Ken Parish supply the expected quibbles for my post on global warming. He illustrates some important statistical fallacies in the process. To support my case that the weather has got no cooler relative to the “the climatic extremes of 1998-2002”, I linked to the NOAA/National Climatic Data Center which showed that during the period since Daly’s post “January-July 2003, the global average land and ocean surface temperature was 0.54¡C (0.97¡F) above the long term mean, third warmest “.

Ken’s response is to go back to the underlying data and perform comparisons between Jan-July 2003 and the corresponding period in 2002, as well as month by month comparisons between 2002 and 2003 . Since the data set consists of deviations from long-term averages, it has no seasonal pattern, and there is, therefore, no justification for this procedure, or for focusing on 2002 when my post referred to the period 1998-2002 (the warmest five-year period on record,). It does, however, mean that the base period for his comparisons includes three of the four warmest months (in deviation terms) in the entire data set, all of which were in early 2002 (you can see them in the graph below). This is a prime example of ‘cherrypicking’.

Ken’s next move is to compare the individual months of June and July 2003 with the corresponding months in 2002, finding them to be cooler by 0.09 and 0.05 degrees respectively, and says “Thus the weather has got cooler since last year, albeit only slightly so far. ” In drawing this conclusion, he ignores the problem of statistical signifiance, which is acute when making pairwise comparisons for periods as a short as a single month. It’s easy to check that, even if you suppose that the data is an average of 1000 independent observations (far too many, given that short-term weather patterns at adjacent points are highly correlated) and that the standard deviation of monthly average temperatures at a given point is 1 degree, the difference found by Ken is statistically, as well as climatically insignificant.

All this might lead you to conclude that you can prove anything with statistics. But in fact, this is one case where you don’t need elaborate statistical analysis. The graph below (taken from NOAA) makes it clear that there is a warming trend that swamps the short-run cycles associated with sunspots and El Nino events.

To end on a positive note, I broadly agree with Ken’s assessment that

If the global average temperature falls back to well below the long-term average by 2006 that would suggest Daly may be correct. On the other hand, if it continues to fall but remains above the long-term average, that will clearly demonstrate the imprint of man-made global warming.

To be more specific, I predict that the average global temperature for 2006, as measured by NOAA, will be above the average for 1971-2000 (the baseline in the chart above) and I promise a retraction if this prediction is not correct.

Given that I’ve been posting on both Kyoto and admissions of error I thought it would be interesting to check if any of the leading contrarians on climate change had revised their views in the light of recent evidence. On past form, I wasn’t expecting much.

The leading contrarians and their organizations (SEPP, Marshall Institute, Cato) cut their teeth in the debate over the ozone laye. Most of them are pretty quiet about this issue now. For example, despite extensive searching I couldn’t find a copy of Sallie Baliunas’ widely-cited article Ozone and Global Warming: Are the Problems Real? which is quoted as saying

there is currently no evidence to suggest that man-made chemicals, like CFCs, have significantly eroded the ozone over most of the world…. Rather than supporting federal regulation, scientific evidence leads to the conclusion that regulation is both economically devastating and scientifically irresponsible. Federal regulation…will cost the U.S. economy an estimated $2 trillion in the near term.”

Still, as far as I know, none of them has ever admitted being wrong, and some, like Fred Singer of SEPP are still keeping up the fight.

Anyway, I was particularly interested in Australian contrarian John Daly because, earlier this year, he took the unusual step of making a testable prediction. In this entry he predicted that, with the sunspot cycle turning down and El Nino ending, the climatic extremes of 1998-2002 would be a thing of the past.

Finally, last year in 2002, even before the solar cycle had started its usual decline towards the cooler Solar Minimum, we saw the development of another El Ni–o on top of an already stretched out solar maximum.Ê A Solar Maximum happening concurrently with an El Ni–o, with no cooling volcanic action for the last 10 years, is a potent combination climatically.Ê And the weather has been very active as a direct result of this combination.

But it will pass.Ê These things always do.Ê The solar cycle is now heading down towards its expected solar minimum around 2006, while the current El Ni–o is expected to wane in the next few months, possibly being replaced by its cooling counterpart, La Ni–a.Ê

The greenhouse industry has thrived off Nature’s climatic drama of the last 4 years, using a combination of public hysteria and bent statistics, but the pickings will be leaner in the months and years ahead – until we reach the next El Ni–o or the next solar maximum expected around 2012 (the same year the Kyoto Protocol expires) .

How has this prediction stood up so far? As Daly’s own site shows, the solar cycle has indeed turned down, and the El Nino has passed, (though without a return to La Nina). But, in case you haven’t been reading the news, the weather hasn’t got any cooler..

Of course, Daly will find a way to ignore all this. Rather than engage in fruitless debate, I’ll offer the following prediction. No matter how hot it is in 2006, we won’t see a retraction from Daly.

A few months ago, I linked to a Ken Miles post saying that Ian Castles, former Australian Statistician and prominent critic of the IPCC and Kyoto was a member of the Lavoisier Group. Ken’s post was based on Lavoisier’s Presidential Report, which stated

Two of our members, Bob Foster and Ian Castles, represented the Lavoisier Group at a workshop conducted by the Australian Academy for Technological Sciences and Engineering (AATSE)

.Ian Castles has written to me (and previously to Ken, who has already posted on this) to advise that this claim by the Lavoisier Group is incorrect, and will be corrected in due course. He is not, and has never been a member of the Lavoisier Group. Here’s a letter from Ian’s co-author David Henderson to USA Today on the same topic.

Dear Sir,

In your issue of April 2, your science correspondent, Dan Vergano, in referring to some recent work by Ian Castles and me, makes two statements which give the wrong impression. First, he describes us as being Ê’associated with the Lavoisier Group’ in Australia. It is true that we both know well the founder of the Group, and we agreed to his request to post our work on their website. But neither Castles nor I are members of the Group; no member of it is or has been involved on our work; and what we have written does not purport to be on the Group’s behalf or to represent its views. We are independent persons, holding no official position, and we speak and write for ourselves alone.

It is also not correct to say that what we have written has ‘appeared in The Economist’ : they published an article (18 February) on our work. They too asked permission to post our critique on their website, and in this case also we agreed.

David Henderson
Westminster Business School
London NW1, England.

For anyone who wants to read all the details, I’ve appended the entire exchange of emails, showing how the Lavoisier Group claim came about.

Read More »

This Salon article has a pretty good roundup of the organisations promoting global warming “scepticism”, including funding sources.

For those more interested in the real science on this topic, I’ve run across an excellent hyperlinked resource entitled The Discovery of Global Warming. While the title makes the author’s viewpoint pretty clear, the treatment is admirably balanced. a very short summary

In the summer of 1988, the hottest on record, scientists’ claims that the Earth’s warming was already detectable focused public concern. But the many scientific uncertainties, and the sheer complexity of climate, made for vehement political debate over what actions, if any, governments should take.

Scientists intensified their research, organizing programs on an international scale. The world’s governments created a panel to give the best possible advice, negotiated among thousands of officials and climate experts. Around the end of the century the panel managed to establish a consensus with only a few dissenters. They announced that although the climate system was so complex that complete certainty would never be reached, it was much more likely than not that our civilization faced severe global warming.

I was particularly interested in the treatment of solar variability, a topic that’s been debated at length in the blogosphere.

The crucial para

The import of the claim that solar variations influenced climate was now reversed. Critics had used the claim to attack regulation of greenhouse gases. But if the planet reacted with such extreme sensitivity to almost imperceptible changes in the radiation arriving from the sun, the planet had to be comparably sensitive to greenhouse gas interference with the radiation once it entered the atmosphere.

All the essays are extensively hyperlinked, and the references are both extensive and wide-ranging.

This report in the Guardian cites leading leftwing thinktank the Institute of Public Policy Research as saying that, according to the latest research at the Hadley Centre for Climate Change, the likely change in temperature by 2100 (under business as usual) will be 8 degrees C, as against ‘consensus’ estimates ranging from 1 to 5 degrees C . The argument is apparently based on claims that CO2 stored in the soil will be released with rising temperatures, producing a positive feedback.

I haven’t followed this up, and it seems surprising that such an obvious mechanism should have been overlooked. So I’m not suggesting that this report should be regarded as reliable. Rather, I want to use this report to illustrate a point I’ve made previously.

A lot of critics of Kyoto argue that, since there’s a lot of uncertainty about the estimates produced by the Intergovernmental Panel and Climate Change and similar bodies, we should ‘wait and see’. These critics tend to pounce on any study that produces an estimate lower than the consensus range to bolster their case.

This neglects the fact that uncertainty goes both ways. There’s a nonzero probability that the rate of warming could be lower than the range suggested by the best available estimates, but it’s equally possible that the rate could be higher. The best available estimates suggest we should do something now (Kyoto) and prepare to do a lot more in the future unless we get a favorable surprise.

In the case of global warming uncertainty actually strengthens the case for action because the damage costs are convex. That is, an increase of 4 degrees will do more than twice as much damage than an increase of 2 degrees and an increase of 8 degrees (the IPPR estimate cited above) would be utterly catastrophic. So, the more uncertainty there is, the stronger the case for action.

When there’s a lot of uncertainty, the important thing is not so much immediate action to reduce emissions as the creation of institutions and mechanisms that will allow large reductions to be made in future. With all its imperfections, the Kyoto agreement is the only process that offers any possibility of progress in this respect.

Ken Parish gives a generally approving link to a piece of junk science claiming that bans on DDT inspired by Rachel Carson’s Silent Spring have caused the deaths of millions of third world residents. He also gives a link to a more balanced piece which gives cautious support to limited use of DDT in anti-malaria campaigns in poor countries (the only use that is currently legal, although there is widespread illegal use as an agricultural insecticide). While noting that not all of Carson’s 1962 claims about the dangers of DDT have stood up to subsequent scrutiny, the author dismisses right-wing conspiracy theories like those in the first link, and makes the point that Carson was campaigning against the use of DDT as a broad-spectrum insecticide, not as an anti-malarial. As the author notes

Soaking the biota in DDT like it was bubble bath, standard practice at the time Silent Spring was written, was a bad thing and Carson was right to condemn it.

As this piece makes clear, the main reason for the abandonment of DDT as the core component in anti-malaria campaigns was the growth of resistance, which was of course exacerbated by indiscriminate use. The ban on DDT use in developed countries, to the extent it had any effect, slowed the general rise of resistant species, and therefore increased the effectiveness of DDT in its anti-malarial use.

The main advantage of DDT is that it is cheap and persistent. Persistence is also one of the main disadvantages, along with broad-spectrum effects. For poor countries, and for the specific purpose of anti-malaria campaigns, the benefits arguably outweigh the costs, and this is why DDT continues to be used in these countries.

The question of when the extra cost of alternative pesticides is sufficiently small to justify abandoning DDT, or sufficiently large to justify readopting it in countries that have abandoned it, is an important one that needs careful analysis. The cause of rational debate is not assisted by propaganda pieces like the one Ken cited.

Note This version has been edited in response to points made by Ken in the comments thread.

The need to rescue the Murray-Darling river system has given rise to some fairly outlandish cost estimates, as well as to the usual extremes of overdone pessimism and Panglossian optimism.

I thought of the following as a back-of-the-envelope exercise in cost estimation. Suppose the government bought back 1500GL of water at $40/ML/year, this would be an annual payment of $60 million, which could be financed from a capital sum of $1 billion at 6 per cent interest. I’d guess that increasing natural flows would solve about half the problem, which would imply a total cost of the order of $2 billion. This is incredibly crude, but I’d think the order of magnitude $1 billion – $10 billion is about right, and that we are likely to end up spending something around the low end of this range.

Update: My estimate doesn’t look too bad according to this report

Gary Sauer-Thompson has responded, arguing that the mess we’ve made of the Murray

puts into question the deployment of the modernist conception of the Baconian Enlightenment project by the liberal state to make Australia modern. This use of modernist science (reductionist and elimination of old ideas by new ones) involved an ahistorical, instrumental reason to improve the human condition coupled to an appeal to a tacit notion of progress. It has been thrown into question because its categories got things messed up

The cascade mode of debate in which an initial post attracted comments, followed by responses, to which further responses were then attached, all indented with quotes, made the old USENet nearly unreadable. Blogs have generally avoided this style. The most notable exception, Fisking, seems to have gone out of style with the winding down of polemics about war and terrorism.

But, in a more civilised form, a question and answer cascade might be helpful. so I’m going to try it in response to Gary Sauer-Thompson’s response to my Murray post. I’ve put Gary’s contributions to the discussion in italics, a device not available in USENet days.

Gary says

John says:

I thought of the following as a back-of-the-envelope exercise in cost estimation. Suppose the government bought back 1500GL of water at $40/ML/year, this would be an annual payment of $60 million, which could be financed from a capital sum of $1 billion at 6 per cent interest. I’d guess that increasing natural flows would solve about half the problem, which would imply a total cost of the order of $2 billion. This is incredibly crude, but I’d think the order of magnitude $1 billion – $10 billion is about right, and that we are likely to end up spending something around the low end of this range.”

I have some queries.

First, this seems to imply that governments enter the water market each year and buy the 1500 gigalitres required for enviromental flows. Why that option? Why not reduce the cap by 10-12%. Why not buy back water licences permanently? Why not take farm land out of production–pay the farmers to leave?

I’m not proposing this as the optimal policy, just one that allows for easy cost estimation. Reducing the cap would have much the same effects, but costs would be borne by farmers rather than the community as a whole. One of the aims of my research project is to look at policies that give both a relatively low-cost (efficient) solution and an equitable sharing of costs and benefits.

Secondly, we have $1 billion for environmental flows and $1billion for the other half of the problem. What is the other half of the problem? Land restoration? Reducing water consumption? Shifting to sustainable agriculture?

Some combination of land restoration and more sustainable agriculture. Again, at this stage I’m just trying to estimate costs, not laying out concrete proposals

Thirdly, how do we go from $2 billion to $10 billion? Is this an insurance for the rapid rise in the cost of water due to increasing shortage?

This just reflects the imprecision of the exercise. I prefer to represent this imprecision in order of magnitude (log scale) terms, rather than as an additive error range.

Fourthly I appreciate its back of envelope calculations but John does talk in terms of “fixing” the Murray. It is not clear what ‘fixing’ means in this context. It is often suggested that the “fixing” problem is about the demand of the domestic consumers, who are unwilling to pay a higher price for their vegetables.

This was implied by Tricky (Ticky, actually) Fullerton in her 4 Corners Sold Down the River. Sure those living in the cities need to change their habits in the use of water, and we need to redesign our cities to make them more sustainable. But the centre of the “fixing “problem is the unsustainable agricultural practices of farming systems (wine industry) geared to exporting their products to an overseas markets.

I’ll look more into this, but I think you’ll find that, given tradable water and a reduction in total allocations, the big reduction in water use will be in irrigated pasture for dairying, which is mostly for domestic markets. Other likely losers of water are rice (mostly domestic) and cotton (mostly export). Horticultural crops like grapes are generally high-value uses of water

.The queries are offered in the spirit of dialogue and debate.

And the responses similarly.

In a piece worthy of Bjorn Lomborg, perennial environmental Pollyanna Alan Moran quotes stats in yesterday’s Fin (subscription required) to prove that everything is roses with the Murray-Darling and that the the sacred property rights of irrigators should not be interfered with. Here’s an extract

Upstream of Morgan in South Australia, salinity levels have been reduced over the past 20 years, and now are at the levels observed in 1938 when salinity was first measured.

Hence, for 1500 kilometres, the river’s agriculture has not adversely affected salinity, which is evident only for the last 200 kms in South Australia.

Similarly, there is no data to support claims that river usage is threatening to eradicate native animals and plants. In fact, the Murray Darling Basin Commission has only recently embarked on a systematic appraisal of the environmental health of the system.

Hence there is little evidence to justify a need for drastically curtailing productive agricultural uses of the river to bolster environmental flows designed, for example, to flush out salt and increase floods of forested areas.

Yet a chorus of voices wants Murray Darling water to be redirected from productive uses to such flows. Simon Crean has endorsed plans to divert 1500 gigalitres, some 20 per cent of the irrigators’ water in the Murray system, to environmental flows.

There are so many distortions here that it’s hard to know where to begin. But the biggest one, and a standard Lomborg tactic, is that Moran tries to argue against environmental policies by pointing to improvements generated by those very policies. As the Murray-Darling Basin Commission points out, significant reductions in salinity have been achieved only since 1990, when a Cap was imposed halting growth in extractions and thereby restricting rights previously exercised or assumed by irrigators (these rights are and were various and complex, and can’t be treated as inalienable private property rights in the simplistic fashion posited by Moran). I’ll be posting more on this in the future as my research gets into higher gear.

Jason Soon links to this piece by Nicholas Thompson making the point the Republicans are losing the support of scientists, essentially because they ignore expert scientific opinion whenever it doesn’t give them the answers they want (Jack Strocchi also alerted me to this). This blog is running a few months ahead of the Zeitgeist on this one. Back in March, I observed

it’s striking that there is now almost no academic discipline whose conclusions can be considered acceptable to orthodox Republicans. The other social sciences (sociology, anthropology, political science) are even more suspect than economics. The natural sciences are all implicated in support for evolution against creationism, and for their conclusions about global warming, CFCs and other environmental threats. Even the physicists have mostly been sceptical about Star Wars and its offspring. And of course the humanities are beyond the pale.

Of course the same is true in Australia, most notably with respect to the global warming ‘sceptics’ (more accurately described as credulous believers in the handful of scientific Pollyannas who tell them wha they want to hear) of the Lavoisier Group. And even creationism is now finding a home among the Quadrant group, though people like McGuinness would no doubt take some sort of Straussian line on this that it’s good for ordinary folk to believe in the literal truth of the Bible, even though sophisticates like Paddy are above such nonsense.