03/18/2010 05:12 am ET Updated May 25, 2011

How Good Is China's Offer for Copenhagen?

The Chinese government has laid down its initial marker for Copenhagen: China would commit to reduce the carbon intensity of its economy (tons of carbon dioxide emitted per unit of economic activity) 40 to 45 percent by 2020. That's progress at a rate of 4 percent a year, which sounds impressive -- but how much of a problem is the fact that it's carbon intensity that the Chinese are committing to reduce?

Measuring the national commitments in Copenhagen is not simple. Most of the parties involved are busy spinning to make themselves look better. There are actually four important facets each nation's commitment:

1) Total tons of carbon emitted. Globally, this is what matters to the climate. Scientists agree that the current world-emissions level -- 28 billion tons -- needs to peak by 2020 and then decline rapidly. 

2) Tons of carbon emitted per capita. This number needs to come down from the present 4 tons to 2 tons per capita no later than mid-century, and if we want to be reasonably safe, much sooner. Since the only reasonable basis for allocating the world's carbon sinks, the capacity of ecosystems to absorb carbon, is per capita, per capita emissions are the most appropriate measure of whether a country is worsening the climate problem or helping to solve it.

3) Carbon intensity -- Tons of carbon/unit of economic production. This number is mainly of interest to the citizens of a country. It indicates how good a job the country's economy is doing of producing economic value for the carbon being emitted. Countries whose carbon intensity is coming down fastest are positioning themselves better to compete in a carbon-constrained world.

4) Domestic reductions vs. international offsets. The U.S. and Europe plan to meet many of their carbon-reduction goals by paying for projects in other countries. While the Kyoto protocol permits this, in the long term it's problematic, because once ALL countries have to start reducing their carbon emissions, we need both reductions of emissions in the first world and tropical forest protection in the third world. We really can't afford to view them as "offsetting" each other as if we had the luxury of choosing one or the other. So a given carbon commitment met through offsets is simply less ambitious than one met through domestic actions.

Obviously, the first three measures are linked: If you know future population and future gross domestic product (GDP), you can calculate total carbon emissions from either of the other measures. Total tons of carbon emitted = population x per capita emissions = GDP x carbon intensity.

So how does the Chinese commitment stack up?

In 2006, China emitted 6.1 billion tons of CO2 or 4.5 tons per person. China emitted 1.4 tons of carbon dioxide for every $1,000 of gross domestic product.

By contrast, the U.S. emitted 6 billion tons of CO2 (19 tons per person) but only .52 tons of CO2 per $1,000 of GDP.

Globally, the average was 4 tons per person and .7 tons per $1,000 GDP.

So while China and the U.S. are having an equal total impact on the climate, and both are emitting more carbon dioxide per capita than the climate can tolerate, the average inhabitant of China emitted less than one fourth as much CO2 as the average American. At the same time, the U.S. squeezed almost six times as much economic value out of a ton of CO2 -- and China got less economic benefit from a ton of carbon than any significant nation except its former communist-bloc allies.

Let's assume that over the next decade China grows at 8 percent a year and that it decreases its carbon intensity by 4 percent a year. China's per capita income would then more than double, from $6,000 to $12,000. By 2020 China, would be emitting about 9 billion tons of CO2, its per capita emissions would have risen to 6.5 tons, and its carbon intensity would still be very high -- it would need 4.3 tons of CO2 to generate $1,000 of GDP.

Currently the European Union emits only 7.8 tons CO2 per capita, so China wold be emitting per capita carbon at the same level as Europe today, and more tons of carbon in 2020 than the EU's commitment for Copenhagen. China is already part of the problem (CO2 emissions greater than 2 tons) and will, as a practical matter, have become a carbon polluter at the same per capita level as Europe.

This is clearly not adequate. But it's complicated by the composition of the Chinese economy. Two factors drive energy intensity -- efficiency and the relative role of manufacturing, mining, or fossil fuel production in an economy. These three activities emit the most CO2 -- and China's role as the world's manufacturing center means that its economy emits far more CO2 than, say, India's. One third of Chinese emissions, for example, come from making cement alone.

But the problem isn't energy intensity per se as a measure -- it's the number. Suppose China committed to a 3 percent increase in the efficiency of its energy sector, increased the share of its energy that comes from renewables by 3 percent a year, and shifted from its present reliance on heavy manufacturing for export to consumer fabrication for domestic consumption at a rate that reduces its energy intensity by 2 percent. China could then, while still growing at 8 percent a year, double its per capita income without increasing its carbon emissions at all.

But, the Chinese will say, why should commit to something as ambitious as that when we look at what the U.S. is offering? With expected growth in GDP of 3 percent a year, the U.S. is putting on the table an offer of 17 percent reduction in carbon emissions. Even if all of this took place domestically, with no international offsets, we are committing to reduce our energy intensity by only 3.6 percent a year -- which is pathetic, lower even than the Chinese commitment. Note that from 1996 to 2006 U.S. energy intensity decreased from .66 ton per $1,000 GDP to .52 -- a decline of 2 percent a year, at a time when the federal government was doing nothing to encourage the trend. And we are saying that much of our reductions for the next ten years will come from international offsets.

The answer to the Chinese from the rest of the world should be that the Americans are actually going to do much more than they promise, and you have everything to gain from getting more bang for your carbon bucks. So let's up your number so we can all put some serious peer pressure on the U.S. -- which remains the real underperformer on the global climate stage.