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The UK government has a policy of switching to a low carbon economy. SUMMARY AND INTRODUCTION. 1.The direct effect of burning fossil fuel on atmospheric CO2 is quite small, about 25%-35%. 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. The government is in a position to question its own policy, if it chooses to do so. DETAILED ANALYSIS OF UK ADVICE. Hadley predictions: CO2 parts per million. The UK government (Hadley Centre) has announced temperature predictions for 2010-2060 based on 12 different climate models. They state that their central estimate for temperature increase over 50 years (2010-2060) is 2 deg.cent. The figure applies to the entire UK area and is essentially a global estimate or at least a northern hemisphere effect. The Hadley centre states that the land carbon cycle is expected to become less efficient at absorbing CO2 as the climate warms and that this area of science has substantial uncertainty. Here is an e-mail from the centre in which they accept that it is not so much increasing industrial emissions of CO2 but the ability of the biosphere to absorb CO2 that will account for increased C02 ppm in future: "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." Enquiries Officer UK Climate Impacts Programme School of Geography and Environment. When one takes a closer look at the predictions, one sees that it is difficult to account for an increase of this magnitude in terms of CO2 emissions alone. The Hadley estimates for 2010-2060 appear to be based on uncertain theoretical models and computer predictions about secondary greenhouse effects other than CO2 such as methane, aerosol pollutants and water vapour etc. Society is being asked to make reductions in carbon usage, even though fossil fuel itself is not necessarily the actual culprit. It is important to keep the public well informed about all the alleged causes of global warming. The following graphic http://www.ipcc.ch/graphics/graphics/syr/fig2-3.jpg 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. (These atmospheric CO2 figures will be used later to estimate temperature increases. See below. N.B. There is not complete consistency in these numbers due to different estimating rules). These estimates of future cumulative CO2 emissions for the period 2010-2145 are essentially calculations about the path of future economic growth, particularly in China and India, that would have been provided to the Hadley Centre (Met.Office) by an outside source. By contrast, the Hadley centre predicts that CO2 ppm increase for 2010- 2060 will be up from the current level of 390 ppm to 600 CO2 ppm in 2060, far more than suggested above. Can CO2 ppm really grow more than 210 in 50 years? This is only possible if non-fossil fuel feedbacks, such as methane and falls in aerosol pollution, deforestation etc. account for 2/3 of the increase in CO2 ppm. According to the centre most of the increase in CO2 ppm is thus due to changes in the ability of the biosphere to absorb CO2 as the climate warms (i.e. feedbacks). Although the Hadley Centre claims that future CO2 ppm increase is not simply linear, reality shows that carbon intensivity per unit of GDP is falling naturally in USA and EU. Russia, an example par excellence of an old smoke-stack economy, is the country with the highest carbon intensivity per unit of GDP in the world. It is doubly difficult to see how atmospheric CO2 alone could account for a 2c. increase over the next 50 years in view of the following fact: "...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. In other words, the marginal rate of CO2 temperature effect is falling. Increased quantities of CO2 emission have a diminishing greenhouse effect. Therefore, future economic growth is less polluting than past economic growth. Increased levels of atmospheric CO2 will have a very diminished temperature effect beyond 560 p.p.m. So one must establish the saturation level of atmospheric CO2 p.p.m. at which the temperature effect becomes negligible. This is the level at which carbon use is pollution-free. And specifically, in the range where we are today, a doubling of CO2 from the current level of 390 ppm to 780 ppm would have temperature effect of 3c.+/-1. Hadley predictions: Temperature Increases. 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 estimates of future levels of atmospheric CO2, one can make the following alternative 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 140 ppm over 50 years. This is scarcely a probable estimate on the basis of likely future economic development. And: from 2010 to 2145 (390 ppm to 560 ppm) = 170 increase in CO2 ppm. At 3c (per doubling of CO2):= 1.82 deg.cent increase. At 4c (per doubling of CO2):= 2.428 deg.cent increase. For convenience one may use 1760 as a base year for the start of industrial activity and subsequent human influence on the atmosphere. My understanding is that human activity caused 1c. temperature increase over 1760-1960 and a further 0.5c. increase over 1960-2010. The rate of temperature increase in the period 1960-2010 was thus already 2 times greater than the rate for 1760-1960. The Hadley centre now predicts a further 2c. temperature increase making a total increase of 3.5c. for the period 1760-2060. The UK government is suggesting that CO2 ppm increase for 2010- 2060 will be up from the current level of 390 ppm to well in excess of 600 CO2 ppm. Can CO2 ppm really grow more than 210 in 50 years? This is only possible if non-fossil fuel effects and feedbacks account for 2/3 of the increase in CO2 ppm.