The reason Copenhagen failed is that the leaders of many nations appear to have grasped the fact that the Copenhagen benchmarks are tantamount to an economic suicide pact. Even among Copenhagen's supporters, there is not a hint of hope that drastically cutting our carbon production today will do more than drop the planet's average temperature by one to two degrees. And yet for this tiny gain, the nations of the world are expected to hobble their energy production and manufacturing sectors and return our per capita carbon output to roughly 1875 levels.
Even assuming that anthropogenic global warming has a solid foundation in hard science (definitely arguable) I have yet to see any liberal/global warming activist make a cogent case as to why a planet that is two degrees warmer in 2110 is worse than a planet that is two degrees cooler at that time. After all, Earth was warmer in the Middle Ages than it is now, and that warm period was a boon to humanity. Farmlands opened up where the weather was formerly too prohibitive. More open waterways allowed for greater commerce, etc. Likewise, a warmer planet in 2100 would likely be a net gain. Tell me, Al Gore, apart from disproven doomsday scenarios, why does this "problem" need solving, particularly at the cost of trillions of dollars in the middle of a worldwide recession?
Instead of pouring trillions of dollars into a dubious problem with even more dubious solutions, why not take a large percentage of these funds and (a) prepare for the negative consequences of global warming, and (b) positively affect the lives of those very people global warmists insist will be endangered by a warmer planet. Instead of spending trillions to take carbon out of the air, why not spend billions to develop heat-resistant, drought-resistant crops? Why not spend billions to dig a freshwater well for each needy village in sub-Saharan Africa? Surely this is a better, and more humane, use of our funds, with the added benefits of concrete, visible gains (as opposed to ephemeral "results" found only in computer models that shove contested data through questionable assumptions).
The failure of Copenhagen was a victory for common sense economics, particularly when one considers that the solutions to any climate crisis are much more likely to come from a vibrant, wealthy economy than a depleted, static one. Hopefully common sense will yet prevail in Germany and Mexico City in the coming months, and humanity can be about the business of improving life for all people, no matter what the ever-changing, always-variable climate may bring.