We humans eat about 230m tonnes of animals a year, twice as much as
we did 30 years ago. We mostly breed four species – chickens, cows,
sheep and pigs – all of which need vast amounts of food and water, emit
methane and other greenhouse gases and produce mountains of physical
But how much stress does our meat-eating put on ecological systems?
The answer is a lot but the figures are imprecise and disputed. In 2006,
the UN calculated that the combined climate change emissions of animals bred for their meat were about 18% of the global total – more than cars, planes and all other forms of transport put together.
It's an accounting nightmare but depending on how it's done, livestock's
contribution to climate change can be calculated as low as 5-10% of
global emissions or as high as 50%. Last year, a Food Climate Research Network report concluded
that UK meat and dairy consumption was responsible for 8% of the
country's total greenhouse gas emissions. But however it's counted,
livestock farming ranks as one of the three greatest sources of climate
changing emissions and one of the largest contributors to environmental