[asa] A Response to the BBC Documentary on The Great Warming Swindle-1

Friends: In response to a query from a friend of mine about the BBC documentary
on climate, I have drafted a response covering 6 different allegations that are
made in the documentary. Since my document is quite long I am going to put my
remarks out for your review and comment in six consecutive postings to this
list. If you are not interested please just hit the delete button
ken piers

1. Ice-core analysis going back 650,000 years reveals that there is a
correlation between global warming and cooling periods and carbon dioxide
levels in the atmosphere. But the data appear to indicate that rising
temperature precedes rising atmospheric carbon dioxide levels by several
hundred years in the ice core records. Hence the claim is made that rising
temperatures cause increasing carbon dioxide levels not the other way around.
Response: It should be obvious that the warming/cooling cycles and atmospheric
carbon dioxide variations that are revealed in ice cores dating back 650K years
are not due to human activity. Neither were the warming periods likely
triggered by CO2 release to the atmosphere. And probably the warming periods
were not due, mainly, to variations in solar output. Instead the periodic
warmings and coolings over these time frames were very likely due to variations
in the earth's trajectory around the sun
http://en.wikipedia.org/wiki/Solar_variation#Milankovitch_cycle_variations

 which can cause quite significant changes in the nearest approach and tilt
angle of the earth with respect to the sun.
As the earth sinks into an ice age due to such Milankovitch cycles we expect
that atmospheric CO2 will decline due slower vegetative decay, and greater CO2
absorption in the cooling ocean water. So CO2 decline in the atmosphere follows
behind temperature decline mainly due to the very slow response of the
planet’s oceans to changing temperatures. But as the planet emerged from a
cold period, photosynthesis and decay speeds increase, and sometime later the
ocean waters warm and release some of their dissolved gases into the atmosphere
and greenhouse gases build-up in the atmosphere again - but following some time
after the beginning of the warming period. So yes CO2 levels follow the onset
of warming. But it would be expected that the atmospheric warming then was
further supported by the rising greenhouse gas levels in the atmosphere
(positive feedback cycle).
But today's situation is quite different. We are not in a Milankovitch regime
where one would expect a warming climate; in fact, the evidence suggests that
we are close to the beginning of a 11,000 year Milankovitch cycle of an
expected slow cooling trend. Moreover the time frames for Milankovitch cycles
are on a millennial not a decadal time scale so are not germane for the warming
we are observing in the past 30-40 years. And in the entire 600K year ice core
record the maximum CO2 levels in the atmosphere never rose above 280-300 ppm -
they are now above 380 ppm. The suggestion that the ice core data show that CO2
levels in the atmosphere can not cause climate warming is almost surely bogus.
For the first time in measurable and estimable history we appear to be in a
regime where rising carbon dioxide levels are leading rising temperatures. For
humans this is an unprecedented condition.

Ken Piers

"We are by nature creatures of faith, as perhaps all creatures are; we live by
counting on things that cannot be proved. As creatures of faith, we must choose
either to be religious or superstitious, to believe in things that cannot be
proved or to believe in things that can be disproved."
Wendell Berry

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Received on Wed Mar 21 11:31:47 2007