As I discussed in The End of Hope, I believe there is now sufficient evidence to conclude that civilization as we know it is doomed, and there's virtually nothing we can do to stop it. The analysis I did back in 2011 appears to be holding true, especially the "worst case" projections of population and Gross World Product, which for planning purposes are likely to crash during the period 2030 to 2070.
Planning for what? There is still some hope that our species, albeit a much smaller number of us, will survive. For those of us who care about optimizing the future for as many people as possible, this means that we must focus on ensuring that the survivors can have the best life possible, and that future generations won't repeat our mistakes. In short, we need to try to offset part of our legacy of death.
In the book, "The Shock Doctrine: The Rise of Disaster Capitalism," journalist Naomi Klein describes how believers in unrestricted capitalism have used (and in some cases precipitated) disasters to enable the takeover and ruination of entire countries by cutthroat corporations while their citizens were fighting to survive. As ecological disasters and resource depletion overwhelm the world, those who control the corporations will be even more tempted to acquire power beyond their dreams, even as the foundation of that power implodes around them. Because this same acquisitive drive has been a key contributor to the combination of over-consumption and pollution that is pushing us and other species to extinction, it must be vilified at every opportunity and kept from having any significant influence over whatever culture ends up surviving.
Much of the world that the survivors inherit will be indistinguishable from what we might associate with the mythical hell, and due to the persistence of greenhouse gases, those conditions will last for at least a millennium. Regions that might remain habitable will need to be mapped, and both physical and cultural tools (including knowledge) will need to be developed so they can stay that way. Where adaptation in harsher parts of the world is possible with additional technology, that technology and the means to maintain it will also need to be provided.
This effort will require a heroic level of selfless commitment by many of us who can't expect to be among the survivors. There will be a lot of resistance to be overcome, initially among those who are unaware of what's ahead or in purposeful denial about it. It is far too easy, even for us, to hide from the harsh reality of what we've created, and to ride out the remaining vestiges of the comfortable lives many of us grew up expecting to continue into a healthy old age. One way to help deal with these challenges can also inform the survivors we dedicate ourselves to helping: document what's happening around us; observe and learn about the variables affecting our local environments, manmade and natural. Get to know in person the people who will either share our plight or be among the survivors who can testify that we did our best to help them, despite what we already did to make their lives a living hell. Find others who feel the same way, because we can't do it alone.