormant for six months, is showing signs of life again in Washington, DC. This week senators and industrial groups have been discussing a compromise bill to introduce mandatory controls on carbon (see article). Yet although green activists around the world have been waiting for 20 years for American action, nobody is cheering. Even if discussion ever turns into legislation, it will be a pale shadow of what was once hoped for.
The mess at Copenhagen is one reason. So much effort went into the event, with so little result. The recession is another...The bilious argument over American health care has not helped: this is not a good time for any bill that needs bipartisan support. Even the northern hemisphere's cold winter has hurt... But climate science is also responsible. A series of controversies over the past year have provided heavy ammunition to those who doubt the seriousness of the problem.
Three questions arise from this. How bad is the science? Should policy be changed? And what can be done to ensure such confusion does not happen again? Behind all three lies a common story. The problem lies not with the science itself, but with the way the science has been used by politicians to imply certainty when, as often with science, no certainty exists.
--"Spin, science and climate change," Leaders Section, The Economist (3.18.10)
Now, that is a provocative opening, one that should warm the hearts of naysayers, those who doubt or disparage the science, those who would let nature and man's influence on it just take its own course. But it is just setting the necessary backdrop, making the appropriate concessions, in setting a fair and useful basis to continue the discussion. The same article continues:
When governments started thinking seriously about climate change they took the sensible step of establishing, in 1989, the Intergovernmental Panel on Climate Change. It was designed to get scientists to work out what was happening to the climate, and to get governments to sign off on the scientists' conclusions. It has done the job of basic science pretty well. There have been occasional complaints both that it has overstated the extent of the problem, and that it has understated it. Its reports trawl through all recent climate science. The wide range of the outcomes it predicts—from a mildly warming global temperature increase of 1.1°C by the end of the century to a hellish 6.4°C—illustrate the uncertainties it is dealing with.
But the ambiguities of science sit uncomfortably with the demands of politics. Politicians, and the voters who elect them, are more comfortable with certainty. So "six months to save the planet" is more likely to garner support than "there is a high probability—though not by any means a certainty—that serious climate change could damage the biosphere, depending on levels of economic growth, population growth and innovation." Politics, like journalism, tends to simplify and exaggerate...
Around the same time it emerged that the most recent IPCC report had claimed that the Himalayan glaciers were going to disappear by 2035, instead of 2350. The panel's initial unwillingness to address this mistake, and the discovery of further problems with its work, raised troubling questions about its procedures.
How bad is this? Sceptics point out that each mistake has tended to exaggerate the extent of climate change. The notion that the scientific establishment has suppressed evidence to the contrary has provided plenty of non-expert politicians with an excuse not to spend money reducing carbon. So the scientists' shameful mistakes have certainly changed perceptions. They have not, however, changed the science itself.
As our briefing explains in detail, most research supports the idea that warming is man-made. Sources of doubt that have seemed plausible in the past, such as a mismatch between temperatures measured by satellites and temperatures measured at the surface, and doubts about the additional warming that can be put down to water vapour, have been in large part resolved, though more work is needed. If records of temperature across the past 1,000 years are not reliable, it matters little to the overall story. If there are problems with the warming as measured by weather stations on land, there are also more reliable data from ships and satellites.
So, is it wise to champion inaction until all doubts and objections by all parties are satisfied? Do we not understand that it is so often the nature of scientific research and prescriptions that they must incorporate uncertainties and the statistical probability of their occurence and impact? It is based on data and probabilities like these that intelligent, wise public policy is often shaped and carried out. And we have been well served by understanding the strengths and limitations of that process. More from the article:
The longer, more detailed "Briefing" in the same edition of the Economist does in fact provided a very useful review of the state of some of the questioned data and interpretations of them. I commend it to your reading. But that more thorough treatment also offers broader perspectives that are equally helpful. From the briefing article, "The science of climate change: the clouds of unknowing":Plenty of uncertainty remains; but that argues for, not against, action. If it were known that global warming would be limited to 2°C, the world might decide to live with that. But the range of possible outcomes is huge, with catastrophe one possibility, and the costs of averting climate change are comparatively small. Just as a householder pays a small premium to protect himself against disaster [property damage insurance], the world should do the same.
This newspaper sees no reason to alter its views on that. Where there is plainly an urgent need for change is the way in which governments use science to make their case. The IPCC has suffered from the perception that it is a tool of politicians. The greater the distance that can be created between it and them, the better. And rather than feeding voters infantile advertisements peddling childish certainties, politicians should treat voters like grown-ups. With climate change you do not need to invent things; the truth, even with all those uncertainties and caveats, is scary enough.
In any complex scientific picture of the world there will be gaps, misperceptions and mistakes. Whether your impression is dominated by the whole or the holes will depend on your attitude to the project at hand. You might say that some see a jigsaw where others see a house of cards. Jigsaw types have in mind an overall picture and are open to bits being taken out, moved around or abandoned should they not fit. Those who see houses of cards think that if any piece is removed, the whole lot falls down. When it comes to climate, academic scientists are jigsaw types, dissenters from their view house-of-cards-ists.
The defenders of the consensus tend to stress the general consilience of their efforts—the way that data, theory and modelling back each other up. Doubters see this as a thoroughgoing version of "confirmation bias", the tendency people have to select the evidence that agrees with their original outlook. But although there is undoubtedly some degree of that (the errors in the IPCC, such as they are, all make the problem look worse, not better) there is still genuine power to the way different arguments and datasets in climate science tend to reinforce each other.
The doubters tend to focus on specific bits of empirical evidence, not on the whole picture. This is worthwhile—facts do need to be well grounded—but it can make the doubts seem more fundamental than they are. People often assume that data are simple, graspable and trustworthy, whereas theory is complex, recondite and slippery, and so give the former priority. In the case of climate change, as in much of science, the reverse is at least as fair a picture. Data are vexatious; theory is quite straightforward. Constructing a set of data that tells you about the temperature of the Earth over time is much harder than putting together the basic theoretical story of how the temperature should be changing, given what else is known about the universe in general...
Adding the uncertainties about sensitivity to uncertainties about how much greenhouse gas will be emitted, the IPCC expects the temperature to have increased by 1.1ºC to 6.4ºC over the course of the 21st century. That low figure would sit fairly well with the sort of picture that doubters think science is ignoring or covering up. In this account, the climate has natural fluctuations larger in scale and longer in duration (such as that of the medieval warm period) than climate science normally allows, and the Earth's recent warming is caused mostly by such a fluctuation, the effects of which have been exaggerated by a contaminated surface-temperature record. Greenhouse warming has been comparatively minor, this argument would continue, because the Earth's sensitivity to increased levels of carbon dioxide is lower than that seen in models, which have an inbuilt bias towards high sensitivities. As a result subsequent warming, even if emissions continue full bore, will be muted too.
It seems unlikely that the errors, misprisions and sloppiness in a number of different types of climate science might all favour such a minimised effect. That said, the doubters tend to assume that climate scientists are not acting in good faith, and so are happy to believe exactly that. Climategate [the e-mail disclosures suggesting bias among investigators at the Climatic Research Unit of the University of East Anglia] and the IPCC's problems have reinforced this position.Using the IPCC's assessment of probabilities, the sensitivity to a doubling of carbon dioxide [having an effect] of less than 1.5ºC in such a scenario has perhaps one chance in ten of being correct. But if the IPCC were underestimating things by a factor of five or so, that would still leave only a 50:50 chance of such a desirable outcome. The fact that the uncertainties allow you to construct a relatively benign future does not allow you to ignore [higher probability] futures in which climate change is large, and in some of which it is very dangerous indeed. The doubters are right that uncertainties are rife in climate science. They are wrong when they present that as a reason for inaction.
No comments:
Post a Comment