Letter: The climate cost of cheese in context (1)

From Keith Ross, Villembits, France

You illustrate the carbon footprint of a kilogram of cheese and other foods (16 February, p 30). It would be more useful to see the carbon footprint per kg of dry mass.

I estimate that milk (90 per cent water) has an impact of 12.5 kg of CO₂ equivalent per kg of biomass; cheddar cheese (37 per cent water) an impact of 13.8; chicken (65 per cent water) 14.2 and pork (65 per cent water) 17.8.