Poloneck pedagogy
Re Feedback’s selection of items bringing together the disciplines of science and knitting (27 May): I am delighted to hear that there is a pattern for a knitted uterus. I used to lecture my Pregnant Mums classes in a polonecked sweater, as I found it an acceptable illustration of the way the uterine cervix allows the descending baby’s head to pass; as I got older it was necessary to apologise and ask the audience to imagine me upside-down.
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Spain's gain
I would like to express my opinion on Fred Pearce’s article on the permission given to Spain by the European Union to increase its carbon dioxide emissions by 25 per cent during the 1990s (“The Costa del Carbon Dioxide”, 6 May). This is possible due to the agreement between the nations of the EU, in which they resolved to meet the targets agreed in the climate convention jointly instead of individually.
This agreement allows for the possibility of industrial growth in Spain, which might help the country recover from its current economic crisis. (Other sectors of the economy, such as agriculture, are suffering from EU regulations and severe growth restrictions.)
Since present CO2 emissions differ considerably from one country to another (in values per head), if we all decided to reduce our emissions progressively by a certain percentage, that would permit some countries to have larger quotas for CO2 emissions than others. Would that be fair? Why is the author so concerned about Spanish emissions? Even if the 25 per cent increment were possible (which is not likely, considering the recession), Britain’s emissions would still be 50 per cent higher, and those of the US nearly three times as much.
We should all take steps to try to reduce our emissions of greenhouse gases, but those who contribute more should try harder. Nevertheless, I do not think the biggest “CO2 producers” would agree to reduce their emissions drastically, considering the effects that this could have on their economies. Solutions should be adopted in every country, but the peculiarities of each economy must also be taken into account.
Concern for global warming is prevalent in Spanish society, as the Spanish people do not need to wait until ma帽ana to notice the effects of climatic changes; the southern part of the country is suffering hoy from droughts and the risk of desertification has increased in some areas.
The comment at the beginning of the article on the recent conflict between Spain and Canada over fishing stocks was out of context, and the tone in which it was made was something we would expect to find in another type of publication.
Blow it up
“Can Cameroon’s lethal lake be made safe?” asks Tara Patel (This Week, 27 May). Of course: here are some cheap and safe ideas to get Lake Dyos to burp its deadly CO2 to order. The principle is simple enough. If everyone knows exactly when the lake will erupt, everyone can (and surely will) get the hell out of it. All we need is to trigger the release and to do that, the currently metastable system has to be destabilised. This should be very easy, using high explosives in one of the following ways.
Place explosive charges in part of the crater wall to simulate the sort of major landslip which apparently triggered the deadly 1986 gas release. Detonate remotely.
Drop naval depth charges from an aircraft, set to explode close to the lake floor.
Place high explosives with a pressure-activated detonator on a deliberately leaky craft (boat, raft) moored in some way over the deepest part of the lake (having noted how long it would take to sink) and retire.
This is crude empiricism at its best. I would expect the explosives or landslide to upset the lake’s equilibrium, but if everyone has evacuated first, no harm will be done. Obviously the whole event should be monitored remotely to see just what does happen. If it works, all we have to do is to repeat this simple procedure every five years or so, depending on the gas build-up.
Cameroon should be able to afford this too.
Over the moonbow
In the middle of May this year I was fortunate to be part of a happy group of ten people on a beach near Lockhart River, a very remote Aboriginal community near the tip of Cape York Peninsula, Australia.
We had just finished dinner around a campfire, sheltering behind a tent from periods of light rain which came and went. The Moon was almost full above the horizon, ducking in and out of clouds. Aboriginal Rangers, environmentalists, and campaign workers were excitedly discussing a new campaign to return Aboriginal lands and seascapes to their traditional owners, and better ways to protect and manage our special areas like the Great Barrier Reef, the largest and some of the oldest Rock Art galleries in the world, and so on.
Suddenly someone shouted, “Come and have a look at this!”, and we all ran over to see a perfect moonbow over the hills between the beach and Lockhart River community (Letters, 29 April and 20 May). It appeared as a well-defined, pearly white band. The sky inside the arc was a faint-deep-blue. Outside the arc the sky was a darker blue fading to black away from the arc. The Moon was partly behind a small cloud over the Barrier Reef 鈥� a beautiful sight through the palm trees along the beach.
After about ten minutes the Moon came out from behind the clouds, and the moonbow faded.
None of us had ever seen or heard of such a thing before. We happily agreed that it must be a wonderful omen from the heavens blessing the campaign.
Imagine my delight and surprise after several weeks in the bush, to buy the latest copy of New 杏吧原创 (20 May) from the newsagent in Cooktown to find three fascinating letters on moonbows! Thank you New 杏吧原创s contributors for explaining the phenomenon so well. I wish you could have all experienced the delight and awe we felt that night!
Race and reason
In your Comment of 27 May you write that scientists are using a spurious argument when they say that there is no justification for racism because only a tiny percentage of genes differ between the so-called races. You write that it is preferable to say, “We know from our daily experience that humans of all races are virtually identical and that there is no justification for racism.”
Surely the typical justification for racism is based precisely on the daily experience of people who very easily detect real differences between what they call races 鈥� skin colour and the rest are certainly not identical across the human population. The racist believes, not surprisingly, that these real differences reflect other, fundamentally important, differences and concludes that these imply superiority or inferiority.
So it is important to discover whether there are any such fundamental differences, and genetics provides evidence that almost certainly there are not. The genetic differences are not only extremely small as a percentage, they also indicate that the period of divergence among humans has been far too brief to allow for fundamentally important genetic differences to emerge. This short period of evolutionary divergence is consistent with our understanding of the dispersal during human prehistory and the pattern of human settlement.
Obvious differences such as skin colour involve very little genetic variation and are adaptive to different climates. Moreover, genetics reveals that within each of the human groups that the racist would distinguish, there exists vastly greater genetic diversity than exists between the groups. In other words, the genetic difference between any two individuals within such a group is vastly greater than the genetic differences between average members of two such groups.
I do not suggest that trying to explain the genetics would have a very useful outcome in the midst of a racist riot and I do not wish to devalue the argument that we can recognise that human diversity and empathy are universal through observation alone. But I do believe that the genetic explanation makes it easier to understand the origins of trivial genetic difference such as skin colour and helps to dispel the fears that feed racism.
Britain's decline
You are quite correct to remind the Tories that it was they who presided over the “century of relative decline” (Comment, 27 May). But they could be challenged much more strongly, especially on their view of the period 1945 to 1979 as a disaster area.
Nineteenth-century capitalism in both Britain and America never managed as much as 2 per cent regular annual growth. The relative decline referred to did not happen because we started doing anything worse. It was merely that other nations started doing significantly better.
Between 1820 and 1870, Britain averaged 1.2 per cent annual growth. America was edging ahead with 1.5 per cent. France limped along at 0.8 per cent and Germany at 0.7 per cent. From 1870 onwards, Britain did rather less well, while other nations began to do significantly better.
Between 1950 and 1973, Britain grew twice as fast as its best 19th-century average, achieving 2.5 per cent annual growth; but this superior growth still meant relative decline, since Germany managed 4.9 per cent and Japan an astonishing 8 per cent. Between 1973 and 1989 everyone grew less quickly, with Britain falling back to 1.8 per cent growth.
The success of Victorian Britain was based on a long period of relatively slow growth in the face of weak competition. Back then, we were the only real industrialised power, the “workshop of the world”. And during the first unfolding of industrialism, 1760 to 1820, (state expenditure was large and rising, and trade was heavily regulated.
The period of 1950 to 1975 was Britain’s best, both economically and socially. That other nations were doing even better in the same period need not have been a cause for regret. And all the effects of Margaret Thatcher and John Major have merely lowered our performance back towards Victorian levels.
Power problem
M. W Thring argues (Letters, 3 June) for replacement of fossil fuels by renewable energy sources including solar energy. But it is simple to demonstrate that solar energy cannot provide significant replacement. The following example should suffice.
Ratcliffe is a typical British coal-fired power station. It has a generating capacity of 1940 megawatts. Mean solar energy supply to the Earth’s surface is 347 watts per square metre (the solar energy is slightly less than this at Britain’s latitude). So, each 5.59 square kilometres of Britain receives energy from the Sun equivalent to the output of Ratcliffe.
Power equivalent to Ratcliffe would be obtained if 5.59 km2 of land were covered by solar collectors which were 100 per cent efficient. The ground beneath these collectors would be dark and would have a temperature like that of the North Pole in winter. So, it would need lighting and heating powered by more solar collectors; and more lighting and heating would be needed beneath these. This provides a “law of diminishing returns”.
The problem can only be overcome by using inefficient collectors. Indeed, they must be so inefficient that they do not make a discernible difference to the illumination and temperature beneath them. The collectors must not have an efficiency of more than 0.01 per cent. Otherwise, they would make a detectable change to the climate beneath them.
Mean British temperature is about 280 K (about 7 掳C) and 0.01 per cent of this is 0.028K (0.028 掳C). A reduction in temperature of less than 0.03掳C would not be significant, but 0.1掳C colder would be a discernible 鈥� and unpleasant 鈥� climatic change.
A solar collection efficiency of 100 per cent requires a collection area of 5.59 km2. So, a collection efficiency of 0.01 per cent requires a collection area of 55 900 km2. The area of Britain is 242 429 km2 if the Channel Islands and Isle of Man are included. So 55 900 km2 is 23 per cent of Britain.
Simply replacing Ratcliffe power station with solar energy collectors would cover nearly a quarter of the UK with the collectors. But Ratcliffe is only a typical one of Britain’s 19 coalfired power stations, and then there are the gas-fired power stations, and then there are the car engines, and then 鈥�
Bad bet
The proposed bet between Julian Simon, Paul Ehrlich, and Stephen Schneider (Comment and This Week, 3 June) fills me with a sense of dejection.
The choosing of statistical trends to prove or disprove world doom is an extremely dubious method. Effectively if they wanted to, they could prove any scenario by being carefully selective in the trends they choose. The very fact that they cannot decide on the trends leads me to believe that neither party is really sure of what will happen. But then, who is?
Looking at the arguments it seems that Simon is particularly at fault in his conjecture that economic expansion could continue indefinitely. The economic system is simply a subsystem of the environmental system (a fact long recognised by environmental economists); the latter constrains the former.
It seems therefore that the issue at hand is that of the quality of development rather than quantity. This, however, implies nongrowth.
The two sides of the argument, as always, have very valid contributions to make to the debate, but tit for tat statistical arguments will not do anything to improve public understanding of the issues involved. The two factions should get together and for once produce a multi-sided picture with balanced ideas.
You do not list all the indicators proposed by Ehrlich and Schneider, but if those you mention are anything to go by, such as a decrease in acreages of crop land or a decline in rice and wheat yields per person, it is difficult to accept Julian Simon’s contention that they do not directly relate to human welfare.
Almost any indicator expressed per person is bound to show a deteriorating situation, whether it is food per person or freshwater per person or space of any kind per person (land space, road space, air space, ski space, marina space, beach space) or blue whales per person or giant sequoia trees per person 鈥�
The key question is clear: What human populations, for the Earth and its regions, would allow the possibility for these indicators to improve?
Planetary chaos
Anthony Youngman writes that he has heard that planetary orbits are “chaotic over the long term” and that deterministic calculations would probably not even agree with Tycho’s observations 鈥� only 200 years ago” (Letters, 22 April).
Tycho actually flourished in the late 1500s, about 400 years ago. Further, the Solar System is fortunately not as chaotic as he thinks over a few centuries. The high-quality ephemerides at the Jet Propulsion Laboratory have uncertainties of only a few seconds of arc for Neptune and Pluto and substantially less for the inner planets.
Calculations can accurately predict the positions of the planets for thousands of years, and programs are available for laptop computers that do so. As Timothy Ferris writes in the June Scientific American, “The publisher credibly states that [the] RedShift [program] can predict the locations of the inner planets to within 30 arc-seconds on any date between 4712 BC and AD 10 000.” That uncertainly is about one-sixtieth the diameter of the Moon, and is comparable with Tycho’s naked-eye resolution, about one arc minute, over a time-scale dozens of times longer.
For relatively longer times, millions of years, the situation is different: the worst case is the Moon because of the tidal force from the interaction with the Earth; this interaction causes a deceleration in the lunar longitude. The resulting uncertainty grows quadratically at the rate of nearly a kilometre per century-squared. After only 100 000 years or so, the position of the Moon in its orbit is completely unknown.
Predicting the planets is better, but still limited. With our present knowledge and abilities, we lose track of the inner four planets (where they are in their orbits) after tens of millions of years; sooner for the outer planets.
Finally, when one considers billions of years, it seems that there is even a chance that Mercury or Mars may escape entirely from the Solar System. For the Earth, Venus, and the four Jovian planets, things are more stable.