Yes, it's too late... too late for human "civilization," if that's what it is. The twin demons of climate change and Peak Oil will do in the dominant human societies within the next 50 to 75 years. Several billion people will die prematurely within the 21st Century, and replacement rates will plummet as well. Agricultural zones will shift northward and diminish, as fuel supplies to transport dwindling food to the remaining population become scarcer and more dear. Ironically, as industrial activity declines, particulates in the atmosphere will settle out, resulting in increasing atmospheric warming. Average global temperature will probably rise 8 degrees centigrade by 2100.
Human societies will be reduced to isolated pockets of agrarian communities in areas still able to support limited local agriculture, probably in Canada and Alaska, here in North America. I suspect the coast will still be habitable to a limited extent, depending on how much is left after the die-off. The problem now is the huge population here, leading to unforeseeable social consequences.
It's never too late for the non-human world, which will change, of course, and it will thrive, as it always has. Some species will go, some will increase, new species will begin in the new conditions. It'll be an interesting time biologically for those humans interested enough to observe and record.
Freedom and democracy? It will return and live as it did before modern technocratic society drove it underground. Probably something like Ed's vision of free and semi-autonomous agrarian communities, living in harmony with natural cycles, based on local production for local consumption, democratic decision-making and mutual aid. Those who attempt to cling to the old competitive, divisive, oppressive ways will die. Cooperation will rule the day, as it did for thousands of years before.
What can be done? Nothing. The die is cast. The dominant society, the US capitalist, technocratic, industrial society, cannot change fast enough to meet this rapidly approaching challenge. Most humans are incapable of changing their lives enough to make a difference. All politicians are locked into a system predicated on perpetual economic growth. We cannot solve the problems of this society with the tools available in this society.
Climate change is rolling along swiftly in an accelerating, self-reinforcing cycle that will not reach equilibrium until human technological output is reduced to near zero. Even then, it may take a century or more to settle into the new pattern that emerges. Even if tomorrow everyone in the United States were to adopt the lifestyle that Jean an I now enjoy, it would be too late. The system is in motion, the clock is running.
All that is left now is to prepare for the inevitable, become the Irish monks in the monasteries of the British Isles, hoard the knowledge through the Dark Ages, keep a small population of aware humans alive until conditions settle down again. Humans will survive and adjust over time, in small colonies outside the edges of the ruined and abandoned cities.
I'm too old to be much affected by the coming changes, though I'll see the beginnings. It's you and your children that must do something now to prepare the way. Get the hell out of the south. Find a place up north, in the northern Rockies, where you can grow food, raise animals, manage water, raise your children in the new world. Their children will inherit a totally different word than the one you know now.
More importantly, we must teach the children a new ethic, a new world view, a new cosmology, a new Way. Those who live through the coming Cleansing must be equipped to build a world that avoids the mistakes of this world. They'll have an advantage over us, in that most of the oil wand coal will be gone, they'll be lots of raw materials for gleaning in the dead cities, and they'll be forced to live with the Earth for a long time before reaching critical population numbers.
We have a lot of work to do!