George Monbiot (On a vegan planet, Britain could feed 200 million people, May 13) quotes me as calculating that “while a diet containing a moderate amount of meat, dairy and eggs would require the using 11 million hectares of land (of which 4 million is arable), a vegan diet would require a total of only 3 million”.
He does not specify that these figures relate to chemical farming using artificial fertilizers and pesticides – practices he later says he does not support. I have also made estimates for organic vegan farming with green manure plowed directly into the soil, and for organic animal husbandry in which green manure is fed to dairy cows whose manure is composted, while pigs and chickens are largely fed with waste food. Both systems require approximately 6.5 million hectares of arable land to provide healthy food for all of the country’s inhabitants. The vegan system is slightly more efficient in its use of land, while the livestock system provides a more varied diet.
With the rising cost of artificial fertilizers, the need to stop using the fossil fuels they are made from, and dwindling insect populations, the organic option looks increasingly attractive. . If this were to happen, the remaining approximately 11 million hectares of grassland would be open to various land uses, such as nature reclamation, cattle and sheep grazing, tree planting, energy crops, etc. .
My guess is that rather than choosing to regenerate everything, as Monbiot suggests, most people would prefer a diverse, multifaceted landscape supporting a thriving rural economy.