1) Lab grown meat sounds gross and I don't want to eat it, ever.
2) Did you read Oryx and Crake? If you haven't, you should. It's good.
3) We don't need artificial meat to reduce the environmental impact of the meat industry. We need to eat less meat.
Look, you probably wouldn't be reading this blog if you weren't vegetarian friend or a vegetarian ally. And I know I usually keep the crazy on the DL. And as a pro-choice person, I know that your life and my life are different and you probably love steak. But I'm gonna put this out there - you don't need steak. You certainly don't need steak every day. You could eat steak once a week and live to a ripe old age. Even if you do need meat every day, you don't need it every meal. Most people eat vegetarian for breakfast, and they turn out fine.
When it comes to health and wellbeing, meat doesn't matter. Eating a balanced, wholesome diet matters and I for one believe that scientific resources should be spent curing diseases and the problems of the world, and that if everybody around the world just ate meatless for a few meals a week, that too would substantially reduce the environmental impact of meat.