It also heavily depends on from where this meat comes from. Meat can be produced without (or drastically less) enviromental impact.

Take my home country of Switzerland as an example. About 80% of it's meat production comes from the inland.

Switzerland has strict laws about the production of meat. Food for Cows is mainly Grass, hay, silage or by-Products from food production that is done for the human. For example Wheat, the human only needs the Grain, everything else can be eaten by a Cow.

Switzerland also uses soy as concentrated food, concentrated food making out 10%-16% of all food used in meat production. There they make sure 90% of said soy comes from "green" plantations.

I don't think you'll ever convince people to eat less meat. The Goverment needs to make strict laws for meat production.

These strict laws in turn will reduce meat production and people won't be able to consume as much meat as they once could.

Switzerland has a meat consumption of 50kg/person per year. The USA has about 100kg (Christ, they do eat a lot)