OCTOBER 2ND 2011
I came across this revealing statement on page 247 of the Third Report (2001). paragraph 4.1.4. Chapter 4
"The atmospheric lifetime is truly a scale factor relating (i) constant emissions (Tg/yr) to a steady-state burden (Tg), or (ii) an emission pulse (Tg) to the time-integrated burden of that pulse (Tg-yr). The lifetime is often implicitly assumed to be constant, independent of the sources, and is likewise assumed to represent the decay time (e-fold) of a perturbation. These assumptions apply rigorously only for a gas whose local chemical lifetime is constant in space and time such as for the radioactive noble gas radon, whose lifetime is a fixed nuclear property. In such a case the mean atmospheric lifetime equals the local lifetime: the lifetime that relates global emissions to the global burden is exactly the decay time of a perturbation.
This general applicability of the atmospheric lifetime breaks down for greenhouse gases and criteria pollutants whose chemical losses vary in space and time. NOx, for instance, has a local lifetime of <1 d in the lower troposphere, but >5 d in the upper troposphere; and both times are less than the time required for vertical mixing of the troposphere. In this case emission of NOx into the upper troposphere will produce a larger atmospheric burden than the same emission into the lower troposphere. As a consequence the definition of the atmospheric lifetime of NOx is not unique and depends on the location (and season) of its emissions. The same is true for any gas whose local lifetime is variable and on average shorter than about 0.5 yr, the decay time of a north-south difference between hemispheres and one of the longer time scales for tropospheric mixing. The majority of greenhouse gases considered here have atmospheric lifetimes greater than 2 yr, much longer than tropospheric mixing times; and hence their lifetimes are not significantly altered by the location of sources within the troposphere. When lifetimes are reported for gases in Table 4.0, it is assumed that the gases are uniformly mixed throughout the troposphere. This assumption is unlikely for gases with lifetimes <1 yr, "and reported values must be viewed only as approximations." (My emphasis)
This shows why they are so concerned to fiddle the measured results of gas concentrtations to try and argue they are "well-mixed" and have no variability. So all results they don't like are suppressed as "noise", the many previous results, publicised by Beck, are suppressed, and measurements over land surfaces are forbidden. There is overwhelming evidence that none of the gases are "well-mixed", so all of the Global Warming figures are Phoney.
The Global Warming Potential of Methane used by the NZ Ministry of Environment at
puts the Global Warming Potentials (100yr basis) of Methane at 21 and N2O as 310
This appears to be based on the Third IPCC Report (2001)
However, the 2007 Fourth Report has increased the 100yr value to 25 for CH4 and reduced to 298 for N2O. (page 212 Table 2.9 chapter 2). as follows
Have they changed to the new value?
"To kill an error is as good a service as, and sometimes better than, the establishing of a new truth or fact" Charles Darwin