It seems almost certain that the national plans will fall short of this goal, as defined and measured by the IPCC. What happens in that case is a mystery. On the other hand, if the IPCC would admit that their model projections have been disproved by the lack of any warming for the past 16 years, perhaps we could all agree that the goal of avoiding warming of two degrees centigrade has already been achieved.

The 1992 UNFCCC divided the member nations into two categories-developed and developing. The 1997 Kyoto Protocol required that the 37 developed nations undertake mandatory emissions reduction targets and timetables, while the developing nations could undertake voluntary measures and that the developed nations would help pay for these measures. The main reason the US Senate never ratified Kyoto is because China was exempted from the colossally expensive emissions cuts that Vice President Al Gore signed the US up for. 

A decade later, this is now an even bigger issue. Chinese emissions are now far above those of the US and the EU and are going to continue to rise rapidly as China builds scores of new coal-fired power plants. China's emissions have gone up so much that  per capita they are now close to the EU's. Yet China continues to insist that the developed economies as listed in 1992 bear a historical responsibility to make the emissions cuts, while China and other emerging economies, such as Brazil and South Korea, continue to develop. 

The flaw in China's position is that according to International Energy Agency projections its cumulative emissions will within a couple of decades surpass those of the EU since 1800 and those of the US soon after. The Obama administration, like the Bush administration before it, insists that the 1992 list of developed economies must be adjusted to reflect changing realities. The Chinese delegation said no at every session in Warsaw. 

But China and the US are in their different ways no longer the only obstacles to saving the planet from global warming. The Conservative government in Canada withdrew from the Kyoto Protocol in 2012. Australia's new government announced that it could not send a high-level minister to Warsaw because it would be too busy repealing the country's carbon tax. And Japan announced that as a result of closing its nuclear power plants after the Fukushima disaster, it would not be able to make the emissions reductions required by the Kyoto Protocol. It may be that Australia, Canada and Japan are blazing a path that other nations may decide to follow as it becomes apparent that the costs of a new climate agreement far outweigh the benefits.

Christiana Figueres, the highly capable and extremely well-connected Costa Rican executive secretary of the UNFCCC, challenged conference participants to keep their feet on the ground but to raise their eyes to the stars. I have given her advice some thought in the weeks since returning from Warsaw to Washington, but she has not shaken the conclusion I reached when Kyoto was negotiated in 1997: in the unlikely event that global warming turns out to be a problem, a UN treaty cannot possibly be the way to solve it.