Does the Chinese emissions 'error' matter? By John Barker

Recent analyses that China’s carbon dioxide (CO₂) emissions might be 1.2 gigatonnes or 20 per cent higher than previously estimated have generated something of a feeding frenzy in the media; and not just the daily tabloids. Even The Scientific American has jumped on the bandwagon, adding a few more factoids to increase the alarm.

It is understandable that we could be alarmed by a figure of 1.2 gigatonnes; that’s a mighty big figure. It’s equivalent to the total of Japan’s annual emissions, the Sydney Morning Herald repeated, without providing the more useful fact for its readers that it is also about three times all of Australia’s annual emissions.

It reminds me of the caption of a famous Punch cartoon, after it was announced that the postwar census of elephants in Burma suggested that many thousands were missing: “are you sure you’ve looked everywhere?”.

Three questions come quickly to mind: Is it true? If so, why? If so, so what?

First, is it true? The original Nature article is an impressively detailed analysis, which finds the discrepancy between the aggregate (national) Chinese emissions and that of the 30 provinces. According to Guan et al, energy accounting is poor in China, particularly in the myriad of small enterprises in the provinces.

Very few people would be in a position to corroborate the analysis; however, Professor Wang Yi, director of the Climate Change Research Centre of the Chinese Academy of Sciences in Beijing has immediately counter-claimed that the official figures may be overstated by 10 to 20 per cent. He claims that the authors of the Nature article have not taken into account the differing calorific content of the different grades of coal used across China.

This is understandable; the energy content of coal can vary from less than 10MJ/kg for wet brown coal (lignite) to almost 40 MJ/kg for dry, clean anthracite. Australians are very familiar with this situation when Victorian coal is compared with Queensland coal. China is a mix of all of these types. So a familiar situation is emerging; dispute between experts in the light of inadequate data.

Even if the Guan analysis is correct, does it matter? It does, to the extent that if emissions abatement is attempted in China via a carbon tax, then the figures would be skewed and there would be free-riders. But this is no different to Australia, where the Gillard government is only going to tax the top 500 (or so) carbon emitters. The whole abatement business is very approximate, so a 10 to 20 per cent error is not significant.

On a global scale, the “error” of 1.2 GT or 20 per cent of China’s emissions is not as impressive as the media announcements make it out to be. China emits about 24 per cent of the global total, so even taking the top end estimate of a 20 per cent “error”, China would be emitting about 28 per cent of the total; that is, another 4 per cent of the global total. In perspective, China’s emissions are increasing at an annual rate similar to this; possibly 5 to 8 per cent. So the “error” amounts to an adjustment of perhaps several years; meaning China is emitting at a rate now that we thought that they would be emitting perhaps two years hence.

So what is the fuss about? Certainly, accurate data is always desirable, but does it change anything? China is leading the world in most areas of renewable energy manufacture and is rapidly increasing its domestic use. Its energy intensity is dropping dramatically.

I suspect that the media attention paid to the Guan et al paper is partly justified; we need to get the numbers right. But it is also partly due to what I see is a persistent inclination by the media to portray China and its achievements as lacking credibility. For example; China announces its quarterly economic outcomes quicker than the ABS and each quarter our pundits disparage their data, only to find year-on-year the data is as good as ours (is the ABS disparaged for its quarterly revisions?).

But as always, as soon as the buzz-words of “gigatonnes” and “Chinese error” are splashed across the media, the caravan moves on, leaving The Conversation to try to make some sense from it all.

John ED Barker, is an adjunct professor at Murdoch University.

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