Spread fear and despair to everyone you're connected to.
Yes, we need to move rationally and carefully, but we're only going to do that when a tipping point of people start believing this is an existential threat akin to an incoming asteroid that they or their children will be destroyed by.
This is what's driving increasing movements like the Green New Deal. The closer we get to the impact, the more people notice, start freaking out, and demand action. The faster we can make the majority panic and demand change, the more likely we'll have time to do something effective.
Realistically though, it's probably already too late to save our civilization.
Vegetarianism could be fine if it's only with crops grown locally with not a whole lot of transportation involved, but that's not likely to happen anytime soon. Not to mention individuals have very little impact on the actual problem.
Even if we grant that this is all we need to do (I don't believe it is), you can't honestly be suggesting that 8 billion people are going to wake up this year and decide to voluntarily sacrifice such a primal desire.
Without big acts of legislation, this will only become reality when lab grown meat becomes significantly cheaper and available. That could be decades away, which is too late.
