Phillip Lymbery, author of Dead Zone, claims that we already rear 70 billion farm animals every year and demand for meat is projected to double in next 35 years. “Should we allow that to happen, the loss of wildlife will surely be incalculable. In addition to triggering the destruction of habitats, rising meat production is likely to accelerate one of the other big drivers of mass extinction: climate change.” Farm animals already contribute nearly 15 per cent of total greenhouse gas emissions, more than all forms of transport combined. But industrial farming contributes to climate change in other ways, such as the removal of ancient forests. Indeed, the WWF argue that deforestation and forest degradation causes up to 20 per cent of the world’s greenhouse gas emissions.