The supposedly representative governments of the West *will not* close their borders, despite the overwhelming desire of their citizens to the contrary.
Therefore, there is only ONE step we can take: Have children. Lots of them.
Ain't democracy grand? And we want to export it all around the world!
Don't know if you were tongue in cheek but that is exactly the correct strategy. The irony is the elite want us to limit our population growth and abort all unwanteds. Guess what? Those unwanted pregnancies could very well supply us with the labor force that we don't have and fulfill our felt need to import. And the zero population movement only makes the immigration influx ten times worse.
This is just a statistical look at things with no value judgment at all. But of course I think unlimited abortion and unlimited immigration are both very bad ideas.