What price more food?

Letters– What price more food? From Niels Röling, Department of Communication and Innovation Studies, Wageningen University The analysis underlying Debora MacKenzie’s article “What price more food?” (14 June, p 28) disappoints. You “asked the world’s leading agricultural experts what it will take to boost yields”. The main answer you reported was: “invest in the science that can increase yields and in the infrastructure that can get the resulting technologies to the farmers who need them”. Yet the 2007 World Development Report and the International Assessment of Agricultural Science and Technology for Development Report (5 April, p 8) laid this “technology supply push” thinking to rest. True, the evidence does point to the need to increase the productivity of smallholders in developing countries. But what these people lack most is opportunity, which is denied them by skewed global trade and markets, and by inadequate institutions: credit, tenure laws, water rights, political representation, links to markets and so on. Higher crop prices benefit small farmers and rural labourers more than they harm poor consumers, making it more effective to provide safety nets for consumers than to deny small farmers a good price for their produce. Wageningen, The Netherlands From Gabriel Stecher Your diagram comparing yields of milk and meat with the quantity of grain needed to produce them is an over-simplification. Australian production of meat is dominated by grazing and foraging with low animal densities in parts of the continent unsuited to grain production. Sheep, goat, camel, emu and kangaroo are entirely free-range, and so is the bulk of beef. Of far more potential impact is the diversion of grains for ethanol 22 | NewScientist | 12 July 2008

production. As far back as 1979 I presented an analysis, later published in the CSIRO volume Energy and Agriculture, that showed that making ethanol from wheat has a negative energy balance under most conditions. Carboor, Victoria, Australia From Jody Mark Huston-Hall Is it not absurd that the human race depends on only four food groups – rice, maize, wheat and potatoes – for the majority of its calorie intake? As a permaculturalist I practise diversity, not only in the foods that I grow but also in the foods that I consume. Shoreham-by-Sea, West Sussex, UK

Oil prudence From Tom Radford, Bridgefield Consultants You suggest rather unfairly that oil companies deliberately underreport their reserves and mislead the public (14 June, p 4). In fact, the definition of “proved reserves” has for many years been very tightly defined by the Society of Petroleum Engineers and the World Petroleum Congress, and accepted by the Securities and Exchange Commission in the US for calculating a company’s assets. Proved reserves are defined as those quantities that “geological and engineering information indicates with reasonable certainty can be recovered in the future from known reservoirs under existing conditions”. Probabilistic addition of reserves within a portfolio is not permitted. The “existing conditions” include current market prices, operating costs and (where applicable) future capital expenditure, taxes, royalties and production-sharing agreements. Uneconomic oil, oil that will only break even if prices rise in future, and oil whose extraction depends on technology which is not currently employed in the immediate area must not be included. This conservatism is

justified by a history of rash announcements by overenthusiastic exploration companies, but more importantly it provides a common baseline for an industry that is widespread geographically and diverse in its application of technologies. As your report acknowledges, most companies use a range of measures for their internal accounting and for planning future developments. However, some of the risk factors bias the results in the same direction for all the projects in a portfolio. The current problems in the market for housing finance result from an assumption that the values of mortgages could be aggregated as if they were all statistically independent. Esher, Surrey, UK

Gay abandon From Gregory Hollin I am worried by the tone of your editorial “It’s a queer life” (21 June, p 5). In this instance, biology has given us the desired result by demonstrating that sexual preference is hard-wired, and that it is therefore incorrect to claim it is “unnatural”. The research mentioned is interesting and

then be open to endless criticism and repression? Or suppose that we found evidence for the infamous hypothesis put forward by biologist Randy Thornhill and anthropologist Craig Palmer that all men may be biologically hardwired to rape. Would this demonstrate that rape is in fact every man’s right? As evolutionary and other biological accounts become ever more prevalent in explaining social behaviour, the naturalistic fallacy is becoming a greater and greater problem. Leicester, UK From Graham Mounsey You rightly expressed concern about the views of Iris Robinson, chair of the Northern Ireland Assembly Health Committee, who believes that homosexuality is not natural and should be treated by psychiatrists. Equally concerning is the fact that her husband, Northern Ireland’s first minister Peter Robinson, recently appointed Sammy Wilson as his environment minister. Asked in an Assembly debate to provide “a detailed, peerreviewed paper in a respected scientific journal” that validates his climate change scepticism, Wilson declined because his evidence would take 10 minutes to present and “would bore the House stiff.” According to the official record he went on to say, “it is feared that if we use wind power, seals or fish may get sucked into the turbines.” Holywood, County Down, UK

Bias bias surely of value. But if, however, we go on to use “naturalness” as the basis for our definition of what is and is not “right”, trouble lies ahead. Suppose we never find a hard-wired biological cause for transgendered people. Would the lifestyle preference of this group

From R. A. Bailey I was one of the people interviewed for the UK’s Institute of Physics report on “gender friendliness” mentioned by Elizabeth Pollitzer (14 June, p 20). The experience suggested to me that the panel had firm, preconceived views about what makes a department “malefriendly” or “female-friendly”, www.newscientist.com