I've thought this too but then you are leaving the future to those who breed more irresponsibly. Another way to look at it would be that we have a responsibility to raise more responsible people.
Hrm, I'm thinking that all the time one spends raising a single child could be spent educating a lot more children to be responsible. Raising != educating of course, but raising individual responsible children doesn't scale the same way that education can.
I suppose the question is whether the future is a gift or a curse.
Though I agree. It's odd - I've known people who seemed offended by Idiocracy, but couldn't really come up with any flaws in its basic premise (in short, well-educated highly-productive people (for traditional values of productive which is its own debate) tend to have fewer kids, and people are usually like their parents, so over time we'll have fewer people like that).
Yes, this is true. For me the way that I deal with the reality of a planet becoming a shitty place to live is to not have children. It is the best way for me to cope with the situation. People can choose to do otherwise.
Have you considered letting your children decide whether they want to be alive on whatever the future has in store for this planet? Life is optional; they can opt out at any time. But my hunch is that they'll appreciate being alive and decide to make a go of it, however tough it is. After all, there is no alternative; the only life they can have is the one you give them.