Bill Gates thinks Americans' lives have to change to save the world. Here's where to start.

Bill Gates doesn't expect everyone to stop eating beef to fight climate change — though it would help. So the billionaire philanthropist is investing in plant-based alternatives in hopes that one day meat-eaters won't be able to tell the difference.

Gates, who has invested in plant-based Impossible Foods and Beyond Meat, acknowledged that it will be an uphill battle convincing meat-eaters to forgo beef, but said that the quality of meat imitations are getting better as demand grows. Some restaurants, such as Burger King, are already selling versions of their burgers using the fake beef.

"A lot of Americans will be eating burgers forever. So we need a way of making that that's not a lot more expensive and not inferior. So it's very similar to the electric car learning curve that a little bit of subsidy, a little bit of consumers driving up the volume because they care about climate, will get us to the point where I believe that green premium will also be zero, that you just won't be able to tell the difference," the Microsoft founder told "CBS Evening News" anchor and managing editor Norah O'Donnell on Tuesday.