You're skimming over the important question: will it be ready soon enough?
Already, the answer is "probably not," and if the price of oil consumption keeps falling, the answer will pretty quickly become "definitely not."
That environment may or may not change dramatically(1), and humans and animals and plants as they exist now may not exist in the future, but I would guess that life in some form will survive, and if you define the environment to be "earth and its atmosphere," it will survive as well. It just may not have humans or animals or plants in it. Who knows.
(1) I'm not a climate scientist, but it seems like dramatic changes in our environment may well be guaranteed already. That said, I don't know for sure, so I'm being careful with my language.
What I'm saying is that it in the long run, humanity may well be doomed for the things we've put into play in the environment. That would be bad. I don't think that we'll kill off ALL living organisms. Earth will definitely survive, and I think that life on Earth will also likely survive. That life may well only be single celled organisms. Who knows.
Having said that, like you, I think that people get extremely hung up on global warming without pragmatically looking at the environmental cost will be if it keeps going for another 50 years. Warming over the last 18 years has been minimal, and if we have similar warming for another 50 years, that would provide enough time for solar to become economical and efficient without pushing the second and third world back into poverty -- because let's face it: at this point in history, limiting carbon generation also limits the productive capacity of an economy, and lowers the standard of living for everyone involved.
Yes, we might have to move our farmland a bit north, lose a bit of coastal land area, and reduce biodiversity a bit. If this is the price to save millions of human lives through better nutrition, better medical care, better transportation, better housing, etc ... then in the short term, I think we need to proceed with any far-reaching carbon regulation with extreme caution.
Right now, I think that the most pragmatic and practical thing to do is research, improve, and build out nuclear power. Unfortunately, many of the same people who are staunchly anti-combustion (I can't say 'anti-fuel', since technically radioactive material is also fuel) are also anti-nuclear. To those people, living in this world, with the primitive energy storage tech that we have today -- without a hard dose of pragmatism you'd be living in the cold and dark during a Michigan winter, and I can tell you that -10f is COLD :( (we don't get a lot of sun and wind here during this time of the year)