I think this is an ultimate question that needs immediate action to follow, except it seems most populations aren't keen to make the changes required to create a stable and sustainable future. It's the old "we say we care because it's easy to say we care, but do we really act like we care?" scenario.
Perhaps we can each concentrate on ourselves more. Question what it is we are doing that can make a difference, even if the difference is subtle. After all, pennies in a jar accumulate. I had a teacher who went on vacation using only the pennies she'd accumulated during a single year.
Once we accept the lifestyle changes we need to make in order to impact the environment less, then all we need to do is change the game plan. Some say this is simpler said than done. I wonder if it isn't just a matter of not wanting to change because of comfort zones and the prospect of "giving up" aspects of habit or tradition people are accustomed to telling themselves they cannot live without.
For example, there are things I like for various reasons, many of the reasons being sensory: taste, touch, smell, tactile...etc. I can claim they bring me pleasure and I feel I must do them. But can I learn to reject them and find them unpleasant once I fully accept that they cause more harm than good in the environment, that they may even cause pain and suffering that I do not witness first-hand?
Yes, I know I can change my own mind and reroute my senses to something more positive that is whole and more sustainable. I find this is total pleasure and not blind pleasure.