Sir

In your editorial on the debate over genetically modified foods, you say “the steady reduction of biodiversity remains a silent witness to the potential of modern agriculture to inflict damage on the environment and the wildlife it supports” (Nature 398, 639; 1999 ). It is unfair to attribute solely and without qualification to agriculture an effect that is correlated with a whole raft of land-use changes and also with climate change.

Many farmers take great care over the countryside. You can also argue that city dwellers contribute to the reduction in biodiversity by demanding more housing development, more motorways, and so on.