Why live sustainably?

Why did I change my life so that I live more sustainably? Because I saw the necessity of it. I realized that if I didn't do it, I couldn't depend on anyone else to. I started becoming educated about the destructive systems we depend on for energy, like coal power and nuclear power, and decided to quit being a part of it. Of course I still have a long way to go to complete sustainability, mostly in terms of driving less and becoming food independent, but the community group I'm part of is an attempt to address that and take it to a larger scale. If we turn a blind eye to what we're doing to ourselves and the Earth, who do we expect will save us?