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  • UN environment (IPCC) study

    1. mans effect on environment decreased by 25%; their guesstimates were too high.



    UN downgrades man's impact on the climate

    Richard Gray, Science Correspondent, Sunday Telegraph
    Last Updated: 1:32am GMT 10/12/2006

    Mankind has had less effect on global warming than previously supposed, a United Nations report on climate change will claim next year.

    The UN Intergovernmental Panel on Climate Change says there can be little doubt that humans are responsible for warming the planet, but the organisation has reduced its overall estimate of this effect by 25 per cent.
    >
    The IPCC has been forced to halve its predictions for sea-level rise by 2100, one of the key threats from climate change. It says improved data have reduced the upper estimate from 34 in to 17 in.

    It also says that the overall human effect on global warming since the industrial revolution is less than had been thought, due to the unexpected levels of cooling caused by aerosol sprays, which reflect heat from the sun.
    >
    2. cow farts contribute more to warming than cars, planes trains together, generating 18% of greenhouse gasses.


    Cow 'emissions' more damaging to planet than CO2 from cars.

    By Geoffrey Lean, Environment Editor
    Published: 10 December 2006

    Meet the world's top destroyer of the environment. It is not the car, or the plane,or even George Bush: it is the cow.

    A United Nations report has identified the world's rapidly growing herds of cattle as the greatest threat to the climate, forests and wildlife. And they are blamed for a host of other environmental crimes, from acid rain to the introduction of alien species, from producing deserts to creating dead zones in the oceans, from poisoning rivers and drinking water to destroying coral reefs.

    The 400-page report by the Food and Agricultural Organisation, entitled Livestock's Long Shadow, also surveys the damage done by sheep, chickens, pigs and goats. But in almost every case, the world's 1.5 billion cattle are most to blame. Livestock are responsible for 18 per cent of the greenhouse gases that cause global warming, more than cars, planes and all other forms of transport put together.
    These things are starting to read like government economic reports; eternally revised complete with excuses why they were wrong and warnings that some day they'll come close
    Last edited by Dr Mordrid; 10 December 2006, 17:17.
    Dr. Mordrid
    ----------------------------
    An elephant is a mouse built to government specifications.

    I carry a gun because I can't throw a rock 1,250 fps

  • #2
    Dunno why you put such store in misquotes and misunderstandings from popular newspapers, especially the Telegraph.

    I have some 1995 figures for CH4 emissions (I'll quote the means, but there is a possible range)
    Natural wetlands 115 Tg
    Rice paddies 110 Tg
    Enteric fermentation of all mammals 80 Tg
    NG exploitation 45 Tg
    Biomass burning 40 Tg
    Termites 40 Tg
    Landfills 40 Tg
    Total c 530 Tg
    Source: Tetlow-Smith 1995

    In 1995, the proportion of radiative forcing (ie the effect of GHGs) due to gases was:
    CO2 56%
    CH4 11%
    CFCs 24%
    Stratospheric H2O 4%
    N2O 6%
    (Source: Barry et al., 1998)

    It is therefore clear that the effect of mammalian emissions (including all the wild herbivores in Africa) in 1995 was about 80/530 x 0.11 x 100 = 1.66% of the total radiative forcing. Let's assume that half of this was due to domestic cattle, and I think this is a very generous assumption, made even more so by rounding up to 0.9%.

    Now we know that the global cattle farming has been increasing by an average of 7% p.a., so that in 11 years, assuming everything else remains the same, this means that the figure has increased by 2.1 times, so we are talking about 1.9% of the total at the most.

    The total CO2 represents 56%, of which 28% is due to burning fossil fuels, so that the total due to this represents 0.56 x 0.28 x 100 = 15.7%, of which over half is used by transport, say 8%. This is over 4 times higher than the proportion due to enteric fermentation within cattle.

    Sorry! I simply do not believe these figures.

    As for the first report, the writer clearly knows nothing about what he is trying to interpret. Just take his last sentence: how do aerosol sprays reflect heat from the sun? I suppose he thinks NASA are shooting the cans up into orbit?

    What he is trying to say is that aerosols (nothing to do with sprays) in the upper atmosphere reduce the radiation reaching the earth's surface. Only particle sizes in the range 0.1 - 1.0 µm are effective for this. In this range, smoke from forest fires is the largest contributor, followed by urban particles and continental background. The particle sizes from volcanoes, dust storms, sand storms and sea salt are all much larger than 1 µm and settle out or rain out too rapidly to be significant.

    These aerosols have been taken into account in the past. I understand that the major new influence may be the major increase in forest fires (man-made in the Amazon, Indonesia, possibly California and Australia etc.) some of which may be due to or exacerbated by warmer temperatures drying out the tinder and (for natural fires) increased lightning activity. This has now been taken into the mathematical modelling.

    As for sea level rises, the 1992 IPCC predictions revised the most probable sea level rise down from 66 cm to 49 cm (26 to 19.3") with best estimate limits of 38 cm to 55 cm. The 86 cm figure quoted was a worst case uncertainty scenario where all the variable parameters added together, with a fractile probability of 0.01. It is typical of rubbishy pseudo-scientific journalism to quote this. What is happening is not a significant lowering of estimates but that increasing knowledge of all the variables and better modelling is narrowing the probability range. In reality, I understand the most probable sea level rise has been lowered from 49 to 43 cm with best estimate limits much tighter, under reserve that I have not yet got a copy of the 2007 report.

    I HATE journalists who write about things they have no knowledge of !!!
    Brian (the devil incarnate)

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