It's the massive overpopulation of humans that is damaging the Earth. Without that, we would not have the multitude of problems that I will briefly describe as species extinctions, resource depletions, energy shortages, and environmental degradations/pollution.
The habitat will further degrade as long as humans reproduce without constraints. Then the die-off will begin. Although I do not personally believe in AGW, if it were only real, I would welcome it as a means of reducing the human overshoot population before the other problems I mention do so. Because humans can and will adapt to climate change. However they cannot survive some of those other problems.