On the surface, it appears that humans are doomed as the blue planet spins in distress of environment degradation. Hard constraints on lifespan would make every human selfish and local utility maximizing. But grandparents appear to care for generations just starting off (1) even though they are unlikely to derive any personal benefits from it. It is a paradox and just the hardware desire to spread genes does not seem to explain it properly.
Perhaps there is a sliver of hope for sustainability. Errors in evolution may have introduced irrational thoughts into the human psyche, resulting in some caring for future generations. Such thoughts may provide a force behind sustainability and that is substantially more powerful than what activists can bring to the cause. The very idea that a human will care about a future in which she doesn’t exist is difficult to imagine but then the thought may give one satisfaction and fulfillment, sans the politicians.
Sustainability is a complex concept. For nearly a million years, humans did not have to worry about it. Then in the last hundred years, as they started exhausting life giving Oxygen in their limited greenhouse, things changed. As smog enveloped Delhi, Shanghai, Mexico city and even San Francisco, and rivers receded while oceans rose, it became increasingly clear that future could be different. Some worried about their children and grandchildren but then realized that they may have to worry about themselves.
As the politicians start wars, commit crimes, execute enemies and cater to religion, there is little hope for sustainability.