We need to begin by acknowledging that our problem has no precedent.
It appears that polite and reasonable pursuit of a transition to sustainability has failed in the face of a sort of twisted unnatural malice accidentally written into law. We are at the mercy of a tyranny of the "fiduciary responsibilities" of the officers of the large corporations that have made the miracle of modern life possible and are increasingly making the doom of the future ever more enormous and inevitable.
These blind and monstrous corporate "responsibilities" dominate the life of the advanced countries and they (and their odd echoes in China) influence many other countries.
The conventional modern view of the world has it that while economic freedoms cross all borders, all other freedoms are contingent, local, tied to geography, that is, tied to a particular nation-state and a particular sovereignty. Thus, we have international governance for trade, but not for, say, immigration, or for that matter, for freedom or for preservation of our environment.
Persons who inhabit the "wrong" nation-state are accorded limited and contingent rights. In America's incredible legal tangle, these rights as accorded to any individual may be entirely self-contradictory as well as capricious: until recently "illegal" immigrants who are now in danger of expulsion for a traffic stop were encouraged to get drivers' licenses and bank accounts and even home mortgages!
So, if there is any future to the world, the homebodies who haven't seen much of it are overrepresented in making the necessary decisions! And it is the political "responsibility" of their elected representatives to maintain an environment favorable to their own nation in competition with all others, as well as responsive to the aforesaid "fiduciarily responsible" corporate monsters.
Looking at the CO2 picture in particular, (and other global issues may have similar features) the trouble is that there may be no solution that can possibly satisfy the major players (The G7, the BRICS, southeast Asia) individually that can actually resolve the problem that the trillion-and-first ton of carbon is probably going to be emitted, and then some.
It's little wonder when you think about it. In round numbers there are 7 billion of us and we have 450 billion tons left to allocate among us. That leaves you and your half share of all your descendants 65 tons of carbon to play with, or 240 tons of CO2.
Now the US has been holding pretty steady at 19 tons per capita. That means if 1) you don't want to cross the trillionth ton boundary (close to the 2 degrees C line) and 2) you are American and 3) you don't want to use more than your fair share and 4) you don't want to change anything until the last minute, you will have to go cold turkey on carbon emissions in twelve years. No car, no electricity, no heating fuel, no imported food, nothing. Your share of what's left of the atmospheric sink will be used up at that point.
Will the world hold us to this? No, they won't. The world is as addicted to American excess as America is. The whole crazy system is currently based on the Chinese lending us the money we paid them to buy stuff they made for us that we don't need so they can afford to build stuff for themselves that they don't need. Somehow if we do this, there is food on the table, and if we don't, there ain't. To those who believe in the Invisible Hand, this must be reasonable because it is happening.
I am beginning to suspect are past the point where we can rely on our governments to fix this situation.
Certainly the corporations won't help.
The Breakthrough Institute keeps telling us to hold our collective breaths for a deus ex machina solution, but it's getting mightly late for our savior to arrive in the form of, say, a safe, scalable backyard nuclear plant or a sunlight to algae to oil process. Don't get me wrong. I'm all for the quick fix if it's there to be had, but we really are talking about an enormous scale. I'm reminded of the avatar in the Douglas Adams' Restaurant at the End of the World, who arrived to late to save anything at all.
Getting back to governments, it begins to look as though the COP cannot work. Governments are beholden to too many interests to behave as sane participants in a shared effort. Everyone is thrilled to let the Chinese and the Yanks share the blame for business continuing as usual. Perhaps our successors will be wiser than we are, but time is very definitely running out.
My modest suggestion is that we work toward a global consensus among the populations of all the countries, and not among the diplomats; further, that allocations will be designated at the individual, not the national level, and that all resulting rules will apply to individuals.
So, suppose each person alive today gets an allocation of 65 tons, and is free to sell it on the open market. That way, poor people who are carbon frugal get an income source, and rich people get to keep using carbon-based energy for a while as the cost goes up. Most of the buyers will presumably be industrial...
I can see several problems with this approach but it has some advantages 1) simple 2) arguably fair 3) market based 4) enforces a strong cap. It would also light a fire under private sector research into carbon free alternatives a lot better than a few DoE grants would.