It's Called the "Pucker Factor"

There's a powerful yet weird mix of angst and optimism building in advance of the December climate change summit in Paris.

Government types from the US to China to the EU express confidence that this year will succeed and do what every other summit has failed to do - reach an effective agreement to cut global greenhouse gas emissions to stay below the 2 degree Celsius target for man made global warming.

Non-government types mostly don't share that optimism.  Their skepticism, bordering on outright pessimism, is captured by this op-ed from Le Monde:

...Since the 1992 Earth Summit in Rio, fossil fuel consumption has gone on growing. The Green Climate Fund launched by the UN in 2011 has attracted only €10bn to date. In 2013 subsidies for fuels responsible for greenhouse gases totalled €400bn worldwide — four times the amount allocated to renewable energy sources.

Any international agreement will fail to keep global warming within 2ºC if governments insist on protecting a production system based on accumulation, pillage and waste. We can’t meet the challenge of climate change without popular involvement; but individual and local initiatives won’t be effective without global political will. If we are to agree to consume less energy and become more frugal — changing well-established habits — we need the prospect of an improved quality of life. There can be no real energy transition without economic and social change, and without proper redistribution of income, globally and nationally. India, where 300 million people have no access to electricity, reports hundreds of thousands of deaths from air pollution each year.

In the West, sobriety stands in direct opposition to austerity, which looks like a trick for bringing about a still more inequitable distribution of wealth. Reducing carbon emissions will require massive investment in housing, public transport and renewable energy — as much as was spent on rescuing the banks in 2008. Improving energy efficiency and living conditions could create jobs, make life easier and generate substantial economies for every household.

Sobriety means a new definition of wellbeing: using less resources and more labour, fewer machines and more human intelligence; taxing fuel to discourage unnecessary air travel; making sea freight more expensive to curb the worst excesses of free trade and encourage the use of shorter shipping routes; deciding not to exploit certain mineral resources.

The industrialised countries, with only a quarter of the world’s population, have run up a hefty environmental bill. Their cumulative emissions have already raised the global temperature by 0.8ºC, and will soon double that (1). Yet they refuse to set targets that take account of past emissions or do more than talk about cooperation, though that will be indispensable. It is time to give the countries of the South the funding and technologies they need to move to development based on energy sobriety. That means quality rather than quantity.
From everything I've read on both sides, the optimists and the skeptics agree on one thing.  Both see the Paris summit as our very last chance for reaching a deal that can satisfy the 2C target.

The Le Monde article is important for making the critical point that we can't win this with only some deal on cutting carbon emissions.  There's more to it than the major players - especially the United States and China - want to acknowledge; things such as overproduction, over-consumption and waste; inequality and wealth redistribution; and the issue no one on either side seems to want to touch - overpopulation.