This
series of pages is being written in response to what I see as a global
crisis. For years now we have been assailed by TV, newspapers, and
politicians with a loud and very clear message - "Planet Earth is
getting warmer and man's activities are responsible!" We are
further told that "There is a global consensus among scientists
that man-made carbon dioxide is the primary cause of global
warming."
I
am so unhappy with these statements, and by the bad science which is
being demonstrated by all those "scientists" who are supposed
to have contributed to the "global consensus" that I felt I
had write something, to try to stop the misinformed and biased political
train before it wrecks itself in the station, with all of us on board.
These
pages will examine the facts. Not just the facts which
conveniently fit and support the model of runaway temperature rises,
claimed to be caused by the CO2 produced by mankind, but all the other facts which
point in a very different direction and which are being ignored by the
global warming "disciples" simply because they do not fit the
theory. I should stress that I am not a climatologist, nor am I an
oceanographer, but I know a number of people who are, and I read their
work. I also like to think I can see something if it is staring me
in the face, and when we speak about global warming I feel frankly that
most people have become so blinded by the "hype" that they
can't see the truth. I am a scientist, I am a reasonable astro-photographer, I have a good understanding of most
things astronomical - and recently I have made an intensive study of all
the current science associated with the climate changes which are
clearly taking place on planet Earth. So here, presented in the
clearest way I can, are all the factors which we know are
influencing our climate, to help you make your own judgement about
what's happening, and to decide for yourself whether you, like me, feel
we are being deceived.
Is
Global Warming Happening?
Before we start it is important to
establish whether the major claim of the "warmists" is
correct. Is the planet actually warming up?
Well,
the answer based on all available data is "yes -
but". The "but" is that, as I will show in a
moment, the Earth's climate has always been subject to cycles of warming and cooling,
so we should not be too surprised to learn that the average temperature
varies all the time, whatever we do in our 4x4's or with our smoky
chimneys. In fact, in the current episode, global
warming began long before the "Industrial Revolution".
It actually began 18,000 years ago as the earth started warming
its way out of the Pleistocene Ice Age, a time when much of North
America, Europe, and Asia lay buried beneath great sheets of glacial
ice. And this is one of the most important messages I want to
communicate to you, so I will repeat - Earth's climate is constantly
changing and cycling from cold to warm and back again. Our climate
has been dominated by ice ages and glaciers for the past several million
years and we are currently enjoying a temporary reprieve from the deep
freeze.
This
is because approximately every 100,000 years Earth's climate warms up
temporarily. These warmer intervals, called interglacial periods,
appear to last approximately 15,000 to 20,000 years before we go back to
a cold, ice age climate. We are currently standing at year 18,000
in the current inter-glacial period, and so we have to believe that our
current respite from the ice is much nearer its end than its beginning.
"Global
warming" during Earth's current interglacial warm period has
greatly altered our environment and the distribution and diversity of
all life. For example:
-
Approximately
15,000 years ago the earth had warmed sufficiently to halt the
advance of glaciers, and sea levels worldwide began to rise.
-
By
8,000 years ago the land bridge across the Bering Strait was
drowned, cutting off the migration of men and animals to North
America.
-
Since
the end of the last Ice Age, Earth's temperature has risen
approximately 16 degrees F (9 degrees C) and sea
levels have risen a total of 300 feet (100 metres)! Forests have
returned where once there was only ice.
I
don't intend in this article to go deeply into the ways we can measure
historic and prehistoric temperatures. I will only summarise it
here by saying that by using a mixture of oxygen isotope ratios, temperature
sensitive tree ring data, ice core data and numerous other sources it is
possible to calculate pretty accurately what the various data looked
like way into the distant past. I am not saying the methods used
are foolproof, but I, and most scientists around today are satisfied that there is sufficient scientific
basis and peer review confidence that we can be pretty sure
the data are good.
So
how exactly has global temperature varied with time?
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This
is a plot of global temperature variation for the last 1,000
years. You can see that there is a fairly definite cycle -
of about 500 years - and the well documented Medieval Warm
Period is easy to see, as is the "Little Ice Age"
between about 1350AD and 1850AD, when
again there is extensive documentation of a period of lower than
average temperatures. The point is our current "warm"
interval is normal, and could have been predicted using these
data.
Historical temperature and
carbon dioxide data referenced from R. S. Bradley and J. A. Eddy,
based on J. T. Houghton et al., Climate Change: The IPCC
Assessment, Cambridge University Press, Cambridge, 1990 and
published in EarthQuest, vol 5, no 1, 1991. |
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If
we go back even further in time things get really interesting
because we can see evidence of yet more cycles - much longer
this time, with a period of perhaps 4,500 years. For the
current debate about man-made global warming, the period known
as the Holocene Maximum should be examined, because it
was the hottest period in human history. However, this period
occurred approximately 7500 to 4000 years before the present
day, long before
humans invented industrial pollution. Early man was
powerless to change things then, and I would submit we are
powerless to change things now. |
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