Water for cattle
Rachel Nowak cites Barney Foran and talks in vague terms about Australia’s profligate use of water “to make products such as food, drink, clothing and newspapers” (16 June, p 8). Looking at actual data makes it obvious what is happening.
For example, a 2004 study by CSIRO () shows (p 73) that the dairy industry’s extraction of water from the Murray-Darling basin grew from 2500 gigalitres in 1996-97 to 4200 gigalitres in 2000-01. To put this figure in perspective, all the towns and cities in Australia use about 2300 gigalitres per year. That 4200 gigalitres was 35 per cent of all the Murray-Darling Basin water. The 2005 report Balancing Act, which Foran co-authored, put the beef and dairy industry’s water use at 6700 gigalitres based on 1995 data (and that is only counting “extracted” water).
Nowak mentioned Graeme Pearman saying that we need to consider the impacts of our population of 21 million people. Our population is 21 million people plus 28 million cattle, and it’s the cattle that dominate our water use.
Dust to dust
Feedback speculates on connections between dust-bunny formation and that of solar systems (2 June). This amounts to nothing less than heresy, implying as it does that the intelligent designer is little more than a poorly performing contract cleaner.
Easy birthday odds
Justin Mullins mentions (9 June, p 53) the birthday paradox: how many people do you need for the odds to be better than 50:50 that two share a birthday? There is actually an easy proof. I learned this from the chemist Linus Pauling while a postdoc at Caltech in 1956 at the chemistry department annual picnic. My wife Charmian and I were chatting with Pauling when he announced: “There are so many people here that it is almost certain that two will have the same birthday”. My wife, being less aware of Pauling’s eminence, cried out “Nonsense, I don’t believe you.” He replied “Let’s test it. My birthday is 28 February.” This happens also to be my birthday, whereupon Charmian accused him of having looked up my records in the Department’s files to support his joke.
The proof is as follows: given two persons, the chance that they will not have the same birthday is 364/365. For three persons the chance of no common birthday is (364/365) 脳 (363/365). If you iterate the product to 22 terms, the result is 0.4927. Thus for 22 persons, the chance that two will share a birthday is (1 鈥� 0.4927) or 0.5073, in other words, better than 50:50. You can readily check this with a hand-held calculator
Fighting resource entropy
Your “Earth audit” has me seriously concerned, as perhaps it should (26 May, p 34). It was pretty clear we could not give everyone on the planet a car, but I thought we might manage a cellphone and have continued economic growth selling intellectual property to run through it.
Now it seems this vision is doomed, perhaps in my lifetime, by the second law of thermodynamics. Recycling programmes will leak, and precious elements will disperse beyond the possibility of conventional collection.
There may be some hope, however. We can create rare elements in accelerators or reactors, we can look for them in space, or as Lynne Macaskie is doing, we can use biological processes.
I propose going further. Since heavy metals and pollutants accumulate in top predators, we could engineer an entire ecosystem to take advantage of this. Bacteria would extract metals from dust, while a succession of moulds, insects, birds and fish would return the material to collection points for reprocessing.
Meanwhile, we’d better start paying a bounty on old mobile phones to stop people throwing them off the pier.
From Chris Rhodes
I am amazed by David Cohen’s timely article showing how limited are the quantities in mining reserves of metals on which our technology depends utterly.
Platinum is an interesting case, since 88 per cent of it comes from just two mines in South Africa, and world annual production amounts to just 150 tonnes. If the intention did exist to switch all 500 million road vehicles over to fuel cells, this would be hampered by the amount of platinum that could be made available for the purpose.
Even if current platinum production were doubled, it would be enough for no more than 2 million vehicles per year, or 50 million in 25 years. Just 10 per cent of the current number could be fitted by the time we are seriously running out of oil.
Clearly fuel-cell technology will not come to the aid of preserving the world’s vast transportation fleet, which will need to be curbed by probably 90 per cent. Details of these and other related calculations can be found at my blog ().
Reading, Berkshire, UK
Organic energy
Colin Shaw’s suggestion that there is little difference in energy use between “conventional” and organic agriculture (2 June, p 26) appears to ignore research that has come to the opposite conclusion. Recent life-cycle analyses at Cranfield University in the UK, for example, show that organic farming uses about 30 per cent less energy than non-organic per tonne of cereal or vegetables produced, and about 25 per cent less for meat and dairy products.
Many criticisms sometimes levelled at organic farming 鈥� such as the suggestion that it means a return to 19th-century methods or that it could not feed the world 鈥� do not stand up. Careful management allows organic agriculture to achieve high standards of pest control, nutrition and production.
Organically farmed soils retain more water than conventionally farmed ones do, making organic agriculture more drought-resistant and less in need of irrigation. A review of research presented at a recent conference on organic farming and food security organised by the UN Food and Agriculture Organization confirms that widespread organic farming would slightly increase global food production.
We agree with Shaw’s point that it is important to localise food production, but this is difficult to do with large, specialised, industrial non-organic farms geared up for the commodity trade.
Bristol, UK
For the record
鈥� An editing error had us blaming aviation fuel for noxious air in planes (23 June, p 5). In fact organophosphate additives to engine lubricants are widely suspected.
鈥� We said that “Canada is finalising a C$1.9 billion ($1.7 million) class-action settlement” of Native Canadian claims (5 May, p 11). The US dollar figure should of course have been $1.7 billion.
鈥� In the article on denial-of-service attacks, we mentioned the Russian website Xakep (9 June, p 30) and should perhaps have noted that the name is pronounced “hacker” if read as being in Cyrillic characters.
Talking of genes
Unless I misunderstood it, your article on a “gene for speaking Chinese” illustrated what the late Stephen J. Gould would have called a naive adaptationism (2 June, p 15). This is the idea that one gene maps to one function which has one obvious selective advantage.
The article suggested that a recently evolved gene that correlates with using a non-tonal language, and with poor ability to learn tonal languages, could only have been selected for if non-tonal languages were somehow more advantageous than tonal ones. Since this is not obviously the case, the matter was described as a puzzle.
There is at least one other possible explanation, namely that the languages themselves could have acted as the background to selection of the gene. The “atonal” gene variant may have some completely different advantage. Where tonal languages are spoken, that variant would manifest as a gene “for” poor language abilities, which would inhibit its selection. Elsewhere, it would not suffer this handicap and could be selected for due to its other, as yet unknown, advantage.
To put it another way, memes would be conditioning genes.
Pacific voyagers
You report an analysis of chicken bones found on the Arauco Peninsula in south-central Chile which supports the idea that they were introduced to the Americas by Polynesians (9 June, p 23). The presence of the sweet potato Ipomoea batatas throughout Polynesia before the arrival of European voyagers offers further evidence of Polynesian contact with South America. The Incas of Peru and the Maoris of New Zealand both use the word kumara for this plant. Further confirmation of this contact is given by the presence of the totora reed and the medicinal plant Polygonum acuminatum on Easter Island. Both plants served identical purposes for the Incas and the Polynesians.
Canadian fission
Describing the decision by the Royal Society in London not to publish a paper on nuclear fission during the second world war, David Cohen says that Lew Kowarski, one of its authors, remained at the Cavendish Laboratory in Cambridge until 1946 (9 June, p 10). In fact, Kowarski went to Canada in August 1944 to work on the Atomic Energy Project of the National Research Council of Canada, building the Zero Energy Experimental Pile (ZEEP) reactor at Chalk River, Ontario.
ZEEP went critical on 5 September 1945. Kowarski then returned to France, where he directed development of the ZOE reactor. ZEEP was a heavy-water moderated reactor that was developed as a proof of concept for the much larger and more important NRX reactor, which went critical in 1947. ZEEP was decommissioned in 1970, and dismantled in 1997. It is now on exhibit at the Canada Science and Technology Museum.
Water and life
I enjoyed your article about the materials that alien life forms could be made of (9 June, p 34). I have long felt that looking for life forms based on the carbon/water chemistry of Earth is somewhat narrow-minded, if experimentally sensible.
I do feel, however, that when describing the possibility of life forms that do not need water you missed one vital property of water. It is, as far as I’m aware, the only fluid that becomes less dense when it solidifies. This protects water beneath ice from freezing. Had water lacked this property, the oceans could have frozen solid, leaving only the simplest life forms 鈥� those that could survive being frozen for a long time 鈥� to continue evolution.
I agree that life can form in any place, even one devoid of water or carbon. However, when we are looking for intelligent life, we can limit ourselves to those planets that would support evolution, either through this protective property of water or in some medium that is not susceptible to freezing at all.
From David Prichard
How could an alien form of life be recognised as life if it is dissimilar to terrestrial life forms? As a youngster at school, I learned that for something to be recognised as living it must exhibit seven vital functions: assimilation, excretion, growth, locomotion (movement), reaction to stimulus (irritability), reproduction and respiration. To discuss the possibility of alien forms of life only in the context of these criteria is, I suggest, to prejudge the question of what we’re looking for. The statement that “complexity requires a nervous system… and a nervous system requires oxygen” may be equally limiting. The article rightly ends by quoting Dirk Schulze-Makuch, referring to the possibility of life on Titan: “We would have to refine our understanding, so we know what to look for.”
I suggest a more fruitful direction for cosmological research might be to look for intelligence 鈥� and, if it is found, to seek to understand the ways in which it evolved 鈥� rather than to presume the physical attributes of what is sought.
Geraldton, Western Australia
Whale tale
Peter Aldhous writes that the Japanese government proposed that four villages be allowed to begin “small-type” whaling (9 June, p 21). In fact the coastal towns in question 鈥� by no stretch of the imagination can they properly be described as “villages” 鈥� never ceased whaling. Their entirely commercial industries were based on catches of minke and Baird’s beaked whales; the latter are bottlenose whales, larger than the North Atlantic species whose meat used to be sold by Norwegian whalers to the UK as pet food.
When the International Whaling Commission set the catch limit for minkes to zero in 1986, the government of Japan unilaterally increased the national beaked whale quota to compensate. It could do this because Japan 鈥� along with Denmark and some other states that wish to continue the killing of beluga, pilot whales, narwhals and the like 鈥� does not recognise the jurisdiction of the IWC with respect to what it calls “small cetaceans” 鈥� even though the beaked whale is actually bigger than the minke. This is just one of the many anomalies that cause the IWC to be less effective than it might be.
Boycott or not?
Shame on the UK’s University and College Union for discussing a boycott of Israeli institutions (9 June, p 5). Whatever happened to the free dissemination of scientifically established truth for its own sake? It is never OK for science, as a whole 鈥� in an organised way 鈥� to withhold evidence. Individual scientists, of course, may act and speak according to their consciences.
It is short-sighted of you to ignore how complex this is. There are academics on all sides (there are more than two) who have valid, complex positions on “denial of education rights”.
From Mike Barnes
You are right that discussion of an academic boycott of Israel needs to take place, and a debate is what the University and College Union’s congress has called for. There are two points to debate, not just one.
First, to many, Israel’s actions since its occupation of the West Bank and Gaza in 1967 are indeed severe enough to support a boycott, especially in the academic context, because of the hugely negative effect of West Bank checkpoints, roadblocks and the so-called “separation wall” on the school and university education of young Palestinians.
The second is whether Israel is open to pressure to change its policies. The answer is that Israel appears completely impervious to any pressure to relax its closure policies or reverse its occupation of Palestinian lands. It has consistently ignored dozens of UN Security Council and General Assembly Resolutions to that effect over the years, and in 2004 ignored the advisory ruling of the International Court of Justice that the building of the wall was illegal and should be reversed.
It is this total inability to influence Israel’s illegal and brutal occupation that has led people to conclude that, in extremis, the only course of action is boycotts, among them an academic boycott. There are good precedents going back as far as the boycott of slave-produced sugar from the West Indies in the late 17th century.
Watford, Hertfordshire, UK
Trading vs standards
You are to be applauded for the absence of hot air in your coverage of the environment, but one myth did manage to make its way into your report on the poll gauging US public attitudes to different means of reducing carbon emissions (23 June, p 16).
You report Denny Ellerman of the Massachusetts Institute of Technology as saying that the US experiment with a cap-and-trade scheme to reduce sulphur dioxide emissions halved the cost to industry. It is true that the standards-based approach adopted in Europe cost twice as much, but it also managed to reduce emissions by twice as much as the US cap-and-trade method. The European and American schemes had about equal cost per unit of reduction.
Cap-and-trade is complex and prone to serious distortions when lobbying affects the setting of cap levels. Standards backed by legislation are not proven to be more expensive if you use comparable measures, and have the advantage that they are harder to evade.
Badger badger
The UK’s Independent Scientific Group on Cattle Tuberculosis has reported that wild badgers are not principally to blame for spreading TB to cattle in Britain (23 June, p 9). In other words, money has been wasted on ludicrously inept experiments and inappropriate gassing policies only to come up with the same conclusion as that reached by John Krebs and his team back in 1997. Even 30 years ago we knew enough about the natural history of badgers and the epidemiology of TB to see that a policy based on attacking badgers would be doomed to fail, as I outlined in an article in New 杏吧原创 at the time (17 November 1977, p 430).
We would all like to see the incidence of TB reduced in both badgers and the national herd, but success will not be achieved by bowing to political pressure from the understandably worried but scientifically ill-informed agriculture industry.