In this post I present the assumptions of the rate of decarbonization implicit in the emissions trajectories summarized in the graphic above (I cannot locate the full 900 page report, anyone with a link, please share!). First, here are the annual rates of emissions increases implied by the scenarios above:
I want to call attention to the figures for business-as-usual, which represents a trajectory for emissions increases assuming that no additional policies are implemented beyond those in place today. Does anyone really believe that China's emissions growth will be 3.4% per year to 2020 (much less 1.5% per year to 2050)?
Here are some facts: China's emissions grew at an average rats of 12.2% per year from 2000 to 2007 (!) (data from EIA and the figure above). If China's economy grows at a rate of 6% per year, which is less that its recent growth as well as government targets for growth of 9% to 11% per year, then the assumptions are that the Chinese economy will spontaneously decarbonize by 2.6% per year to 2020 and by 4.5% per year by 2050. If China grows at its recent historical average then the implied decarbonization of the Chiese economy is 5.6% per year to 2020 and 7.5% per year to 2050. For a point of reference, the IPCC assumes a rate of spontaneous decarbonization of about 1.5% per year, a number that we criticized as being overly optimistic in our 2008 Nature paper (PDF). And remember, I'm just talking about the BAU scenario, not those requiring actual "emissions cuts."
The assumptions of spontaneous decarbonization in the Chinese emissions paths are yet another example of "magical solutions" on climate policy. With China's emissions growing at 12.2% per year during the present decade, it is inconceivable that this rate will somehow drop to 3.4% per year to 2020, much less the 1.8% or 0.9% per year implied by the low growth scenarios.
The significance of the Chinese proposal is that it indicates that China is willing to join Europe, the United States and others in a fantasyland of climate policy detached from policy reality. It is hard to believe how that outcome leads some to greater optimism on climate policy.