Can you save the earth by eating less meat?

  2015 is really a bad year for meat lovers. First, the International Agency for Research on Cancer (IARC) under the World Health Organization (WHO) issued a report at the end of October, listing processed meat as a primary carcinogen and fresh red meat as a secondary carcinogen. Then, at the end of the year, the United Nations held a climate negotiation conference in Paris. Animal husbandry was repeatedly mentioned as an important source of greenhouse gases. Some people even suggested raising the consumption tax on meat products to increase meat prices and curb consumption.
  Is meat really that bad? Let us first look at a set of data. The UN Food and Agriculture Organization’s survey report shows that with the increase in the total population and the improvement of living standards, the total global meat production increased from 78 million tons in 1963 to 308 million tons in 2014. At present, about one-third of the world’s arable land is used to produce feed for animal husbandry, and the total greenhouse gas emissions of animal husbandry account for 15% of the total emissions of human activities. The most important source is methane released from the stomach of cattle, which has a greenhouse effect 23 times that of carbon dioxide.

  Animal husbandry not only produces a lot of greenhouse gases, but also consumes huge amounts of water resources. According to statistics, every kilogram of beef needs to consume 10 kilograms of feed. If the water consumed by the cattle itself is counted in, it needs 15.500 liters of water to produce 1 kilogram of beef, which is almost equivalent to the amount of water in a small private swimming pool.
  But is meat really that bad? Not necessarily. Professor Vaclav Smil of the University of Manitoba in Canada believes that it is not possible to simply calculate the feed consumption, but also to take the quality of the feed into consideration.
  He pointed out in a book that a large area of ​​land is indeed used for animal husbandry, but a considerable part of it is not suitable for farming in the first place. The most appropriate treatment is to grow grass and then raise cattle and sheep. Ruminants such as cattle and sheep can digest the cellulose in weeds, but other animals (including humans) cannot. If properly managed, animal husbandry can become a sustainable agricultural production method, and the benefits to the environment are far greater than the development of those lands into farmland.
  In addition, the residues left after crops are harvested, such as straw and bran, can be used to feed cattle as long as they are slightly processed. Although pigs and chickens and ducks do not eat grass, they often consume food residues that humans do not eat. They also turn waste into treasure. In other words, we can think of livestock as energy converters. They convert energy forms that cannot be used by humans into energy forms that can be used by humans, and in this process create value for humans.
  As for the carcinogenicity of red meat, even if it is true, it cannot conceal the other benefits of red meat to humans. Beef is a very high-quality source of protein. An adult needs to eat at least 50 grams of protein a day. If he relies on beef, he only needs to eat 200 grams, which is equivalent to 407 calories. If he uses eggs instead, he needs to eat 9 eggs, which is equivalent to 566 calories. The highest protein content among vegetarians is beans. If he changes to kidney beans, he needs to eat 600 grams of beans, which is equivalent to 762 calories to meet his daily protein needs.
  In addition to the high protein content, the quality of the protein contained in beef is also the highest, containing all the essential amino acids for the human body, and the ratio is also the most appropriate. Not only that, beef also contains a lot of trace elements necessary for the human body such as iron and zinc, as well as two important vitamins, vitamin B6 and B12, the latter being quite lacking in almost all plant foods. To sum up, eating less meat is indeed good for the environment, but it is also not possible to avoid eating meat completely. Pure vegetarian food is not necessarily the most environmentally friendly.