[Phys-L] Re: global warming

[dtmarx at ILSTU.EDU (David T. Marx)]

> --- "David T. Marx" <dtmarx@ILSTU.EDU> wrote:
>
> > My point on this is that how can we rely on climate
> > models to determine global temperatures 50 to
> > 100 years in the future, when we can't even predict
> > temperatures next week or next month?
>
> In the same way that it is difficult to predict the
> individual steps in a drunkard's walk problem but not
> too hard to find the overall bias in a direction.
>
> Marc "Zeke" Kossover

Marc and John both tried to make this point, but I just do not see this statistical analogy.  The
models predict large increases in temperature with increasing levels of "greenhouse gases," but
when we consider that that level has already increased by 30% over the past hundred years with
negligible at most increased global temperatures due to these gases.  The physical data, satellite
and large scale ground temperature, does not support the predictions made by these models.

Back to the physical data:
Balloon and satellite data show no temperature increases for the period 1979 to 2002.  The ground
based data do show a trend.  Here is another explanation from climatologist Douglas Hoyt (2001):

Of the 2907 stations in the [GISS] database, only 161 (or 5.5%) have complete temporal coverage
from 1900 to 1990. All but 19 of these stations are in the United States. The US, with the most
complete record anywhere, has no trend in temperatures during this century [that is, the
temperature trend is neither increasing nor decreasing with time —WHS]. In 1989 and 1990 about 30%
of the stations ceased reporting. This may account for the difference in global temperature trends
derived from surface observations when compared to balloon and satellite observations.  Support for
this idea comes from the fact that 135 stations in the USSR ceased observing at the end of 1989.
Subsequently there appeared to be a warming in the USSR but this warming is not supported by
pressure observations. Thus, it appears half or more of the reported global warming from ground
observations is arising from this change in station coverage. It is possible that as much as 0.2 C
of the 0.25 C warming for 1979-1999 can be explained by this change in stations, although more
study is required to refine this number. Other locations where the surface network has notable
problems include South Africa, Nigeria, Timbuktu, Algeria, Peru, central and coastal Brazil, the
Seychelles, Diego Garcia, New Guinea, and several Polynesian islands.