Genetically modified crops: Fields of beaten gold IN AUGUST environmentalists in the Philippines vandalised a field of Golden Rice, an experimental grain whose genes had been modified to carry beta-carotene, a chemical precursor of vitamin A. Golden Rice is not produced by a corporate behemoth but by the public sector. Its seeds will be handed out free to farmers. The aim is to improve the health of children in poor countries by reducing vitamin A deficiency, which contributes to hundreds of thousands of premature deaths and cases of blindness each year. Environmentalists claim that these sorts of actions are justified because genetically modified (GM) crops pose health risks. Now the main ground for those claims has crumbled. Last year a paper was published in a respected journal, Food and Chemical Toxicology. It found unusual rates of tumours and deaths in rats that had been fed upon a variety of maize resistant to a herbicide called Roundup, as a result of genetic modification by Monsanto, an American plant-science firm. Other studies found no such effects, but this one enabled campaigners to make a health-and-safety argument against GM crops - one persuasive enough to influence governments. After the study appeared, Russia suspended imports of the grain in question. Kenya banned all GM crops. And the French prime minister said that if the results were confirmed he would press for a Europe-wide ban on the GM maize. But the methodology of the study, by Gilles-Eric Séralini of the University of Caen and colleagues, was widely criticised and, on November 28th, the journal retracted the paper (see article). There is now no serious scientific evidence that GM crops do any harm to the health of human beings. There is plenty of evidence, though, that they benefit the health of the planet. One of the biggest challenges facing mankind is to feed the 9 billion-10 billion people who will be alive and (hopefully) richer in 2050. This will require doubling food production on roughly the same area of land, using less water and fewer chemicals. It will also mean making food crops more resistant to the droughts and floods that seem likely if climate change is a bad as scientists fear. Organic farming - the kind beloved of greens - cannot meet this challenge. It uses far too much land. If the Green revolution had never happened, and yields had stayed at 1960 levels, the world could not produce its current food output even if it ploughed up every last acre of cultivable land. In contrast, GM crops boost yields, protecting wild habitat from the plough. They are more resistant to the vagaries of climate change, and to diseases and pests, reducing the need for agrochemicals. Genetic research holds out the possibility of breakthroughs that could vastly increase the productivity of farming, such as grains that fix their own nitrogen. Vandalising GM field trials is a bit like the campaign of some religious leaders to prevent smallpox inoculations: it causes misery, even death, in the name of obscurantism and unscientific belief. Follow your principles America takes little notice of this nonsense. But green groups in Europe, with the support of influential figures such as Prince Charles, have succeeded in shaping policy. Governments have hedged genetic research around with so many restrictions that much of the business has fled a continent that could be doing more than most to feed the world. Some developing countries - Kenya, India and others - have turned their backs on technologies that could literally save their peoples" lives. And European governments spend taxpayers" money financing groups encouraging them to do so. The group in the Philippines that trashed the rice trials, MASIPAG, gets money from the Swedish government. On moral, economic and environmental grounds, this must stop. In the field of climate change, environmentalists insist that the scientific consensus should frame policy. They should follow that principle with GM crops, and abandon a campaign that impoverishes people and the rest of the planet.