In this book, the author talks about how eating meat affects the world's environment globally. I don't get why eating meat is harmful to the environment. Please explain specifically. Thank you.
As you have not mentioned the title of a specific book, I'll focus this answer on the evidence for the ways in which eating meat affects the environment. The evidence is overwhelming that carnivorous diets have a greater negative environmental impact than vegetarian ones.
The first way in which meat consumption has a negative impact on the environment has to do with what agriculture professionals term feed conversion. This is the amount of plant food needed to produce a pound of human food:
- Eating plants: if you eat 1 pound of plant food, you get the full caloric content of the one pound of plant food.
- Chicken: A chicken needs to consume 2 pounds of plant food to create one pound of meat.
- Pork: A pig eats 3.5 pounds of plant feed to produce one pound of meat.
- Beef: Cattle need to consume 6 pounds of plant material to make 1 pound of meat.
What this means is that it is much more efficient to eat plants yourself rather than to have an animal eat plants and then to eat the animal. All the environmental impacts of farming, including use of water, fertilizer, and fuel for farm equipment, are multiplied by a factor of two to six in a meat-based diet.
Next is the problem of methane. Cattle, because of the nature of their stomachs, produce methane gas (i.e. flatulence) as they digest food. Methane is a major greenhouse gas contributing to global climate change. A cow contributes as much in the way of greenhouse gases to the atmosphere in a year as a car burning 325 gallons of gasoline.
In certain types of mixed use farms, chickens can have minimal environmental impact, as well-managed egg production can be quite environmentally efficient, especially when it is part of a small mixed farm which grows a variety of produce and has free range chickens consuming insects and leftovers. Eating hens too old to lay eggs or extra roosters in that case is not environmentally harmful.