Guest essay by Eric Worrall
China’s estimated total CO2 emissions to date may have to be revised down by 15%, according a study published in Nature, because the coal China is burning is much higher quality than previous calculations assumed.
The abstract of the paper;
Nearly three-quarters of the growth in global carbon emissions from the burning of fossil fuels and cement production between 2010 and 2012 occurred in China. Yet estimates of Chinese emissions remain subject to large uncertainty; inventories of China’s total fossil fuel carbon emissions in 2008 differ by 0.3 gigatonnes of carbon, or 15 per cent. The primary sources of this uncertainty are conflicting estimates of energy consumption and emission factors, the latter being uncertain because of very few actual measurements representative of the mix of Chinese fuels. Here we re-evaluate China’s carbon emissions using updated and harmonized energy consumption and clinker production data and two new and comprehensive sets of measured emission factors for Chinese coal. We find that total energy consumption in China was 10 per cent higher in 2000–2012 than the value reported by China’s national statistics, that emission factors for Chinese coal are on average 40 per cent lower than the default values recommended by the Intergovernmental Panel on Climate Change, and that emissions from China’s cement production are 45 per cent less than recent estimates. Altogether, our revised estimate of China’s CO2 emissions from fossil fuel combustion and cement production is 2.49 gigatonnes of carbon (2 standard deviations = ±7.3 per cent) in 2013, which is 14 per cent lower than the emissions reported by other prominent inventories. Over the full period 2000 to 2013, our revised estimates are 2.9 gigatonnes of carbon less than previous estimates of China’s cumulative carbon emissions. Our findings suggest that overestimation of China’s emissions in 2000–2013 may be larger than China’s estimated total forest sink in 1990–2007 (2.66 gigatonnes of carbon) or China’s land carbon sink in 2000–2009 (2.6 gigatonnes of carbon).
Unfortunately the full study is paywalled, but it would be intriguing to know how much of that “improved” quality estimate is due to the 500 million tons per annum of high quality coal, which Australia exports to China every year, and the millions of tons of high quality coal exported to Asia every year by other producers, such as the USA.
Perhaps greens should be encouraging the USA and Australia to export more coal to China, to help China hold down its CO2 emissions, while China works to replace its annual 2.49 gigatonnes of CO2 emissions, with clean energy from wind turbines.