What would happen is everyone in the world became vegan?

Everyone would be healthier, their would be longer life age rates. AND the animals would not go into overpopulation because they are right now forced breed by the millions for food purposes, if left out of human hands there would be a normal life cycle between animals, as in animal eats animal, or animal dies of old age.

People would stop living like animals eating so much meat and only eat the right things they were supposed to eat. They would also be healthier as a result of a vegan diet. Their should be a new law requiring all of us in America to become vegan.

Instantly or gradually?

Instantly?

Not happening but if it did, we would have to deal with what to do with all the animals normally slaughtered...eventually they would die out as their aged.

Many would starve as there are not enough sources of vegan food right away. That takes time.

Don't think polution would automatically lower as vegan foods STILL have to be grown and that takes fuel to plow plant cultivate, irrigate and harvest not to mention process.

I don't think it would have the idealic outcome many think it would, at least not at first. Once many died, then there would be less population to feed so eventually the food production would come up to the demand.

Wow that would be great. If everyone would eat lots of fresh, home-grown or organic fruits and veggies, life would be much better. People would be in better moods and I think life would be more relaxed.

There would be an overpopulation of animals and the entire ecosystem of the earth would collapse, sending us into a global recession and resulting is global starvation and third-world poverty.

The upside is we will all be healthier.

Downside , many cooks, butchers, cattle breeders will go out of business.

We would be healthier, have enough food for everyone, and have more disposable income.

Everyone would live healthier for much longer.

We would have far less pollution and waste less money on health care

There would be mass rioting because people don't like to be denied bacon.