Meat and climate

According to the UN, animal agriculture is responsible for 14-18% of global greenhouse gas emissions - more than all forms of transport combined.

Sheep and cows emit large amounts of methane - a greenhouse gas 30 times stronger than carbon dioxide at trapping heat in the atmosphere - which contributes to climate change.

The production of fertiliser for crops used to feed animals, petrol to power the trucks that take them to slaughter, and electricity to freeze their carcasses also requires huge amounts of fossil fuels, releasing huge amounts of carbon dioxide into our atmosphere.

Scientists agree that plant-based foods have a smaller carbon footprint than their animal counterparts, so the easiest way to curb climate change is to eat plant-based.

Animal agriculture also has a shocking water footprint. On average, each meat eater is responsible for using 15,000 litres of water a day. While it takes about 1,790 litres of water to grow 1 kg of wheat, we need more than five times as much water to grow 1 kg of beef. That's the equivalent of 50 bathtubs full of water to produce just one steak. And it takes 72% more water to raise cows for milk than it does to produce soy milk.

Most of the pesticides, herbicides and other chemicals used on feed crops return to the environment via wastewater and excreta, contaminating soil and water worldwide, causing soil degradation, harming human health and marine life, creating ecological "dead zones" in the oceans and killing wildlife such as fish, bees and amphibians.

The UN recognises that animal agriculture is one of the biggest contributors to water pollution. Run-off from meat, egg and dairy farms pollutes rivers with faeces, urine, pathogens such as E. coli, antibiotics and other drug residues.

Ammonia gas, which comes from Denmark's cattle, chicken and pig farms, is a deadly air pollutant that threatens human health and can cause premature death.

Animal agriculture has the world's biggest footprint on the planet. It occupies a third of the Earth's land surface and is responsible for 30% of biodiversity loss. Agriculture is the most frequently reported threat to wildlife and WWF has identified habitat loss as the leading cause of species extinction.

Wild animals are running out of space to live and species are going extinct at an alarming rate. But despite this crisis, humans are still tearing down some of the most biodiverse areas on Earth - including rainforests in South America - to graze cows or grow soya for animal feed. As much as 90% of the world's soya crops go to cows, chickens, sheep and pigs. By moving away from raising animals for food, we can stop deforestation, fight the climate crisis and preserve the natural habitats of many animals.

Mistreatment of nature can have devastating consequences for human lives. Commenting on the COVID-19 pandemic, leading biologist Professor Thomas Lovejoy said, "This pandemic is the consequence of our persistent and excessive interference with nature and the widespread illegal trade in wildlife." Other scientists have pointed out that deforestation, intensive farming, exploitation of wildlife and uncontrolled expansion of agriculture are creating the "perfect storm" for disease outbreaks originating in other animals.

Fishing vessels are decimating the world's oceans, leaving them empty, lifeless and on the brink of ecological collapse. At this rate, with an estimated 90% of fish stocks fully exploited, there won't be many more fish in the sea.

A recent report described discarded fishing gear as "the most harmful form of marine litter for animals". This equipment - also known as "ghost gear" - maims and kills millions of marine animals every year.

Fish farms are not sustainable either. Farmers who raise salmon feed them three times their weight in wild fish. Fish on farms live in overcrowded, filthy enclosures and suffer infections from parasitic lice, diseases and debilitating injuries. Conditions on some farms are so appalling that up to 40% of fish die before farmers get to kill them.

The world is facing a food shortage that hits the poorest people hardest. Yet every year, 760 million tonnes of grain are fed to factory farm animals so that people can eat meat, dairy products and eggs. This is terribly inefficient: it can take up to 16kg of grain to produce just 1kg of meat. The world's farmed cows consume an amount of food equivalent to the calorie needs of 8.7 billion people - more than the entire population of the planet. If grain was used directly to feed people instead of being passed through farm animals, there would be more than enough food for everyone.