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Submitted by Anonymous on
Dear Michael, Your point is well taken that atmospheric CO2 (parts per million) causes temperature increase. The following graphic shows an increase in atmospheric CO2 parts per million for 1960-2000 of 50. It is a simple linear function and one can therefore use simple extrapolation to estimate a figure for the increase in atmospheric CO2 parts per million of 125 per 100 years. Taking a current value of 390 CO2 ppm for 2010 and taking 1760 as the base year for the pre-industrial initial state of CO2 ppm =280, one might thus estimate cumulative atmospheric CO2 as follows: 1760 280 ppm approx. 1960 340 ppm approx. 2010 390 ppm approx. 2060 450 ppm approx. 2110 515 ppm approx. 2145 560 ppm approx. Compare these figures with what the UK government says: “The rate of growth in atmospheric CO2 concentration depends on future fossil fuel usage, and on the ability of the biosphere to absorb CO2. The IPCC SRES scenarios used for UKCP09 all predict emissions of CO2 to increase during the first half of the 21st century, while the land carbon cycle is expected to become less efficient at absorbing CO2 as the climate warms. Consequently, the rate of CO2 build up in the atmosphere over the next 50 years is projected to be higher than in the recent past. There is still substantial uncertainty in the strength of feedbacks between climate and the carbon cycle that determine CO2 uptake, so the UKCP09 projections sample a range of land carbon cycles consistent with current understanding. For the SRES A1B scenario the projected median value for mean atmospheric CO2 concentration for the period 2050-2070 is 600 ppmV. The projected 10-90% range for this period is 520-650 ppmV with A1B forcing. More detailed analysis will be presented in future publications from the Met Office Hadley Centre.” You will note that there is a difference of 150 CO2 ppm between the Hadley centre prediction for atmospheric CO2 and one given above that is based on historical extrapolation of a trend. The UK government and many others have a policy of switching to a low carbon economy. However, the actual advice they get from their own advisers is: 1.The direct effect of burning fossil fuel on atmospheric CO2 is quite small, about 25%-30%. 2.There are many causes of increased atmospheric CO2 that have nothing to do with burning fossil fuel. An increase in solar activity or cutting down a large amount of rain forest could cause increase atmospheric CO2. The science is highly uncertain. 3. There are also causes of temperature increase, other than atmospheric CO2, such as methane, water vapour etc. The science is highly uncertain. 4. Increasing quantities of atmospheric CO2 have a diminishing temperature/greenhouse effect. Therefore, future economic growth is less polluting than past economic growth. So one can establish the “saturation” level of atmospheric CO2 p.p.m. at which carbon use is pollution-free. On this point see: "...This means that a doubling of CO2 from a different value (say, from the present value or from 560 ppm) gives the same forcing as a doubling from 280 ppm. But the response of the climate system, of course, could differ somewhat for different initial states, which is why “doubling from 280 ppm” should be included in any exact definition..." Stefan Ramhstorf, member of IPCC. The basic historical model of the CO2 greenhouse effect is that, starting from the initial pre-industrial level of 280 p.p.m. of atmospheric CO2, a doubling from 280 ppm to 560 ppm has a temperature effect of 3c +/- 1. Leaving aside other factors such as the methane effect, aerosols and claims about water vapour and applying this greenhouse effect for CO2 to the above “historical” estimates of future levels of atmospheric CO2, one can make the following estimates of future temperature increase, based on CO2 emissions alone: For: the period 2010-2060 (390 ppm to 450 ppm) = 60 increase in CO2 ppm At 3c (per doubling of CO2):= 0.64 deg.cent increase. At 4c (per doubling of CO2):= 0.857 deg.cent increase. These values are below the range of the Hadley estimates. If CO2 were the major cause of global warming, the 2c temperature increase that is proposed by the Hadley Centre would require a CO2 ppm increase in the order of 210 ppm over 50 years. This is only possible if non-fossil fuel effects and feedbacks account for 2/3 of the increase in CO2 ppm. It is not fossil fuel and future economic development per se that causes temperature increase. The problem of fossil fuels is not nearly as serious as institutions such as the World Bank suggest. In this context see the recent post: "Is temperature increase good for the planet?" Such posts are merely intended as polemic to ensure a proper balanced debate. Best Regards,ANONYMOUS P.S. I was fascinated by your remarks about Venus. In terms of geo-engineering, could one make it habitable by pumping the Venus atmosphere full of Oxygen? "We also know that the surface of Venus is very hot, and not because it is closer to the Sun—the reason instead is that the atmosphere of Venus has a lot of carbon dioxide, and this large amount traps the solar radiation that is not reflected to space and makes the surface scorching hot (because of its bright clouds—which is why we can see it--Venus absorbs less solar radiation per square meter than the Earth)." M.MacCracken