Ice Age Now
Posted by: Anonymous User ()
Date: April 12, 2007 01:21AM
Re: Ice Age Now
Posted by: Jose ()
Date: April 12, 2007 10:05AM
Hey Lois, thanks for the articles. I think they are incorrect however, since they are taking a very simplified view of the data and possible not taking unto account seasonal variations of the sea level, see [staff.acecrc.org.au].
Sea level records show variability over a wide range of dfferent time scales, including:
1. Tidal oscillations of periods which are predominantly in the approximate range 12
to 24 hours, but which also have components covering time scales of only a few
hours to years.
2. `Weather scale' phenomena, with time scales ranging from hours to weeks.
3. Seasonal variations.
4. Interannual variations such as the El Ni~no / Southern Oscillation (ENSO), which
occur (very roughly) every 4 to 6 years.
5. Changes in climate over periods of tens of years to geological times scales.
In order to estimate any climate-related trend in sea level (i.e. (5), above), other
variations are regarded as `noise' and are removed from the original data, generally
either by tidal analysis or by time-averaging. This unwanted `noise' is a serious problem
and dictates that long records are needed for the meaningful estimation of long-term sea
level change. Douglas (2001) argued that records of at least 50 to 80 years duration may
be required. Shorter records will undoubtedly yield rates of long-term sea level change
that are contaminated by unwanted noise, and it is important that any such results are
qualied with an appropriate estimate of the probable uncertainty.
Probably the most widely quoted estimates of long-term sea level change at Funafuti
have been made by Mitchell et al. (2000) and by the NTF (2002). In particular, the
NTF (2002) reported:
As at February 2002, based on the short-term sea level rise analyses, performed by the
National Tidal Facility Australia, for the nearly nine years of data return show a rate of
+0.9 mm per year.
The historical record from 1978 through 1999 indicated a sea level rise of
0.07 mm per year.
These results, which are based on quite short records and for which no uncertainty
estimates are provided, have unfortunately been quoted out of context and without
appropriate qualification. For example, the `greenhouse skeptic' website `Still Waiting for
Greenhouse' (http://www.john-daly.com/) made the statement (April, 2002) that:
Now the National Tidal Facility, based in Adelaide, Australia, has dismissed the Tuvalu
claims as unfounded. They have maintained accurate monitoring of sea level at Tuvalu.
According to their latest news release on the issue, `Sea Level in Tuvalu: Its Present
State', the NTF concludes `The historical record from 1978 through 1999 indicated a sea
level rise of 0.07 mm per year.' This compares with the IPCC 3 claim of 1 - 2.5 mm/yr
for the world as a whole, indicating the IPCC claim is based on faulty modelling.
Quite apart from the fallacy in suggesting that observations from a single site can cast
doubt on a global average value, the above statement contains no qualification
concerning the relatively short length of the record, nor of the probable uncertainty in
the estimate. The purpose of this document is to provide values for the long-term
relative sea level change4 at Funafuti, Tuvalu, with appropriate estimates of uncertainty,
using standard statistical analyses of publicly available data.
It is very easy to be intentionally confused by skeptics who are not intellectually honest. I also think some proponents of global warming are too rash, but there is a wealth of scientific evidence on which to base the arguments.
On a different note, and logically unconnected to this controversy, I object on the strongest possible terms to using the pretext of global warming as a scheme for western governments and corporations to exploit and enslave their own populations and third world and developing nations, both economically and socially. That is indeed a real danger, but does not mean global warming is "fabricated".
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