Are recent trials in the UK on genetically modified crops a sham ? A new analysis published by environmental group Friends of the Earth yesterday suggests that the four year long evaluations 'will fail to provide any conclusive evidence on whether GM crops will do long-term harm to farmland wildlife.'
The main thrust of the Friends of the Earth argument comes from its belief that the ecologically significant differences between GM and non GM crops may be missed because the experiment lacks sufficient statistical power and meaningful difference between indicator species.
The trials involved farmers growing both conventional and GM varieties of sugar beet, maize or oilseed rape (canola) in neighbouring fields. There were up to 25 sites per crop per season, which researchers would regularly visit to count weeds, beetles and other biodiversity 'indicators'. The goal was to discover if the GM fields held significantly less, or more, wildlife than those with conventional crops. But,as the science journal New Scientist questions in an article on the GM trials published yesterday, what counts as 'less' or 'more'?
For weeds and insects, the scientists designed the trials to be sensitive enough to have an 80 per cent chance of detecting 1.5-fold differences between conventional and GM fields. However, writes the New Scientist the report claims this sensitivity target is unlikely to be met for every species because of 'noise' in the data.
Based on the trials' own pilot observations, the report claims that levels of some key indicator organisms, including beetles and broad-leaved weeds, are likely to vary from field to field by far more than the 50 per cent margin that the trial allows for. If so, that could make detecting a 50 per cent difference between GM and non-GM fields impossible even if the difference is there, suggests the New Scientist.
Friends of the Earth Real Food and Farming campaigner Pete Riley said: "We have published this report because we think it is vital that the public, farmers and the Government realise the limitations of the Farm Scale Evaluation results. "
"This is not the fault of the researchers - their hands were tied," he added. Riley claims that because the UK government wanted to avoid the threat of a moratorium - also currently a sensitive issue for many other governments across Europe - it chose to avoid a proper investigation into the long term impact of GM crops.
But Les Firbank, who co-ordinated the trials from the Institute of Terrestrial Ecology in Cumbria in north-west England, told the New Scientist. "They're speculating on whether the experiment has been capable of delivering the stated power. That won't be answered until the data are published."