NZCLIMATE TRUTH 41
3RD MARCH 2004
Jim Hansen of the Goddard Institute of Space Studies in
New York, has the reputation of having started the greenhouse scare by his
testimony before the US Senate on June 23rd 1988 when he presented results
which purported to show that the surface of the earth was warming. He had
assembled temperature data from meteorological measurement stations and
shown that the "mean temperature anomaly", the deviation from a ten-year
average, was increasing in a rather irregular fashion. He assumed that the
cause was an increase of greenhouse gases emitted by humans.
This proposition has become accepted as gospel, despite
many questions that should be asked.
Hansen's results applied only to the land surface
of the earth, 29% of the total. Although there were many temperature measurements
by ships of the sea surface, Hansen, for many years, regarded
them as so unreliable that he felt unable to use them to calculate a truly
global temperature change.
The land-based measurements themselves were biased
since they were mostly made close to cities where population, buildings
and vehicle usage provided an upwards trend. There were very few measurements
in unpopulated areas.
In 1985 a paper by Folland and Parker proposed a method
for using sea surface temperature measurements which was taken up by Phil
Jones of the University of East Anglia in Britain to provide a mean global
surface temperature anomaly graph. This graph is the basis of the claim
for global surface warming of the Intergovernmental Panel on Climate Change
(IPCC). Hansen and his US colleagues have never accepted the validity of
this method. Instead they have derived a combined sea surface temperature
set based on a combination of satellite data and the ship measurements.
Despite this, Hansen and his fellow US compilers are largely ignored by
the IPCC .
Hansen has now published a major article for the "Scientific
American", March 2004, Volume 290, pages 40-49. A longer version of the
article is available from http://www.sciam.com/on
the web A claimed 14.75 MB seems to reduce to 333KB
if you are registered, but a similar article has been published at
From the title "Defusing the Global Warming Time
Bomb" he would appear to be expressing 100% support for the IPCC. However,
there are several aspects of the article which question IPCC attitudes,
but all too diffidently, and others where he contradicts himself.
"the world has begun to warm at a rate predicted by climate
Now this is simply not true. The models have so many adjustable
parameters that they can be fitted to Hansen's temperature anomalies by
fudging, but the models have no record of successful prediction. Indeed,
Hansen agrees with me when he categorises the IPCC projections as "pessimistic"
and presumes to substitute his own, more realistic projections. Of course,
ALL of the IPCC projections are not only pessimistic, but deliberately exaggerated,
and they always were. He makes a comment. " It remains to be
proved whether the smaller observed growth rates are a fluke, soon to return
to IPCC rates, or are a meaningful difference"
In talking about efforts which need to be made to reduce
greenhouse emissions he, predictably, does not dare mention the most effective
method for reducing methane emissions; a continuation of the current trend
to drain wetlands..
He quotes a common objection to his temperature record:
"The surface warming is mainly urban 'heat island' effects
near weather stations"
His answer to this objection is
"Not so. As predicted, the greatest warming is found in
remote regions such as central Asia and Alaska. The largest areas of surface
warming are over the ocean, far from urban locations. (see maps at www.giss.nasa.gov/data/update/gistemp)"
To try and argue that Russian or Alaska weather stations
are free from heat islands because they are assumed to apply to vast unpopulated
areas is simply not valid.
The suggestion that sea surface temperatures are more reliable
than land-based results is the complete opposite of what Hansen has been
saying in the past, and to suggest that the sea surface temperatures are
higher than those of the land is a lie, as I have pointed out in my Climate
Truth Newsletter No 39. The mean global temperature rise (according to NOAA/NCDC)
over the oceans (71% of the earth's surface) from 1975 to 2000 was only
about 0.4°C, whereas the rise over land (29% of the earth's surface)
was double, about 0.8°C.This is evidence of upwards bias in the land
measurements. still express amazement that they still try to compare the
Northern Hemisphere with the Southern Hemisphere when the actual contrast
is between land-based and sea-based measurements.
Hansen still quotes the land+sea measurements (biased by
the land component) for his estimate of the global temperature rise.
If he quoted only the sea surface rise he could not be quite so confident
of the "reality" of global warming, and its inability to be explained by
natural climate factors.
Of course, the sea surface temperature measurements have
an upwards bias as well. If they were corrected we might end up with a temperature
record for the surface which is similar to that shown in the lower troposphere by
the satellites and weather balloons, a record which is quite capable of
being explained by natural causes, of which the most recent have been El
Niño effects, creating a temporary upwards trend.
Fred Singer has suggested that the MSU satellites
actually do show a difference between land-based and sea-based temperatures,
so I have been on to their website at
where you can get the MSU trace for any
rectangular area on a world map.
MSU results are extremely variable over
time, and the 1998 El Niño makes assessment of any trend difficult.
Variability is much greater over land than over the sea. Anyway, I could
find no evidence that temperature rises over land between 1975 and 2000 were
any different from those over the oceans, both being approximately zero.
The only region that seems to have increased in temperature over the period
was the Arctic.
I have then compared the two maps which
purport to show regional temperature changes over the same period;
that published by Jones (Journal of Climate 2003 Vol 16, pages 206-221)
which I attached to my NZClimate Truth Newsletter No 39, and that published
by Hansen ( Journal of Geophysical Research 2001 Vol 106 pages 23,947-23,963).
which I can let you have if anyone wishes it.
For two maps supposed to be similar they
could not be more different. The Jones map, which I have given you, identifies
the few regions (only 19%) for which the claimed temperature rises are statistically
significant. They include Western Europe, North Africa. the North Atlantic,
Brazil and parts of China. Central Siberia and Alaska are given in
yellow (below 0.25°C rise per decade). The Arctic does not figure.
Hansen's map gives Central Siberia and Alaska
as the largest rises (2-7.5°C per decade) and the Arctic is 1-1.5°C
per decade.Both maps, but fairly low figures for Western Europe and North
Atlantic. Both, however, show low figures for the oceans. Jones
has negative figures for Central and South East Pacific, South Atlantic
and South Indian. Hansen has slight positive figures for these areas.
His only negative area is a small region in the Northern Pac
Pacific and the Antarctic.
As soon as you get into regional figures
you find that the whole system collapses. The surface measurements are unbelievable
and our only choice is the MSU.
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