Intensive and industrial animal farming also results in less nutritious food, it reveals, highlighting that six intensively reared chickens today have the same amount of omega-3 as found in just one chicken in the 1970s.
The study entitled Appetite for Destruction launches on Thursday at the 2017 Extinction and Livestock Conference in London, in conjunction with Compassion in World Farming (CIFW), and warns of the vast amount of land needed to grow the crops used for animal feed and cites some of the worlds most vulnerable areas such as the Amazon, Congo Basin and the Himalayas.
The report and conference come against a backdrop of alarming revelations of industrial farming. Last week a Guardian/ITV investigation showed chicken factory staff in the UK changing crucial food safety information.
Protein-rich soy is now produced in such huge quantities that the average European consumes approximately 61kg each year, largely indirectly by eating animal products such as chicken, pork, salmon, cheese, milk and eggs.
In 2010, the British livestock industry needed an area the size of Yorkshire to produce the soy used in feed. But if global demand for meat grows as expected, the report says, soy production would need to increase by nearly 80% by 2050.
The world is consuming more animal protein than it needs and this is having a devastating effect on wildlife, said Duncan Williamson, WWF food policy manager. A staggering 60% of global biodiversity loss is down to the food we eat. We know a lot of people are aware that a meat-based diet has an impact on water and land, as well as causing greenhouse gas emissions, but few know the biggest issue of all comes from the crop-based feed the animals eat.
With 23bn chickens, turkeys, geese, ducks and guinea fowl on the planet more than three per person the biggest user of crop-based feed globally is poultry. The second largest, with 30% of the worlds feed in 2009, is the pig industry.
In the UK, pork is the second favourite meat after chicken, with each person eating on average 25kg a year in 2015 nearly the whole recommended yearly intake for all meats. UK nutritional guidelines recommend 45-55g of protein per day, but the average UK consumption is 64-88g, of which 37% is meat and meat products.