Category: Science
New discoveries, the scientific method, and all matters relating to the scientific study of the physical world
How risky is climate change?
On his blog, Lee Jones posted a link to this book review. Basically, the argument is that people are (a) exaggerating the dangers of climate change and (b) using climate change as an excuse to pursue other ends. I would not deny either claim. The Intuitor review of The Day After Tomorrow is evidence of the first, and more can be found in many places. Of course, their review of An Inconvenient Truth suggests that not everyone is guilty of misrepresentation. As for smuggling your own agenda into discussions about climate change, I suspect that is equally inevitable. The question of how to behave justly in response to climate change is fundamentally connected to the history of economic development.
In an unprecedented move, I feel compelled to quote my own thesis:
While the IPCC has generated some highly educated guesses, the ultimate scale of the climate change problem remains unknown. On account of the singular nature of the earth, it is also somewhat unknowable. Even with improvements to science, the full character of alternative historical progressions remains outside the possible boundaries of knowledge. As such, in a century or so humanity will find itself in one of the following situations:
- Knowing that climate change was a severe problem, about which we have done too little
- Believing that climate change was a potentially severe problem, about which we seem to have done enough
- Believing that climate change was a fairly modest problem, to which we probably responded overly aggressively
- Observing that, having done very little about climate change, we have nonetheless suffered no serious consequences.
Without assigning probabilities to these outcomes, we can nonetheless rank them by desirability. A plausible sequence would be 4 (gamble and win), 2 (caution rewarded), and then 1 and 3 (each a variety of gamble and lose). Naturally, given the probable variation in experiences with climate change in different states, differing conclusions may well be reached by different groups.
As such, what it means to make informed choices about climate change has as much to do with our patterns of risk assessment as it does with the quality of our science. Exactly how it will all be hashed out is one of the great contemporary problems of global politics.
Scientific progress goes boink
When I was in the process of applying to Oxford, I filled out a web questionnaire about stress. A few months ago, I was invited to participate in a study and given a two-hour screening. Today, the active part of the experiment began. I know it involves mood and stress, but I don’t have a terribly good idea of what they are looking for.
Today’s poking and prodding
They tested my ability to remember long lists of different kinds of things, particularly after being distracted in various ways. They tested my spatial reasoning in a number of paper and computer based exercises. One annoying one was trying to pick out four different three-digit sequences from a rapid string of numbers, pressing a button when I saw one of them. Because you mind tends to break up the string into a distinct series of three digit numbers, this is extremely hard. 233453456 becomes 233 453 456 starting at wherever you started thinking about it. As such, it is hard to see that 334, for instance, is part of the sequence.
One unusual bit involved playing a betting game on a computer. It showed two bars per screen, yellow in situations where I could win points and blue in those where I could lose them. Some bars were solid and had a single number on them. If you picked them, you were certain to win or lose that amount. Most were split into two fractions, where one was 1/3 of the bar or smaller. Usually, the choice being made was between the certainty of winning or losing a small amount for sure and the possibility of winning or losing more. For example, you might have to choose between a 2/3 chance of losing a small amount and a 1/3 chance of losing a larger amount or a 9/10 chance of losing nothing and a 1/10 chance to losing an even larger amount.
The curious thing is that, as far as my limited arithmetical abilities under such circumstances could be trusted, the bars were always very close to being or exactly statistically equivalent. For instance, you had the option of a guaranteed 66 points or a 1/3 chance at 200 points. As such, as the game went on, I found myself always choosing the ‘safe’ option. This was because I didn’t know the number of trials. You would expect the numbers to be the same for either strategy over the long term. After one million trials, it wouldn’t matter if you had chosen ’33 for sure’ or ‘1/3 of 100’ in every trial, or used any combination of them. If there were a small number of trials, however, choosing the option with more stable returns is less likely to generate an outlying number of points (high or low).
As the game went on, I thought I was doing no better than breaking even. At the end, it said I had over 10,000 points. Of course, it may just have been saying that. You can never be sure what is actually being tested in such experiments. The last, little thing that tends to happen at the end frequently seems to be the most important bit of the whole sequence. Regardless of whether the figure was meant to toy with my emotions or not, I am pretty sure I will get about another £10 at the end of the experiment for it.
In addition to all that, I was asked to tell little stories in response to words, provide definitions to others, and fill out lots of questionnaires about mood and my (non-existent) gambling habits. When called upon to define the words, I felt a bit like Blackadder when he was trying to re-write Samuel Johnson’s dictionary in one night.
The week ahead
For the next week, I need to wear an accelerometer and light meter, as well as keep a diary of eating, sleeping, and exercise. I am meant to wear the measuring equipment as much as possible, though I am not allowed to get it wet or bare-fist box while it is on my wrist. At the end of the week, they are giving me a functional magnetic resonance imaging scan, a diffusion tensor imaging scan, and testing my cortisone levels.
There are 40 other participants, so the total amount of data generated seems very considerable. I hope they find some interesting stuff in there.
PS. Back in March 2006, I hoped the money from this experiment would help me buy a bike. Funny how slowly some things can proceed…
PPS. One of the pictures associated with the Wikipedia article on DTI scans was used in an Economist article this week about synesthesia.
Tragedy of the commons
As a discipline, International Relations is packed with parables. Sometimes, they are hypothetical stories and sometimes they are interpretations of historical events. In each case, they are meant to demonstrate something important about how world politics works. Almost without exception, some aspect of their validity can be questioned on either historical or logical grounds.
When it comes to global environmental politics, perhaps the most well-known such parable is the ‘tragedy of the commons.’ Garrett Hardin is generally credited with coming up with the idea in a paper published in 1968. That said, the same idea was expressed in Michael Graham’s 1948 book The Fish Gate, in which he described how fisheries where access is unlimited will inevitably become unprofitable and fail. The logic of an individual who cannot control the entirety of a resource grabbing as much as possible before its inevitable destruction is the key feature of both analyses.
Personally, I would rather give the credit for the idea to Graham, rather than to Hardin (though it probably far precedes either of them). After all, the latter thinker went on to write such logically and ethically dubious documents as Lifeboat Ethics: the Case Against Helping the Poor. In an illustrative passage, Hardin says:
A wise and competent government saves out of the production of the good years in anticipation of bad years to come. Joseph taught this policy to Pharaoh in Egypt more than 2,000 years ago. Yet the great majority of the governments in the world today do not follow such a policy. They lack either the wisdom or the competence, or both. Should those nations that do manage to put something aside be forced to come to the rescue each time an emergency occurs among the poor nations?
His assertion that affluent societies are such because their leaders have set aside a surplus in times of plenty, whereas the leaders of poor societies have not, represents a massively myopic and superficial understanding of the processes of wealth accumulation, as well as the interactions between historically dominant and historically oppressed states. Explaining patterns of development in such a simplistic way obscures important elements of world economic history. Going on to justify a cold-hearted ethic of indifference to suffering and injustice outside the rich world likewise represents inappropriate extrapolation and faulty thinking.
In a different light
Every once in a while, the Natural History Museum and Pitt Rivers Museum hold an event in the evening. The main area of the Natural History Museum gets nicely illuminated and you get the chance to explore the Pitt Rivers Museum with a torch. That’s the British term for a flashlight, alas. There will be no carrying around pitch-soaked bundles on sticks. That would suit the mood of the Pitt Rivers, but would unacceptably endanger the artifacts. These two museums are certainly the most interesting ones in Oxford, and quite essential for all students to see before they leave.
Even so, such events are well worth attending. Last time, there was an elaborate shadow puppet show. The next one is happening on Saturday May 19th. It runs from 8:00pm to 11:00pm. My account of the previous event can be found here.
Cameron Hepburn on climate economics
Dr. Cameron Hepburn gave an informative presentation in the Merton MCR this evening on the economics of climate change. While it was largely a reflection of the emerging conventional wisdom, it was very professionally done and kept the audience in the packed Merton MCR asking questions right until it became necessary to disband for dinner. Dr. Hepburn, incidentally, is my friend Jennifer Helgeson’s supervisor.
PS. When I imagined Oxford before coming here, the kind of rooms I imagined were more like the Merton MCR than most of the places I have actually seen. That probably derives from having my expectations defined by The Golden Compass and The Line of Beauty.
From Hubble to Webb
NASA has announced some more details on the James Webb telescope, slated to replace Hubble as the most important such instrument in orbit. Hubble is located in an elliptical low Earth orbit, with an orbital height of 589km and an orbital velocity of 7,500 m/s. The Webb will be located at Lagrange Point 2. This is an area where gravity will keep the telescope in a sun-earth line. As a result, the telescope will always be in the shadow of the Earth. NASA has a report on the transition.
Hubble has been one of NASAs great successes over the last 17 years, both in terms of the quality scientific information generated and in terms of the way the project reflects upon the organization. By finally offering an astronomical vantage point not affected by the Earth’s atmosphere, Hubble has been able to make unprecedented observations and discoveries. For example, consider the various exoplanets discovered in recent years, either because of how they obscure stars by passing in front of them or cause stars to wobble with their gravitational pull. Hubble was also ideally placed to observe the impact of Comet Shoemaker-Levy 9 into Jupiter. I remember watching the video feed from that at the Vancouver Planetarium, back in 1994. Some pretty stunning images of the universe have also been generated.
Just yesterday, Hubble may have observed a ring of dark matter. Given the disjoint between how galaxies behave gravitationally and the number and mass of stars we can observe, scientists have speculated that most of the material composition of the universe consists of dark matter and dark energy. The former has gravitational effects but does not interact with electromagnetic radiation. The latter is hypothetically involved in universal expansion: serving as one possible explanation for why the universe is expanding at an expanding rate, as observed through the Doppler shift. Data from the remainder of Hubble’s operational life and the full span of the Webb telescope’s operation may help with the refinement or rejection of both of these ideas, with coincidental improvement in our understanding about the contents and evolution of the universe.
Hubble has been discussed here before. A song about the Doppler shift has also been linked.
Odd bit of pharmacology
I learned an interesting fact at my second Wadham High Table dinner in as many days. Apparently, the antibiotic tetracycline binds aggressively with calcium. This is why you can’t drink milk when you are taking it, since the drug will bond to the milk and not enter your bloodstream. For the same reason, it builds up inside bones and teeth that are growing. If you examine a skeleton from a person who took tetracycline, the bones that were growing at the time can be made to fluoresce.
Because tetracycline turns brown when exposed to light, people who take these drugs while their teeth are still growing are likely to have them turn brown permanently.
The Human Microbiome Project
The average human being is a collection of about ten trillion eukaryotic cells: each with a nucleus, 23 chromosomes of nucleic DNA, and a collection of membrane-bound organelles including mitochondria with genetic material of their own. Less obviously, each person is also carrying around one hundred trillion prokaryotic cells, belonging to thousands of different species of bacteria. The implications of that are pretty staggering. Many of those bacteria play critical roles in biological processes that sustain human life, such as digestion. Others may be the benign residents of niches where more harmful microorganisms might otherwise live.
Following up on the Human Genome Project – which sought to decode the three billion nucleotides in the human genome – the Human Microbiome Project seeks to map the genetic sequences of those legions of bacteria. Already, it has been theorized that these bacteria play important roles in maintaining human health, and that their composition and relationship with human cells has an impact on diseases including diabetes, autism, cancer, and cardiovascular disease. Collectively, these bacterial species are thought to have 100 times more genetic material than the colony of human cells they inhabit.
The project is not unrelated to the Global Ocean Sampling Expedition, discussed here earlier, in that it is delving into the complexities of microscopic ecosystems. In so doing, it might serve both the practical function of helping to better understand and treat human disease and the more esoteric one of refining our understanding of what it means to be a human being, biochemically at least.
PS. The DVDs for the BBC’s Planet Earth series, discussed earlier, are now available in North American format. I will definitely buy a copy when I return to Canada. For those who haven’t seen any of the footage, it is absolutely awe inspiring.
The IPCC and the cost of mitigation
The second half of the IPCC’s Fourth Assessment Report has now been released (PDF). Much like the earlier Stern Review, it was intended to assess possibilities for mitigating climate change and the costs associated with them. As with the Stern Review, the conclusion is that the problem can be dealt with at a fairly modest cost. Certainly, the sums in question are much smaller than the costs that would arise if the worst possible consequences of global warming were realized: from large-scale migration, to problems with C3 crops, to widespread agricultural failures (see this article on the ongoing Australian drought). The Economist is calling it “a bargain.”
That the Stern findings and those of the IPCC broadly agree is not at all surprising. After all, the Stern Review was based almost entirely upon the scientific conclusions of previous IPCC reports. Even so, such agreement can only help to foster increased political consensus, both within and between states, that climate change should be and can be dealt with. More than ever, it seems as though we are witnessing the start of a serious progression towards a low-carbon society.
Dealing the the problem of climate change will require unprecedented foresight and cooperation. As such, it is not unreasonable to think that the emergence of the kind of international regime that would be necessary to address it will foster cooperation in other areas. Something like global fisheries management does not have the same level of importance as addressing climate change, but the tools that will need to be developed to sort out the latter may advance our ability to behave more appropriately in relation to the former.