Latest comments posted about Time for a politics of climate change on ChinaDialogue en-gb http://www.chinadialogue.net/article/show/single/en/557-Time-for-a-politics-of-climate-change http://staging.chinadialogue.net/images/cdlogo.gif http://www.chinadialogue.net/article/show/single/en/557-Time-for-a-politics-of-climate-change A ppm (volume, ppm by volume) of CO2 approximately equivalent to 1.52 ppm (quantity, ppm by mass). The quantity in atmosphere is approximately 5.148x10^(15) ton. The calculation will be as follows: 1.52x10^(-6)x(12/44)x5.148x10^(15)=2.13GtC. Mon, 30 Jul 2007 12:37:21 -0400 http://www.chinadialogue.net/article/summary/557#comment-4111 http://www.chinadialogue.net/article/summary/557#comment-4111 Who can tell me how can the eqation that 1ppm=2.12GtC in the air be calculated? Thank you. Wed, 25 Apr 2007 03:09:16 -0400 http://www.chinadialogue.net/article/summary/557#comment-3582 http://www.chinadialogue.net/article/summary/557#comment-3582 Thanks to Tao Wang for the critique. The figure of one part per million of CO2 corresponding to about 2.1 billion tonnes of atmospheric carbon (not carbon dioxide) is taken from Socolow (2004 and 2006) who actually uses long tons (multiply by 1016.047 for a more precise conversion to metric tonnes). It would be interesting to learn more about the reason for this apparent discrepancy. I note that the IPCC figure to which you refer is referenced as 1996. Did this hold in their 2001 report, and will it still hold in their fourth assessment report (2007)? We agree that a key issue is that China needs to act now to control carbon emissions. It has been reported (New York Times, 25 Nov) that China will surpass the United States as the world’s largest emitter of carbon dioxide by 2009, a decade ahead of previous predictions. "A big reason is the explosion in the number of automobiles, but the main reason is China’s ravenous appetite for coal, the dirtiest of all the fuels used to produce electricity. Already, China uses more coal than the United States, the European Union and Japan combined. Every week to 10 days, another coal-fired power plant opens somewhere in China, with enough capacity to serve all the households in Dallas or San Diego". To emphasize again, those of us in Western countries need to act. A company called TXU has said it will build 11 new power plants in Texas use the old pulverized coal model technology, which is much dirtier than alternatives easily available in the United States, but is much more profitable. One famous and distinguished American scientist has commented that executives at TXU should immediately face trial for threatening the lives of hundreds of millions of people. But China needs to act too. We are all in a small boat together, and the boat is lying low in the water in rough seas. We should recognise who contributed most to getting us into this situation in the past, but it is in no country or people's true interest to make the situation even more dangerous than it already is, merely to benefit a few very rich people. Caspar Henderson Mon, 27 Nov 2006 10:05:02 -0500 http://www.chinadialogue.net/article/summary/557#comment-583 http://www.chinadialogue.net/article/summary/557#comment-583 "Each part per million of CO2 corresponds to about 2.1 billion tonnes of atmospheric carbon. The current level – about 380ppm – is 800 billion tonnes" This is a very suspicious estimation. In page 196 of the Stern Review, which you sited later, it says "Over the past two centuries, around 2000 Gt CO2 (Gt = billion tonnes) have been released into the atmosphere through human activities (mainly from burning fossil fuels and land-use changes). The Earth’s soils, vegetation and oceans have absorbed an estimated 60% of these emissions, leaving 800 Gt CO2 to accumulate in the atmosphere. This corresponds to an increase in the concentration of carbon dioxide in the atmosphere of 100 parts per million (ppm), thus an accumulation of around 8 Gt CO2 corresponds to a 1 ppm rise in concentration." This is big difference between these two results, yours 2.1 GT=1ppm and Stern's 8Gt CO2=1ppm. This is because the 800 billion tonnes is the human emission over the last two century, without including the carbon emission from natural process and the ambient CO2 concentration. The 800 Gt CO2 emission are responsible to the 100ppm increase in CO2 consternation, not the 380ppm CO2 concentration as a whole. This leads to different estimation of carbon emission in the future. In the same page of the Stern Review, it suggested 550 ppm CO2 would allow roughly 3700 GtCO2. After 60% absorption by vegetation, soils and the oceans, this means about 1500 Gt CO2 increase in atmosphere, which is 1500 billion tonnes, way above your 400 billion tonnes estimate. It is right to say the increased temperature will reduce the absorption of vegetation, soils and the oceans, but they will continue to absorb CO2 unless catastrophic change happens. The value given in the Stern's Review is a bit optimistic compared with the others. IPCC (1996) published the CO2 emission to different CO2 concentration. The CO2 emission value to stabilise the CO2 concentration at 550ppm was between 870 to 990 Gt CO2 and for 450ppm it was around 640 Gt CO2. The share to China according to the population is an equal and fair argument. But when we think about how much good produced in China is actually consumed by Chinese themselves, you can estimate how much carbon emission has been transferred to China's own fair share, but for others consumption and welfare. Nevertheless, China has to act more actively in controlling carbon emission now, this point is definitely right. It is not just China's duty or contribution to the world, but more importantly to give its own people a brighter future. Tao Wang Tyndall Centre for Climate Change Research and Sussex Energy Group Tue, 21 Nov 2006 17:34:18 -0500 http://www.chinadialogue.net/article/summary/557#comment-548 http://www.chinadialogue.net/article/summary/557#comment-548