Isabella Tree is misguided in thinking veganism encourages the eating of “industrially grown” crops (If you want to save the world, veganism isn’t the answer, 25 August, Journal). In reality veganism reduces the eating of such crops, as those are exactly what are fed to livestock at the density current in Britain. The amount of soya fed to the average cow to produce a litre of milk is several times that used to produce a litre of soya milk, so switching to soya milk reduces demand for soya imports. Only once consumption of meat, dairy and eggs falls below a quarter of current levels need she worry about impacts on her kind of farming.

Even then the kind of animals that she farms might find a niche outside being farmed. I have no idea whether she sells the meat of her Exmoor ponies for human consumption, but the excessively meat-eating majority include plenty who would refuse it. Cat and dog meat is not generally eaten in Britain, but it still has those animals.

If vegans reach a big enough majority, the thinking behind eating plants directly rather than eating what eats them might lead to keeping the animals that cats and dogs eat. That might be rabbits for those who still want a traditional pet, sheep for those who want something large but docile, pigs for those who want a challenge.

For now, veganism can be seen as compensating for all those whose consumption of steaks – and cheese, omelettes and the rest – is far from “occasional”. It is not compensating nearly enough, nor will it be until we reach that majority, but it is all that one individual can do.

Charles EL Gilman

Mitcham, Surrey

• Although Isabella Tree’s views on veganism will upset some, wasting edible pests (eg rabbits) is difficult to condone given growing risks to food supplies. Livestock’s impact (numbers and/or impact per head) needs reduction but this needs investment and changed attitudes. Yet supposing hi-tech methods allowed large-scale synthetic food (not just meat) to be produced, problems still remain.

Such food wouldn’t benefit the world’s poor, while rainforests could be cleared for biofuels, other cash crops, minerals, logging and dams. Such threats apply elsewhere, along with suburban sprawl and other development (These projects shape our lives. But we have no say in them, Journal, 22 August), fracking and water abstraction. Rewilders could be outbid by those aiming to give everyone western lifestyles and the jobs to afford them.

With gas escapes from ice sheets and the need to re-home climate change refugees, food security and conservation will both struggle. Tree’s ideas are not silver bullets but, along with restoring fish stocks, could provide safety nets against severe crop losses since free markets can’t handle gluts and nobody is clearly responsible for food security.

Iain Climie

Whitchurch, Hants

• Isabella Tree puts forward a compelling case for us being omnivores; our natural teeth structure is to eat meat and veg, which fits us into the cycle of life. Her comments about soil structure remind me of John Steinbeck’s The Grapes of Wrath – there were other factors in the Oklahoma dust bowl, but the bad farming practices inflicted misery on many thousands of people in America in the 1930s. Hopefully, we will save the soil structure in the UK by extensive farming and being our natural selves, omnivores.

Andrew Parker

Truro, Cornwall

• Could Monsanto et al be behind the relentless drive to veganism? Scarlett Conlon reports (18 August) that the fashion industry is creating mass-market synthetic leather from genetically engineered yeast and pineapple leaves. They will also need to find ways of producing artificial, plant-based wool.

Vast numbers of new factories will be required to mechanically replicate milk, butter, cheese, eggs, meat, leather, wool and feathers, producing highly processed foodstuffs and engineered materials to replace all natural animal products.

And what of fish? Will cats be allowed to eat them? Will it be acceptable to use human excrement as an organic fertiliser base, replacing animal dung, blood, hooves and horns?

In the new puritan, domestic-animal-free world, will down, moor and pastureland, with the ecosystems they support, be replaced by endless GM crops and factories?

Judy Stevens

Brighton

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