We still need cars, but we don't need meat. And there are people working on reducing transportation and energy emissions because that is a hard problem. Buying beans instead of meat at the grocery store is not a hard problem, and one any of us can immediately do.

And if you are worried about plant matter and all the land used for it and transportation emissions around it, what do you think the major of animals eat? They are confined to sheds, not green pastures. They eat plants shipped to the farms, and they eat a hell of a lot more than humans do. Eating the animal means we take a fraction of the total calories the animal consumes. It is completely inefficient. More here: https://ourworldindata.org/food-choice-vs-eating-local

No one denies we evolved eating meat. But that is the pasted. We can do better in the future. "Tradition" is a word worth censoring.