Animal agriculture has an enormous negative environmental impact.
It is responsible for 18% of worldwide greenhouse gas emissions, which is more than the entire transport sector including all cars, busses, trucks, trains, ships and planes. And methane gas, produced by animals like cows, sheep and goats, is up to 100 times more destructive to the atmosphere than carbon dioxide, over 20 years.
Animal agriculture is responsible for up to 33% of global fresh water consumption and 50% of worldwide grain consumption. Livestock and feed crops occupy 33% of the Earth's ice-free land, and is the leading cause of water pollution, ocean dead zones, deforestation, habitat destruction and species extinction.
This 2 minute video by Animals Australia explains the impacts of animal agriculture.
The world produces more than enough plant food to feed all humans. But because animal agriculture industries require huge amounts of feed crop, many impoverished people starve in countries where food goes to animals raised and killed for meat that is sold to wealthier nations.
Considering that meat, dairy and eggs are not required for human health, and increase the risk of chronic disease, this enormous negative impact on the environment and other people is completely unnecessary. If we purchase animal products, we finance these unnecessary negative impacts.
Each day, a person on a vegan diet saves 1100 gallons (4164L) of water, 45 pounds (20kg) of grain, 30 sqft (2.8sqm) of forested land and 20 pounds (9kg) of carbon dioxide equivalent. A United Nations Environment Programme report said that a global shift towards a vegan diet is vital to save the world from the worst impacts of climate change.