We'll probably survive far into the future, barring any major catastrophe, like a meteor impact or a super virus or nuclear war. Human beings are great at adapting to the environment and we are so numerous that it would take a SERIOUS calamity to kill all 6.8(or so) billion of us.
Not to spark too much of a "global warming debate" here, but I do not think global warming will kill off humanity. I do think global warming is occuring. The fact is that CO2 IS A GREENHOUSE GAS - it traps in heat! Do this experiment - take two glass boxes. Fill one with normal air and fill the other with more CO2 - guess which one heats up faster!? That is a CHEMICAL fact, and we've released billions of tonnes of the stuff into the atmosphere, not to mention methane and other gases which are effective at trapping heat within the atmosphere.
But will it mean the end of our species? Surely not. The threat of global warming, although real, will take decades upon decades or even a century to manifest. Human beings are slow to change but they will once things get too bad. Not only that, the eventual effects of global warming cannot be determined - it's impossible to simulate what the effects global warming will have one hundred years from now.
Our technology creates problems. But it also creates solutions. Right now, we are developing cleaner technology, more efficient circuits and learning more and more about the world. Global warming and other human follies will hurt us, will hurt the planet, but we'll survive. Maybe not comfortably, but we'll survive nonetheless.
About the only thing that can kill us at this point is a meteor the size of Manhattan. Yes we are suffering from over-population, but that can be solved, and if we don't solve it, believe me the problem will solve itself (hint: it involves a lot of people dying due to starvation).
I have no fears about the future of our species, at least for the next 300 years or so. What I do fear is the destruction of our society. The species will survive. Our way of life might not. I foresee very grim times ahead for humanity. Not mad-max by any means, more like a future as seen in "Code 46" if you've seen that film by Michael Winterbottom.