Livestock is a major contributor to greenhouse gas (GHG) emissions – a 2010 report by the United Nations Food and Agriculture Organisation (FAO) found that methane accounts for most of the GHGs emitted due to modern agriculture. And the largest source of this methane is from cattle. Livestock contributes to GHG emissions in other ways as well. Manure deposited and left on pastures is a major source of nitrous oxide emissions – emissions from manure in Asia, Africa and South America account for 81% of global nitrous oxide emissions.
Deforestation in South America is a leading cause of carbon dioxide emissions. The Amazon rainforest and forests of South America are being cleared in order to grow soybeans, not to meet the demand for tofu and soy milk, but to feed livestock. Only a small portion of soy is consumed directly by humans – most of it ends up as feed for pigs, chickens, cows and even industrially farmed fish. Most people are therefore consuming soy indirectly. However, the carbon dioxide emissions are only part of the problem of deforestation. In order to meet the global population for animal products, 4 million hectares of South America forests are destroyed every year, and eliminating fragile ecosystems at this rate threatens wildlife, biodiversity, indigenous people, water reserves and soil quality.
A study by WWF Germany (you will need to translate the page into English) found that the average consumption of meat by a German person a year requires 1,030m squared of land to meet this demand. Germans eat roughly the same amount of potatoes as they do meat, yet only 15m squared of land is needed to meet this demand for potatoes. With the rising global population, it is simply not sustainable to meet these demands for animal products.
The United Nations and WWF advise people to eat less meat in order to curb global warming. This would be an effective and reliable way to significantly reduce your carbon footprint, however, given the massive difference in GHG emissions and ecological destruction between livestock and plant-based foods, surely it would be better to cut out animal products completely? Indeed, this is one of the main arguments in favour of adopting a vegan diet, the more popular reasons being for ethical or health reasons.
A new study published in the journal Climate Change has confirmed this reasoning behind the vegan diet. The authors of the study compared GHG emissions attributable to more than 55,000 meat-eaters, fish-eaters, vegetarians and vegans in the UK. The researchers found that the dietary GHG emissions of meat-eaters were twice as high as those of vegans.
These high emissions are caused not only by methane from cows, nitrous oxide from manure and carbon dioxide from deforestation but also from the production, transportation and storage of animal products. There are high carbon dioxide emissions related to fossil fuels used to power factory farm machinery, for example. The report concluded that “reducing the intake of meat and other animal-based products can make a valuable contribution to climate change mitigation,” although, as was pointed out earlier, eliminating your intake of animal-based products is the most significant dietary way to reduce your carbon footprint. As much as bags for life should be encouraged, people should really pay closer attention to the food that goes in that bag. Your carbon footprint would be much less if you used plastic bags all the time, yet never bought animal products.
This new study adds to the body of evidence suggesting that a plant-based diet is the most eco-friendly diet. Another recent study found that “…reducing meat and dairy consumption is key to bringing agricultural climate pollution down to safe levels,” according to Fredrik Hedenus, one of the authors of the study. It logically follows from this that eliminating meat and dairy products will allow us to reach these safe levels much more quickly.
The co-author of the study, Stefan Wirsenius, says emissions can be somewhat reduced by more efficient meat and dairy production, but this reduction is relatively small compared to those that would be achieved by dietary change. As global population soars, more efficient agricultural methods will simply not be able to resolve the climate pollution associated with the high demand for meat and dairy products. It is estimated that by 2050 beef and lamb will contribute to 50% of global GHG emissions, whilst contributing to only 3% of our calorie intake. It is highly inefficient to use all of this energy and food to raise livestock, so that we can eat them later, rather than using these resources to feed ourselves.