Monday, February 19, 2007


The excerpt below is yet more documentation for a continuing rise in CO2. But where is the warming that is supposed to go with that? Earth's average annual temperature has not risen since 1998

Yesterday, scientists produced the first evidence that the rampant growth of emerging economies like China is contributing to global warming.

The Norwegian Polar Institute which monitors the air in the Arctic circle, said that the concentration of carbon dioxide in the atmosphere is at a new record and still rising fast. Airborne concentrations of have now reached 390 parts per million, up from 388 a year ago. Before Europe's industrial revolution in the 18th Century, concentrations are believed to have been largely stable at around 270 ppm for several thousand years.

But most scientists now believe that human activity, and especially the burning of fossil fuels like oil, gas and coal, has released ever more carbon into the atmosphere. Kim Holmen, research director at the institute, said that levels have risen particularly sharply since 2000, and those rises have coincided with the emergence of Asian economies like China and India. "The large increases in release rates are definitely in the Asian economies," Dr Holmen said.



By Ross McKitrick (McKitrick is associate professor of economics at the University of Guelph)

Last Friday, the Intergovernmental Panel on Climate Change, the United Nations group charged with assessing the state of the world's climate, unveiled the summary of its latest report. The IPCC Web site claims an impressive number of participants: 450 lead authors, 800 contributors and 2,500 expert reviewers (of which I was one). But it would be a mistake to assume all these experts endorse everything in summary, including its bottom-line assessment: "Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations."

Many disagree with the conclusion itself or the claimed level of certainty, but the fact is, we were never asked. Most participants worked only on small portions of the report, handed in final materials last summer and never ventured an opinion on claims made in the summary. Nor can readers check how well the summary reflects the underlying science. The report itself will not be distributed until May. Although it was officially "released" on Feb. 2, the IPCC is going over the wording to make sure it is consistent with the summary.

This is a curious and disconcerting aspect of IPCC procedures: it needs a couple of months to revise a detailed report prepared by hundreds of scientists, to ensure it agrees with a brief summary drafted by a few dozen scientists and edited by hundreds of bureaucrats and politicians. To be sure, the IPCC does an impressive job of mobilizing experts to produce a report it hopes will be of service to the world. No one should trivialize this achievement.

But let's not make the error of allowing a glossy summary to trivialize the complexities and uncertainties in climate change. After all, if the issues were so simple, you wouldn't need 3,700 experts to write the report. It is a paradox that some of the strongest claims of unanimity in science are made on a subject involving some of the deepest intellectual disagreements and uncertainties.

For instance, the study of climate begins with the movements of fluids: the oceans and atmosphere. The mathematics describing fluids in motion were derived by Claude-Louis Navier and George Gabriel Stokes more than a century ago, but no one has been able to put the equations in a form that would be useful for predicting many key climatic processes. The Clay Institute of Mathematics in Cambridge, Massachusetts, offers a $1 million prize for anyone who can solve the "Navier-Stokes problem," or even just prove that a solution is possible.

In lieu of a solution, scientists use computer models to approximate how the countless processes affecting the climate might behave over time. The IPCC report explains many important limitations of these models: the summary ignores them.

The report fails to achieve balance in other places. For instance, in its 2001 report, the IPCC effectively denied the view that the Earth's climate had cycled through warming and cooling for 10 centuries prior to today's warming. The famous "hockey stick" graph implied warming began with industrialization. I am skeptical of this claim, based on a lot of research-including some high-level expert reviews last year-that showed the data did not support the IPCC claim.

The 2007 report admits problems in this earlier view, but goes on to claim that climate is likely the warmest in 1300 years-precisely what the data don't support. The IPCC also denies that its estimate of rising temperatures, based on weather data collected in ground-level stations around the world, is affected by warming biases due to land-use change, urbanization and the sudden closure of half the world's monitoring stations in the early 1990s.

I am skeptical of their position, based on work I and others have done showing correlations between these influences and temperature trends. There are other examples. Numerous analyses of solar data suggest the sun's output has intensified since the 17th century, and its indirect effect on cloud formation may further amplify its influence on the climate, implying much of 20th-century climate change is natural.

One recent study, by contrast, suggests almost no solar intensification has occurred since the 17th century. That's the study you will read about most in the IPCC report summary. The IPCC leaders have a point of view. Think of their report as the case for the prosecution. Maybe this time the district attorney is right. Maybe not: that is why we need to hear from the defense as well.



By Arnold Kling

"Let's just say that global warming deniers are now on a par with Holocaust deniers, though one denies the past and the other denies the present and future." -- Ellen Goodman

"Global warming is a false myth and every serious person and scientist says so. It is not fair to refer to the U.N. panel. IPCC is not a scientific institution: it's a political body, a sort of non-government organization of green flavor. It's neither a forum of neutral scientists nor a balanced group of scientists. These people are politicized scientists who arrive there with a one-sided opinion and a one-sided assignment. Also, it's an undignified slapstick that people don't wait for the full report in May 2007 but instead respond, in such a serious way, to the summary for policymakers where all the "but's" are scratched, removed, and replaced by oversimplified theses. This is clearly such an incredible failure of so many people, from journalists to politicians." -- Czech President Vaclav Klaus

Pundits, politicians, and the public have a hard time coming to grips with uncertainty. This makes the atmosphere for debating global warming policy especially foul, because the key issues with global warming are the uncertainties involved. Those who would try to reduce the issue of global warming to a yes-or-no question ("do you believe or do you deny?") are not scientists. Real scientists understand uncertainty. Real science deals with uncertainty through relentless, skeptical inquiry. Real science resolves arguments not with consensus, but with data.

My understanding of global warming is influenced by my background in applied statistics and economics. There certainly are scientists who have spent more time than I have analyzing the meteorological data. However, before you call me a "hack," make sure that you are capable of understanding, say, Martin Weitzman's critique of the Stern report. [Excerpt immediately following below]

Two facts are known. One is that the level of atmospheric carbon dioxide has been climbing exponentially. In fact, the overall level of human activity, as measured by total Gross Domestic Product, is perhaps 50 times higher than it was one hundred years ago. Another fact is that over the past 30 years, the average global temperature has increased in total by between 0.5 degrees and one degree centigrade. That means that the average annual rate of increase has been less than one-tenth of one degree per year.

The global warming that has taken place so far is minor. The improvement in living standards that has taken place in the past one hundred years is enormous. The global warming issue has nothing to do with the global warming that has taken place to date. It has everything to do with the global warming that will take place in the future.

This is a matter that depends on climate forecasting. The climate forecasting challenge is to predict the rate of change of global temperature, based on the level of atmospheric carbon dioxide. From a purely statistical standpoint, we do not have the data to do this. The current level of atmospheric carbon dioxide is quite high, even relative to a quarter century ago. We probably have not had enough experience to know the rate of change in global temperature that will result from this high level.

The attempts to cope with this ignorance are known as climate models. Given the sheer complexity of global climate, it is impossible to have much confidence in these models. Perhaps they are better than nothing -- that is, better than a simple statistical extrapolation. However, my guess would be otherwise. For a decade, beginning in about 1978, the economics profession witnessed the utter discrediting of a similar exercise in complex modeling -- so-called macroeconometrics.

Macroeconometrics was supposed to enable you to do something like predict nominal GDP (GDP not adjusted for inflation) based on the money supply. Looking at historical data, this almost seems too easy -- the level of GDP and the level of the money supply both rise over time. Economists thought that they might remove this spurious correlation by "de-trending" the data and then looking at the correlation adjusted for this trend. Unfortunately -- and this is what began to hit home in the late 1970's -- "de-trending" did not remove the spurious correlation.

There was a lot of highly technical analysis undertaken, including work by Nobel Laureate Clive Granger. My take-away from this work is that the amount of meaningful information in macroeconomic data is much less than is necessary for macroeconometric models to be successful. Simple statistical extrapolations work just about as well, and often better. Climate data looks to me suspiciously like macroeconomic data. The true information content probably is not sufficient to produce a reliable model for forecasting.

"Just in Case"

If I thought that climate models were highly accurate, then I would be opposed to any major near-term policy to address global warming. The reason is that the climate models predict gradual, modest global warming over the next century. What that means is that, relative to future GDP, the costs are tolerable. As Weitzman points out, the mainstream economic approach to trading off tolerable future costs against current costs would argue against making significant sacrifices today.

However, Weitzman implicitly shares my concern with climate models. Obviously, we have nothing to worry about if the models are too pessimistic. If it turns out that over the next decade global temperatures edge down, or rise more slowly than the models predict, then we will be relieved. The troublesome possibility is that the models are not pessimistic enough. In fact, Weitzman would argue, and I concur, that the case for doing something today about global warming rests on the fear of the scenario of accelerated near-term climate change -- increases in temperature at a rate that is on the high end of the range being forecast by climate models.

The ideal approach would be a "just-in-case" climate-change mitigation plan. If global warming stays at or under current baseline projections, we probably would do best to simply just adapt. However, if global warming accelerates, we would want to take strong steps to counteract it. In that sense, climate engineering, in which we attempt to use technological means to manipulate global temperatures, would be a good fit. If we had such mechanisms, we could use them on an as-needed basis.

Martin Weitzman also discusses the issue of "just-in-case" policies. "...many hard questions need to be asked. What are early-warning signs of impending environmental disasters like melting ice sheets or thermohaline inversions? How much would it cost to put sensors in place that might detect early-warning signals of impending climatic catastrophes? How early might the warning be before the full effects are felt? What could we do as an emergency response if we received such an early-warning signal? Would last-ditch emergency measures help to ward off disaster by reversing the worst consequences of global warming in time?"

Weitzman concedes that the "just-in-case" approach may not be feasible. "It may well turn out that the option value of waiting for better information about catastrophic tail events is negligible (because early detection is impossible, or it is too expensive, or it comes too late, or because nothing practical can be done about undoing greenhouse warming anyway), but these are conclusions we need to reach empirically, rather than postulating them initially."

Stripped of jargon, what Weitzman is saying is that we should try to study whether a just-in-case approach can work, rather than limit ourselves to the choices of either making huge economic sacrifices or running the risk of climate catastrophe. If we lack "just-in-case" mechanisms, then any approach that we take toward climate change risks making significant errors. We might sacrifice a lot of the world's standard of living in order to reduce carbon dioxide emissions, only to discover that it was unnecessary, because global warming was not going to accelerate, regardless.

Conversely, the reductions that we carry out might turn out to be insufficient. If we do opt for sacrifice, then most economists would agree with Weitzman that the best approach would be to tax carbon emissions. "One can only wish that U.S. political leaders might have the insight to understand and the courage to act upon the breathtakingly-simple market-friendly idea that the right carbon tax could do way more to unleash the decentralized power of greedy, self-seeking American inventive genius on the problem of developing economically-feasible non-carbon-intensive alternative technologies than all of the command-and-control schemes and patchwork subsidies making the rounds in Washington these days." It is possible to have a civilized, sensible discussion about the issue of global climate change. However, doing so requires speaking in the language of uncertainty, rather than moral righteousness.



Martin L. Weitzman


The issue of global climate change and what to do about it has put economics to a severe test in which economists have been challenged to think anew about how to model (or at least how to envision) such fundamental concepts as risk, uncertainty, prediction, and discounting. There is nothing like being asked for a specific policy recommendation on a vivid actuality to put a little life into otherwise arcane matters of economic analysis. Beyond the issue of whether it is right or wrong in its conclusions, The Stern Review of the Economics of Climate Change is an opportunity for economists to take stock of what we know about this subject, how we know it, what we don't know, and why we don't know it.

The Stern Review is a full-fledged economic analysis of climate change that was officially commissioned by the British government, and for both economic and political reasons is an unusual, and unusually important, document. Sir Nicholas Stern is a professional economist of high standing and a distinguished public servant. Weighing in at 600+ pages, the Stern Review is comprehensive in its scope and ambitious in its aims. A non-specialist economist wanting to get a feel for the basic issues of global climate change could do much worse than browse through this report, as it summarizes well the essentials.

A detailed Review of the Review is out of place here it would be too long, and besides the Stern Review reads well and is available on line. Instead I concentrate on trying to distil the Review down to its analytical essence as a piece of applied cost-benefit analysis, because it can be a bit difficult to see the forest for the trees.


On the political side of the Stern Review, my most-charitable interpretation of its urgent tone is that the report is an essay in persuasion that is more about gut instincts regarding the horrors of uncertain rare disasters whose probabilities we do not know than it is about economic analysis as that term is conventionally understood.

Although it is difficult enough to analyze people's motives, much less the motives of a 600-page document, I can't help but think after reading it that the strong tone of morality and alarm is mostly reflecting a fear of (in my ponderously esoteric Bayesian jargon) what is potentially out there in the thick left tail of the reduced-form posterior-predictive probability distribution of g under greenhouse warming. I have argued here that this thick left tail of g is an important aspect of the economics of climate change that every analyst - Stern and the critics of Stern - might do well to try to address more directly.

History will judge whether the economic analysis of the Stern Review was more wrong or more right, and, if it was more right, whether as pure economic analysis it was right for the right reasons or it was right for the wrong reasons.



By Philip Stott

I confess I was afflicted by a profound world-weariness following the release yesterday of the latest gloomy machinations from the Intergovernmental Panel on Climate Change (IPCC). The U.N.'s global-warming caravanserai, founded in 1988 by the World Meteorological Organization and the United Nations Environment Program, had this time pitched camp in Paris, in order to issue the "Summary for Policy Makers" relating to Working Group One of its "Fourth Assessment Report: Climate Change 2007."

This is the group that focuses on "The Physical Science Basis" of climate change, and its summary was greeted with the usual razzmatazz, the Eiffel Tower's 20,000 flashing bulbs being symbolically blacked out on the evening before. Further IPCC reports are due this year, one in April from Working Group Two, on the impacts of, and adaptation to, climate change, and another in May, from Working Group Three on climate-change mitigation.

But it is the science summary that always gives rise to the jamboree -- with journalists, politicians and eager environmentalists desperate to claim that this particular report is the last word on climate change, that it represents a true consensus, that the world is doomed, and that we must recant our fossil-fuel ways. Moreover, as in 2001 with the Third Assessment Report, Friday's release was preceded by speculative leaks, the political shenanigans and spinning beginning even before the final text had been haggled over and agreed upon.

Unfortunately, the IPCC represents science by supercommittee, as rule 10 of its procedures states: "In taking decisions, and approving, adopting and accepting reports, the Panel, its Working Groups and any Task Forces shall use all best endeavors to reach consensus." I bet Galileo would have had a rough time with that.

In this context, it is vital to remember that science progresses by skepticism and by paradigm shifts: A consensus early last century would have given us eugenics. Moreover, the IPCC does no original research, nor does it monitor climate-related data; its evidence is instead from selected secondary sources. But, above all, this supercommittee is more political than is often recognized, rule three firmly reminding delegates that: "documents should involve both peer review by experts and review by governments."

Friday's summary and "best estimates" of temperature-rise by 2100 (as compared to preindustrial times) are thus little more than a committee compromise chewed over by governments with different agendas: an average potential rise of three degrees Celsius (up from 2.5 degrees in 2001); a probable rise of between 1.8 to 4 degrees; a possible rise of between 1.1 to 6.4 degrees. So you can take your pick, also bearing in mind that there are groups outside the IPCC predicting cooling by one or two degrees Celsius.

Moreover, the conclusion that climate changes seen around the world are "very likely" to have a human cause is wonderful Alice-through-the-Looking-Glass talk. Unsurprisingly, the report will please neither a Humeian skeptic nor a rabid apocalyptic. Indeed, even before it appeared, environmentalists were incensed that predictions for the rise in sea levels this century have been lowered to between 28 and 43 cm (11 to 17 inches). They want the polar bears to be drowning now!



Many people would like to be kind to others so Leftists exploit that with their nonsense about equality. Most people want a clean, green environment so Greenies exploit that by inventing all sorts of far-fetched threats to the environment. But for both, the real motive is generally to promote themselves as wiser and better than everyone else, truth regardless.

Global warming has taken the place of Communism as an absurdity that "liberals" will defend to the death regardless of the evidence showing its folly. Evidence never has mattered to real Leftists

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