Probably the biggest obstacle that people face when trying to address environmental issues, and sustainability in general, is the sheer magnitude of the problems. We have billions of people, trillions of dollars and countless quantities of time and energy that are invested in the status quo and the continuance of unsustainability. The powers of those people and corporations are much greater than you as an individual; a sense of hopelessness is not surprising. Furthermore, the timescales over which the issues have developed, and over which they may be resolved, are enormous compared to the length of human lives. It may take several decades for any change to be realised, culturally and ecologically. This is also bound to generate a sense of hopelessness. At the same time, there is a limit to our comprehension of our actions - we may not know how harmful the effects of what we are doing are. But also, we do things in the present that we know are bad, for our health, and for the health of ecosystems in the future. We have a tendency to say, "I'll deal with it later," or, "I know this is bad (for me or for the environment). Whatever." Eating unhealthily is a wonderful example of this. Access and availability of good food aside, many people know that such eating is bad for them, in general, yet satisfaction now supersedes degraded health later - diabetes, cancer, obesity, etc. Maybe we don't want those future ill effects to affect us, but out of habit we accept the ill effects and live in a state of fear knowing that the day will come that bad diagnoses loom.
It is really hard to imagine what the future is going to be like - Will our efforts pay off? Who will be the next President? When will the next oil spill happen? Which will be the next fish species to go extinct because of overfishing? How might we be able to deal with the fear of living in such a state, knowing that we are degrading what it is that sustains us, but are so invested in the way it is that we kick the stone down the road? Rather than think and worry about the future, we can all make decisions here and now such that tomorrow will be a good day. We all want to live in a world in which what we cherish is alive, healthy and sustained. To live in that world, we must act in such a way that we cherish, respect and sustain now, today. It is not complicated. If I respect the tree or the river today, it will be healthy and full of life and love tomorrow. If I respect and cherish my relationship with my friends and family today, those relationships will grow stronger and more resilient; tomorrow those people will still love me, and I will still love them. I do not have to live in the fear of a grudge or a toxic conversation. Now is easier to comprehend and experience and think about. Acting well now will save us much trouble tomorrow.