Sir — In the Commentary “Agriculture ofthe future” (Nature 428, 215–217; 2004),T. C. Tso argues that the Chinese governmentshould use the country’s three mostimportant resources — people, land andwater — to their best effect. We agree withthis general principle. But we have threereservations regarding turning the Xinjiangregion into the “California of China”.

First, the author gives the impressionthat Xinjiang is largely undeveloped andhas “abundant resources”. Yet the area ishome to 11 people per km2, far exceedingthe international population-densitystandard for arid areas of 7 people per km2. Some 95% of the population live in oases totalling less than 60,000 km2.The population density in oases, at 292 inhabitants per km2, reaches that of many coastal cities. Far from being“undeveloped”, the area is denselypopulated and would have difficultyabsorbing new migrants. Also, far fromhaving “abundant resources”, it alreadyexperiences pressure on water sources.Large-scale agricultural expansion will

require large amounts of water that arecurrently not available. Tso argues for thediversion of water from southern China,but this has the potential to create greatecological harm and international conflict,as discussed by A. Chen and C. Chen(Nature 429, 501; 2004).

Second, the arid Xinjiang region ismore ecologically fragile than Tso suggests.Desertification has increased as a directresult of overgrazing and unsustainablefarming practices. During the past 50 years the area of desert has increased by4,210 km2, at an average rate of 84.2 km2

per year, while lakes have decreased from9,700 km2 to 4,748 km2. Many famouslakes have actually disappeared.

The area’s main river, the Tarim, hasbeen steadily dwindling for 30 years as a result of dam building and irrigationupstream. This in turn has reduced thegrowth of vegetation, including ancientpoplar groves, that had long formed abarrier between two deserts. It is nowpossible that the Taklimakan desert and theKumtag desert will merge. Each year the

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frequency and intensity of dust stormsincrease, and the effects are felt as far away as Beijing, Tianjin, Korea and Japan.If more people move into Xinjiang, theproblem of desertification will inevitablybe exacerbated.

Finally, the large-scale migrationproposed by Tso could have seriouscultural implications. The Xinjiang region is inhabited by the Uighur people, the fifth largest ethnic minority in China. Immigration by ethnic Hanpeople could alter traditional ways oflife followed by the Uighur.

Development in Xinjiang requires anadequate understanding of its environmentand people. Turning it into the “Californiaof China” is not a viable option.Wenwei Ren*, Andrew A. Sacret†*Ministry of Education Key Laboratory forBiodiversity Science and Ecological Engineering,School of Life Sciences, Fudan University,Shanghai 200433, People’s Republic of China†School of Urban and Regional Planning,Queen’s University, Kingston,Ontario K7L3N6, Canada

Bermuda welcomescareful prospectorsSir — Despite the claim in your News story “Bermuda gets tough over resourcecollecting” (Nature 429, 600; 2004),Bermuda’s Ministry of the Environmenthas not shut down any research projectsrelating to biodiversity access, even on atemporary basis. New laws and regulationsare under development to enhancebioprospecting, not to prevent or hindersuch research activities.

Contrary to your News story, theMinistry of the Environment is notdispleased with Diversa’s research activities in Bermuda. The ministry greatly values the ongoing collaborationswith the Bermuda Biological Station forResearch (BBSR), and appreciates thestation’s responsibility in ensuring aproactive and consultative approach toissues of environmental access.Furthermore, Diversa, BBSR and theministry look forward to exploring ways ofexpanding the bioprospecting benefitsrealized to date by the people and thegovernment of Bermuda.Jack A. Ward*, Anthony Knap†, Jay M. Short‡*Ministry of the Environment, GovernmentAdministration Building, 30 Parliament Street,Hamilton HM 12, Bermuda†Bermuda Biological Station for Research,

Ferry Reach, St George’s GE 01, Bermuda‡Diversa Corporation, 4955 Directors Place,San Diego, California 92121, USA

Golden rule of economicsyet to strike prospectorsSir — Your recent News Feature“Bioprospects less than golden” (Nature429, 598–600; 2004) is the latest todocument the disappointments ofbioprospecting. It suggests that “new ruleson ownership” might give bioprospecting aboost. Our experience leads us to doubtthis conjecture. The reason commercialinterests are not willing to pay much forbiodiversity is that it is not worth much tothem. This may seem paradoxical, giventhat new products can be worth billions ofdollars, but our conclusion emerges fromseveral basic principles of economics.

First, the spectacular earnings availablefrom infrequent research successes mustcover the far more common failures.Second, even in bioprospecting, costs aredominated by specialized labour andequipment rather than the chemicalentities from which products are crafted.Finally, and most importantly, untestednatural chemical entities are not scarce,and for that reason, they should not beexpensive. A pharmaceutical researcher’s

willingness to pay for a natural productlead is determined by the probability that the lead will result in a useful newproduct multiplied by the probability thatthe same product would not be developedfrom any of the other leads available to theresearcher. When there are large numbersof potential leads, successes must either be so unlikely as to make searchingunattractive or so probable as to rendercompeting leads redundant. Either way,researchers will not pay much for anyparticular untested product.

Your News Feature emphasizes thatrules must be agreed for the allocation of genetic resources, and this is certainlyimportant. Yet the biggest practicalproblem with bioprospecting may beunrealistic expectations. Our sense is that governments and advocates indeveloping countries have often beenmisled about the value of their biologicalwealth. Consequently, they hold out forspectacular gains that they are unlikely toachieve, and all too often forego the moremodest but more readily achievablebenefits such as those that your NewsFeature describes as arising from PhyllisColey’s programme in Panama.David Simpson*, Roger Sedjo†*Department of Economics, University CollegeLondon, Gower Street, London WC1E 6BT, UK†Resources for the Future, 1616 P Street NW,Washington DC 20036, USA

Migration won’t make Chinese deserts bloomDiverting water is not enough. Fragile land such as Xinjiang needs care, not exploitation.

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© 2004 Nature Publishing Group