Wednesday, 30 January 2008

How to Make a Start in Junk Science

Having observed this phenomenon in various fields including the link between tobacco and ill health, the link between HIV and AIDS and the link between CO2 emissions and anthropogenic global warming, I can offer a few general hints on how to start a new junk science campaign:

  1. Think of a really obvious objection to a field of science in which many eminent people have put decades of work.
  2. Write up a blog asserting that you have a new, superior theory – ideally one that causes more harm than good, so as to excite attention
  3. Post articles on blogs about the conventional science, asking stupid questions, implying the regulars are ignoramuses
  4. Write letters to the press accusing the mainstream of "junk science" and suppressing dissent, based on angry responses to your stupid questions (no need to mention that your questions were stupid)
  5. Write more articles on your blog, distorting the answers to your questions, and picking out details of the mainstream science which have had to be corrected as evidence that it's all no good

    • Once you start getting responses on your blog, stoke the fires by posting long, snide responses to everyone who disagrees with you
    • You know you've really made it when you start getting supports posting sincere ripostes to your critics

  6. If all goes well, secure a corporate sponsor who benefits from sowing confusion, and you'll have a lifetime of rewarding work, trashing the work of others, ahead of you

Will this work?

It did every time before.

What area should you try? I suggest setting up a campaign to discredit the science showing that cocaine use is harmful. That one hasn't been tried yet. I bet the mafia has even deeper pockets than big tobacco or big oil. No, wait a minute. They probably benefit from cocaine being illegal.

Sorry, you're on your own.

Good luck.

Sunday, 27 January 2008

The Great Queensland Fluoridation Scare

Queensland state premier Anna Bligh announced late 2007 that Queensland would start fluoridating drinking water (at the time only done in a small fraction of the state). Predictably, anti-fluoride campaigns have sprung up.

Is this another scare along the lines of controlling tobacco or climate change will destroy the economy, or is there something in it?

I picked up a pamphlet with a number of claims, and decided to investigate them systematically. After all, if fluoridation really is bad, we ought to stop it.

I am not a dentist or involved in any way professionally or commercially with water fluoridation or dentistry. I just like to get the science straight on matters of public policy.

Here are the “facts” presented as bullet points, and investigated in like style:

  • In healthy adults 50% of ingested fluoride is retained in the body. In young children 80%. (Eksterand et al. Adv Dent Res 1994b;8:175-80) – so what? These numbers are well known and are used to calculate the level of fluoridation that may be safely introduced.
  • Too much fluoride -> poisoning – juxtaposed with the previous fact, this obvious statement (you can die from drinking too much water) is just a plain and simple scare tactic.
  • Baby formula made up with fluoridated water is no longer considered safe (American Dental Assoc. Nov 2006) – I guess they mean this guidance published in November 2006. Nowhere does the article say they consider fluoride in drinking water in any case “unsafe”. However because of the risk of dental fluorosis (discolouring of teeth, not a dangerous condition) if very young children have too much fluoride, they recommend against mixing powdered formula (in any case not the optimum choice of baby food) with fluoridated water. Read the whole article for context. Another scare tactic.
  • Up to 40% of the community will develop fluorosis at the fluoridation levels planned for QLD (York Review, 2000; Fluoridation of Drinking Water; A Systematic Review of Its Efficacy and Safety) – let's see what the actual review, an examination of published evidence said. At a fluoridation level of 1 part per million (ppm), the incidence of dental fluorosis could be up to 48%; that of aesthetic concern, 12.5%. This is the most negative finding reported. 12.5% with slightly off tooth colouring as a cost for reduced dental caries may be an acceptable price to pay, or not – but if we are debating based on the facts, not scares, we can be rational about this. The most important thing about the York Review is its claim that the research (positive and negative) was not of sufficiently high quality to make strong conclusions.
  • 1% of the population displays sensitivity to fluoride in various ways e.g dermatitis, headaches, nausea and abdominal pain (Journal of Dental Medicine 16: 190-99) – they forgot to mention the year in this reference: 1961. A 1961 paper? Hasn’t the matter been studied since then? It turns out is has. The cited paper is reference [100]* in a 1990 paper, which reports a finding by a study that this and related work suffered methodological flaws (see p 9).
  • Only 1% of fluoridated water is drunk. The rest is used in industry or domestically. Fluoridation is inefficient and costly. (Pine Rivers Shire Council, 2005) – This is a good argument for separating industrial water supply (for example to get rid of the debate about drinking recycling water). But it's a pretty weak argument in this context. If you accept the benefits, the costs are very minor by comparison. You could use the same argument against any costs in purifying the entire water supply to drinking standards.
  • Most countries have rejected water fluoridation while Australia and USA still promote it. European countries that have ceased water fluoridation have no increase in tooth decay – no references, so I'd to look this one up. However they have a table in the pamphlet illustrating relative tooth decay rates in fluoridated and non-fluoridated areas, so let’s get back to that after the bullet points.
  • The Australian Dental Association (ADA) aggressively promotes fluoridation but in 2006 the ADA denied any liability for any harm caused by water fluoridation – no reference, so it's hard to investigate this claim. I’m not a dentist so I’ll leave this one for the ADA to defend.
  • Water fluoridation is mass medication denying FREEDOM OF CHOICE [pamphlet’s capitals] – this is an opinion, not a fact. Everyone’s' entitled to have an opinion of course but let’s not misrepresent an opinion as fact.

The pamphlet includes a table featuring areas with and without fluoridation. The rates of tooth decay in the fluoridated areas are from 0.95 to 1.38. The comparable numbers in non-fluoridated areas range from 0.76 to 1.95. All you can really say comparing two sets of numbers with such a wide range is that there must be factors other than fluoridation confounding the statistics. You need to correct for dental hygiene practices, socio-economic differences, naturally occurring fluoridation, diet and anything else that may influence the state of dental health.

What else do they have? They quote a couple of findings from the US National Research Council's 2006 report (I'm guessing they mean Fluoride in Drinking Water: A Scientific Review of EPA's Standards since they don't give a more specific reference) that ingesting fluoride causes hip fractures through increasing bone brittleness, and disrupts thyroid function. Some context is needed here: this report was motivated by complaints that the US Environment Protection Agency (EPA) had set the safety level for fluoridation at 4ppm, more than 4 times the level proposed for Queensland. The focus in the report was on deciding whether this level was too high, with a secondary focus on investigating whether 2ppm would be a safer limit. The conclusion was that 4ppm was probably too high but the risks at 2ppm needed further investigation. Presenting this data as a case against the level of fluoridation proposed for Queensland is either dishonest or incompetent.

There’s more but when I reach the point where I suspect I am being lied to, I hit the ball to the other court. Federer style.

Finally, for those who want to read further to pick up a balanced perspective, here's a good starting point: Hannu W Hausen. Fluoridation, fractures, and teeth (editorial), BMJ 2000;321:844-845.

* Feltman, R. and Kosel, G., Prenatal and postnatal ingestion of fluorides — fourteen years of investigation — final report, J. Dent. Med., 16, 190, 1961

Thursday, 17 January 2008

Solid State Disks and Apple's MacBook Air

Here is an interesting article on SSD vs. HD pricing: Flash Memory vs. Hard Disk Drives - Which Will Win?

In the 1990s, in my advanced computer architecture course, I demonstrated that the price trend of hard drives was going to intersect the price trend of DRAM at around 2004 to 2005. Of course an solid state disk (SSD) can't be made out of DRAM without a robust power source; FLASH has fixed that problem. Even if FlASH is more expensive per bit than DRAM, taking away the need for power means it's a viable alternative to disk and the crossover point wouldn't have moved that far out. The price trend is approximately the same as that of DRAM.

So why aren't we all using FLASH drives, with disks relegated to museums?

Obviously disk manufacturers also have smart people working for them and didn't want to be put out of business. If (as seems very likely) they also spotted the trend, they had 2 options: get into SSDs early (a few did) or push the improvement rate of HDs to match DRAM -- which happened in the late 1990s.

The other interesting observation in the article is that there is a floor price for hard drives -- there is a bare minimum cost for the mechanism that doesn't reduce if you make them smaller. Their graph illustrating this point is a bit misleading: disks are not a fixed price per unit irrespective of capacity; they were trying to represent the scenario that a 64GB drive was the only one available, which is not fully representative (for clarity, they should have shown the graph to the left of the 64GB point as an extrapolation e.g. by dotting the line). For example, very small drives are more expensive to make, on general principles, than very big ones, priced per bit -- an effect to some extent masked by economies of scale for smaller drives. But anyway, the floor price observation is correct.

Why is this floor size observation useful? Because below that size, FLASH can be cheaper than the smallest disk you can buy. Obviously, it will also be lower capacity, but if that's all you need, why spend more on a bigger, slower technology?

If these trends persist, we may reach a point where FLASH is big enough for most mobile devices (at a price point below the cheapest disk). Currently, the cheapest disk is around $50. a 64GB FLASH drive -- as is an option the MacBook Air -- costs about 20 times that. However, if you are happy to have up to 3GB of FLASH, you come out ahead on cost. This would be enough to make minimal bootable system but once you start adding applications and user data with all the cruft (not to mention useful stuff like large data files) those entail, you can burn through 3GB very fast. (My iMac has 2GB in its /Applications directory tree alone, and 77GB in /Users and it's not as if I am making movies on a regular basis.)

If the current rate of improvement continues, with prices halving roughly every three years, if the minimum disk price doesn't drop, you'd be able to use 6GB of FLASH by the same argument. However, minimum disk prices are dropping, and the minimum space you need is a moving target. The only way you would see a substantial change is if there is a new mindset in systems and application development. Even so, users needing large-scale data (movies, big graphics files, databases) would still need disk storage a long way into the future.

So where does this all take us?

First, trends do not continue indefinitely, as we saw with the change in price trend for disks. A breakthrough in how SSDs are constructed could tilt the balance away from disks.

More likely, though, is the emergence of a new computing platform with a smaller memory footprint, but which can use external storage efficiently. It is this detail that is interesting about the MacBook Air -- it's a gentle step towards distributed storage, if only to dispense with the need for an optical drive. A more exciting idea would be the development of a global secure distributed file store, which takes away the need to store all your files on your own platform.

This already exists in the form of the Google File System (GFS) though unfortunately that is not available for general use, outside of services Google provides. In research projects, the Carnegie Mellon Andrew File System (AFS) and its successor Coda were nice ideas. Although the original AFS and Coda projects don't appear to be going anywhere, versions such as OpenAFS continue to be developed. The Hadoop Distributed Filesystem looks interesting too.

So in the long term, I would expect computing to look a bit more like Google's services. Computation would go wherever it was most efficiently performed, and data would be stored wherever was most convenient and efficient, if necessary fragmented and replicated for greater redundancy and bandwidth. Your own personal device would not contain all your data -- only that which was critical for system performance, and cached copies of data for immediate use.

How big a step is the MacBook air towards this? Pretty tiny, actually, but it got me thinking. Good on Apple.

Friday, 11 January 2008

Are we doomed?

The link between smoking tobacco and cancer was first established in the 1930s, and it took about 60 years for a good fraction of the world to accept the need to limit smoking.

The climate change debate is of similar character – some of the same players are even involved. The tactics, not surprisingly, are similar. Promote the view with a combination of bought off scientists and fake grassroots (astroturf) movements that there is more debate about the science than there really is. Promote the view that there is a mafia who attack anyone who opposes the mainstream scientific position. Argue that the mainstream is "junk science" as opposed to opinions of non-specialists, who do not do any real scientific work, who somehow have it right. Position dissenters from the mainstream as Galileos.

No one would be happier than me if the link between CO2 and climate could be convincingly debunked, because the tobacco example shows just how hard it is to change government policy, not matter how convincing the science, in the face of a determined industry lobby. For this reason, I've been taking a skeptical view of the climate change "skeptics": trying to find evidence that they may just be right. This has been pretty heavy going, because a lot of them are clearly uninformed and a lot of "skeptic" commentary is plain garbage. Some of course is valid. In an area as complex as this, there have to be errors and omissions in the accepted models. A genuine scientific skeptic will of course validly explore these problem areas and either find improvements, or overturn the whole model.

So far, in my reading of this work, I've not managed to find anything better than nitpicks. Some details of the models may not be totally accurate, not that anyone ever claimed they were. All of the models used by climate modelers of any worth are reported as representing a range of values, allowing for uncertainties – as they should.

The thing which troubles me about the self-appointed (being kind and not assuming they are not industry shills) "skeptics" is that they all insist that the range of values in IPCC projections are "alarmist", i.e., that the "skeptical" position is that things are better. I have not seen one person in the group widely touted as representing correction to the "mainstream" arguing that science could be badly wrong in the other direction. There are climate scientists in the "mainstream" who argue that some numbers could be optimistic, e.g., James Hansen at NASA argues that we don't have good data to support the view that sea level rise will be within the relatively benign range the IPCC accepts for 2100 (or more recently, 2099).

A true skeptic has to look at the whole range of possibilities for error in the modeling. So, what evidence is there that the modeling could be radically wrong in the direction of optimism?

A popular "skeptic" argument revolves around looking in the paleoclimactic record for instances of temperature-CO2 coupling, and demonstrating that temperature change leads the trend. This is not particularly useful, because such instances do not mirror the current scenario, where gigatonnes of CO2 are being added to the atmosphere independently of a temperature trigger. It is more useful to look for past events where a massive infusion of greenhouse gases was not triggered directly by a temperature increase, i.e., something bigger than can be explained by reduced solubility of CO2 when the oceans warm up.

The best candidate is the Permian-Triassic extinction event (I cite WikiPedia because it's easy to read and accessible, but I have read relevant literature in academic journals as well to check; I encourage other genuine skeptics to read further). Let's call this one the PTE for brevity. PTE is the biggest extinction event since the fossil record began, and wiped out 90% of all life. it took 3-million years for coal to form in significant quantity, so severe was the die-off. What triggered it? That far in the past, exact mechanisms are hard to pin down, but it is known that massive volcanos, the Siberian Traps, spewed out millions of cubic kilometres of lava. Some of this lava landed in coal beds; much also landed in a shallow sea. Seas contain methane clathrates (also called methane hydrates), methane trapped in water molecules in relatively cold water. If the temperature increases, the methane is released. These two effects combined to have a significant greenhouse effect, and the resulting rapid temperature rises may have made the oceans become anoxic. The dominant life form in the oceans became sulfur-reducing bacteria, which exhale toxic sulfur dioxide, which poisoned life on land. How quick was the die-off? One study [Rampino et al 2000] shows that it could have taken under 8,000 years, but definitely less than 60,000 years, for most animals to die off.

How close is this scenario to what is happening today? The Siberian Traps eruptions occurred over a much longer time period, of the order of hundreds of thousands of years at least. The continental configuration was different – this was the era of the single supercontinent, Pangea, so ocean circulation would have been very different. The presence of a significant polar land mass in the south today means we have a larger buffer against warming (sea ice is much less stable than land ice). On the other hand, the atmospheric CO2 levels were very similar to today's before being elevated over a relatively short period by a factor of 5 to 10.

So on balance, I can't say that what is happening today is cause for much optimism. The fact that we are adding CO2 to the atmosphere so much faster cannot be good for the environment. The worst-case IPCC scenario has CO2 levels rising by a factor of 5 on pre-industrial by 2100, scarily close to what happened at the end of the Permian – but thousands of times faster. Time is of course a critical variable in biosphere adaptation. Evolution does not work on decadal time-scales. If forced change in thousands of years was catastrophic, where are we headed now?

Then there's the Paleocene-Eocene Thermal Maximum (PETM), around 55-million years ago. Methane clathrates have also been implicated in this one, as has a release of between 2000 and 5000 gigatons of carbon into the atmosphere over 10,000 to 20,000 years. There is also the possibility of volcanic events causing the greenhouse gas releases. As with the PTE, the key issue is the rapid deployment of greenhouse gases, followed by global warming, then a large-scale die-off. In the case of PETM, the die-off was more restricted, with some molluscs heavily reduced (over 90%); this was the time when many older mammal forms died off, and precursors to modern life forms appeared. As with PTE, the time-scale was much longer than today's. Since PETM is much more recent, it is an easier target for study, and figures in IPCC reports. What is particularly worrying about PETM is that the rate of warming is outside the range of climate models, suggesting that contrary to the common "skeptic" position that cliamte models are alarmist, the opposite may be true.

In conclusion, from what I've found so far, there is a strong relationship between relatively rapid increases in greenhouse gases, similarly rapid climate change, and mass extinctions.

If anyone can find an example of this scale of increase in greenhouse gases (doubling or more, with a baseline similar to today's levels), over a time period short enough to cause problems with biosphere adaptation, which is not associated with a significant extinction event, let me know.

So, to answer the question in the title: are we doomed? On the evidence I've found so far, yes. Until I turn up something better, it seems we have no option but to fight the fossil fuel industry, futile though that may seem. Meanwhile, this all reminds me of one of my favourite Far Side cartoons: "The Real Reason Dinosaurs Became Extinct". A bunch of dinosaurs are seen smoking. Larson tied the two issues together nicely.

In case you can't find references on the net and have a library:

[Rampino et al 2000] Rampino, M. R., A. Prokoph, and A. Adler, 2000. Tempo of the end-Permian event: high-resolution cyclostratigraphy at the Permian-Triassic boundary. Geology, 28: 643-646.