I'm not a climate change denialist, but I am a climate change optimist. I think it would be possible to cap things off at two degrees, but we would have to start sucking CO2 out of the atmosphere and doing something with it (like big tanks or put it underground as dry ice, etc). Anyone that thinks we can stop this by producing less CO2 is deluded. We're well beyond the "unmitigated disaster for our current environment" ppm level. If we can't fix this, at least life will evolve and move on after we and many other species go extinct due to human activity.