Advantage of burning gas over coal is easily lost

Sir, Yumehiko Hoshijima (Letters, March 21) is correct to challenge the myth that shale gas is going to benefit cimiate change. If median emissions exceed 2 per cent of production, then the advantage of burning gas over coal is lost. Satellite observations over the US have demonstrated that exploratory fields release higher amounts of methane then established fields, with losses over Bakken and Eagle Ford representing 10 per cent of production.