Greenpeace has been invited by David Dennis, in Correspondence, to reconsider our opposition to genetically modified (GM) crops in the light of our support for the consensus on climate science (“Activists should accept mainstream view of GM” Nature 435, 561; 200510.1038/435561c). There are two factors to consider when deciding to support any apparent scientific consensus.
First, what was the process of arriving at the current mainstream position? In the case of climate change, uncertainties over the physics, measurements, modelling and historical data have generally (although sometimes erratically) tended to be resolved. In the case of GM, further investigation of genomes and gene function has led to new insights, such as alternative splicing mechanisms and the regulatory roles played by RNAi and chromatin packing, which question the fundamental understanding of gene regulation and control. This is demonstrated by the hedging on certainties in the UK government's GM science panel review in 2003, which was a far cry from the certainties expressed in the mid-1990s.
Second, as an environmental-protection organization, it should come as no surprise that we interpret scientific uncertainty in favour of environmental protection. Anyone who interprets a given level of uncertainty to propose a policy action must be imposing their values, even if that means advocating “do nothing now except more research”.
Whereas we are clear about our values, one might wonder what values are espoused by those, especially in the United States, who support GM organisms but reject the evidence of climate change.