Fig 1. Last 1000 years temperature
estimation made by Michael Mann.
Fig 1. This graph is taken from the UNEP/GRID-Arendal site
This graph is the Hockey Stick
Graph created by geophysicist Michael Mann. It is also
called MBH98 after the three author Mann, Bradley, Hughes
and from the year it was compiled 1998.
As you can see the temperature graph shows
that the temperature just varied a few tenth of a degree
before 1900. This graph was publish in the very prominent
scientific magazine Nature and made quite a sensation. It
was also prominent display in several places in the 2001 IPCC report, the UN Intergovernmental Panel on Climate Change.
It has now been removed from the latest
2007 IPCC report because it has become to much of an
embarrassment for the IPCC to include it.
The graph was subsequently criticized by
many global warming skeptics and historians, because weather events such as the Medieval Warm Period and the
Little Ice Age were absent. Although with little
imagination one can see that the temperature is a little
higher in Medieval time period and little cooler after
1500. But the variation is far to small to correspond to
historical records.
Criticism from some skeptics have been
centered around the statistical Auto Regression method
which was used and the associated computer program. It was suspected
that it might be responsible for data set end
irregularities which could be responsible for some of the
rapid rise in the 20th century.
I don't know about that, it is hard for me
to judge, but I believe the statistical method he used to
display the graph is correct and based on the collected
data.
The flaw is in the method in collecting the
various types of sampled data or proxy as it is called in
climatology circles. It turns out that the data is
collected from different sources such as corals, tree
rings, ice cores and temperature records.
The temperature is only taken from
measurements during the last century. The temperature
estimation is mainly taken from biological materials and
is primarily from tree rings. With tree ring analysis or
Dendrochronology which is its scientific name, it is
possible to evaluate the growing condition of trees. The
distance between the rings are larger if the growing season is
longer for a specific year and it becomes shorter if the
growing season is short. However the tree ring growth is
also affected by other conditions such as humidity, the
amount of sunshine, soil and by fertilization.
Because not enough reliable temperature recordings exist
before the 1900, the temperature estimations
before that time are largely based on tree ring recordings.
In order to estimate the tree ring growth correspondence
to temperature variations a
normalization was made from tree ring recordings during
the 20th century by matching them against made temperature recordings. The problem of the tree
ring recordings after 1900 are that they do not follow the
temperature changes correctly.
The condition for tree ring growth after
1900 have changed substantially.
What was missed and what cause the flaw is
something that every school kid learn at school or at
least they use to!
And that is the biological mechanism of
Photosynthesis!
The tree rings are affected by increased
levels of CO2. In other words the tree rings grow larger
today than they did 100 years ago.
A major part of the extra tree ring growth is from
elevated levels of Carbon Dioxide instead from the
expected temperature increase. Another problem is from the
so called Urban Heat effect. This effect is caused at
temperature recording stations in or near urban areas
which becomes hotter over time because of urban
sprawls. The concrete and asphalt heats up the area. A
temperature station which 100 years ago was out in the countryside may now
be in an urban area. We know that most of the recorded
warming have been in the northern hemisphere in the US,
Europe, Russia and in the Artic. Some of that recorded
warming may be caused by The Urban Heat Effect.
US temperature stations and The Urban
Heat Island Effect
The made normalization and matching from
the temperature and tree ring growth means that the
temperature signals before 1900 has been severely dampened
leaving the erroneous impression that temperatures before
1900 were very static. If you look closely at the hockey
stick graph a marked kink can be seen where the
temperature recordings are absent and where the
temperature recordings are included. This is visible
around year 1900 and is a result from the different
normalization of the tree rings.
If you look at the temperature recording
going back to 1850 at the bottom of the home page you will
see that the temperature variations are of the same
magnitude before 1900 as the are after the 1900.
You don't believe that the CO2
increase has had an affect on tree
and plant growth?
Then look at this..!!
The carbon dioxide fertilization effect.
Is Michael Mann aware of this flaw in the
graph?
Of course he is. Yet he is still defending
the hockey stick graph, despite the problem with data contamination from CO2
fertilization of tree rings
History From The Little Ice Age Is Still Visible
In Scandinavia!
Few outside of the Nordic Countries may know
this, but almost exactly 350 years ago, because of The
Little Ice Age, Sweden conquered one third of what was then the Danish heartland.
Today, this is the southern and south western part of Sweden.
Background!
In 1655 a well equipped and trained
Swedish Army invaded and occupied most parts of Poland.
Although the invasion went according to plan, they didn't
have a working plan for how to pacify and role over a
hostile
Polish population.
As a result the invaders met
increasing resistance and soon found themselves fighting a
guerilla war uprising.
Rumors of the quagmire the Swedish Army had
run into spread around Europe. This tempted Sweden's arch
enemy at that time, Denmark to declare war against Sweden
on the 1st of June 1657.
The Swedish Army, in response, then quickly abandon
Poland without losing to much face.
But instead of going home, sail over the Baltic Sea to defend their home
country, the Army marched up through Germany and invaded
the Jutland peninsula, the western most part Denmark.
Which they quickly overran and occupied.
In order to end the war, their plan were
then to invade Zealand and conquer Copenhagen the Danish
capital. But at that time they had a big problem, this was because they lacked a nearby
fleet which could help them with the transportation over
to Zealand during an invasion attempt.
However they got
unexpected help by the weather, because during the severe winter of 1657-1658 they
didn't have to make that transportation by boat, but
instead they could do this by marching over frozen waters.
So. the reason for this conquest was as a
result of a
march the Swedish Army made across The Frozen Belt
Straits, the main waterways between the Danish islands
and which was completed by The March Across the Great Belt
made between February 5th and 6th in 1658. This extensive march
over the frozen water was
only made possible by
the cold weather during The Maunder Minimum of The
Little Ice Age.
10 days later they reached the outskirts of
Copenhagen.
The Danes had expected a Swedish invasion
attempt first later in the spring and felt protected by
their strong navy. The sudden appearance of a large
Swedish army outside the gates of the capital took them
completely of guard. Instead of fighting, the Danes
panicked, asked for peace and Denmark lost its eastern
part in the following peace deal.
This March was made by an army of more than
10 000 soldiers comprising of infantry, cavalry and
artillery that marched a distance of about half that between
Dover and Calais or about 12 kilometers over frozen sea
water of ice expanses.
Of course, today if you look at this sea
strait in winter you will rarely ever see any ice floating in the water. |
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