21/04/2013 18:58 BST | Updated 21/06/2013 06:12 BST

Why an Earth Day Menu Shouldn't Include Meat

This Earth Day, 22 April, many environmentalists will be advocating the three R's - recycling, reusing and reducing. While these actions are important and worthwhile, we would be better off focusing on a different letter: V for vegan. When you see a vegan logo on something, it means that it's both animal - and environmentally friendly. The best way to honour Earth Day - and help your fellow Earthlings - is by going vegan.

According to a UN report, the meat industry is 'one of the top two or three most significant contributors to the most serious environmental problems, at every scale from local to global'. Just take greenhouse gases, for example: The livestock sector is one of the largest sources of carbon dioxide and the single largest source of both methane and nitrous oxide, which are, respectively, 25 and 300 times more potent than carbon dioxide. A study published last October by the European Commission found that switching to a vegetarian diet results in twice the carbon-emissions savings of switching to an electric car.

Vegans also use less water. It takes about 15,500 litres of water to produce one kilogram of beef, compared with just 1,000 litres to produce one kilogram of wheat. The UN report also calls the livestock industry "a key player in increasing water use" and "probably the largest sectoral source of water pollution". We can save more water by not eating a pound of meat than by not showering for six months.

The process of turning cows, pigs, chickens and turkeys into beef, pork and poultry requires a lot of water and also pollutes the water. According to some sources, animals raised for food produce approximately 130 times as much excrement as the entire human population. Animal waste is typically stored in giant lagoons that have been known to burst, spilling millions of gallons of putrefying animal waste into our rivers, contaminating our drinking water and killing marine life.

We can also save energy simply by eating vegan foods rather than meat, eggs and dairy products. It takes roughly 11 times fewer fossil fuels to produce a gram of plant protein than it does to produce a gram of animal protein. Turning animal skins into leather, which is a co-product of the meat industry, is about as environmentally friendly as an oil spill, requiring about 130 different chemicals, including highly toxic mineral salts, formaldehyde, coal-tar derivatives and various oils, dyes and finishes (some of which are cyanide-based).

Farming animals for their skin and flesh takes a terrible toll on the world's rain forests as well. The UN says that livestock production is a 'key factor' in deforestation, especially in Latin America, where vast swaths of rain-forest land have been cleared for cattle grazing. Today, approximately 30% of the Earth's land mass is used to graze animals or grow feed crops for them. It takes 20 pounds of grain to make a single pound of beef, 4.5 pounds of grain to make a pound of chicken meat and 7.3 pounds of grain to produce a pound of pork.

That grain could instead be used to feed hungry people. Vegfam, a UK-based hunger-relief charity, estimates that a ten-acre farm could support 60 people by growing soya beans, 24 by growing wheat or 10 by growing corn - but only two by raising cattle.

If you want to protect the planet - and help the people you share it with - go vegan. Not just on Earth Day, but every day. UN officials say that everyone will have to go vegan eventually in order to alleviate hunger, fuel poverty and the worst effects of climate change.

So why wait? Each vegan helps save the environment and spares the lives of up to 100 animals every year. Great-tasting vegan foods are good for us, too. They're cholesterol-free and generally low in saturated fat and calories. A healthy plant-based diet has been shown to prevent - and sometimes even reverse - heart disease, diabetes and cancer. If you care about the environment, animals or your health, celebrate Earth Day by being truly green - go vegan.