"No smoking hot spot!"
David Evans | July 18, 2008 in THE
AUSTRALIAN
I devoted six years to carbon accounting, building models
for the Australian Greenhouse Office. I am the rocket
scientist who wrote the carbon accounting model (FullCAM)
that measures Australia's compliance with the Kyoto
Protocol, in the land use change and forestry sector.
FullCAM models carbon flows in plants, mulch, debris,
soils and agricultural products, using inputs such as
climate data, plant physiology and satellite data. I've
been following the global warming debate closely for
years.
When I started that job in 1999 the evidence that carbon
emissions caused global warming seemed pretty good: CO2
is a greenhouse gas, the old ice core data, no other
suspects.The evidence was not conclusive, but why wait
until we were certain when it appeared we needed to act
quickly? Soon government and the scientific community
were working together and lots of science research jobs
were created.
We scientists had political support, the ear of
government, big budgets, and we felt fairly important and
useful (well, I did anyway). It was great. We were
working to save the planet.
But since 1999 new evidence has seriously weakened the
case that carbon emissions are the main cause of global
warming, and by 2007 the evidence was pretty conclusive
that carbon played only a minor role and was not the main
cause of the recent global warming. As Lord Keynes
famously said, "When the facts change, I change my mind.
What do you do, sir?"
There has not been a public debate about the causes of
global warming and most of the public and our decision
makers are not aware of the most basic salient facts:
1. The greenhouse signature is missing. We have been
looking and measuring for years, and cannot find it.
Each possible cause of global warming has a different
pattern of where in the planet the warming occurs first
and the most. The signature of an increased greenhouse
effect is a hot spot about 10km up in the atmosphere over
the tropics.
We have been measuring the atmosphere for decades using
radiosondes: weather balloons with thermometers that
radio back the temperature as the balloon ascends through
the atmosphere. They show no hot spot. Whatsoever.
If there is no hot spot then an increased greenhouse
effect is not the cause of global warming.
So we know for sure that carbon emissions are not a
significant cause of the global warming. If we had found
the greenhouse signature then I would be an alarmist
again.
When the signature was found to be missing in 2007 (after
the latest IPCC report), alarmists objected that maybe
the readings of the radiosonde thermometers might not be
accurate and maybe the hot spot was there but had gone
undetected. Yet hundreds of radiosondes have given the
same answer, so statistically it is not possible that
they missed the hot spot.
Recently the alarmists have suggested we ignore the
radiosonde thermometers, but instead take the radiosonde
wind measurements, apply a theory about wind shear, and
run the results through their computers to estimate the
temperatures. They then say that the results show that we
cannot rule out the presence of a hot spot. If you
believe that you'd believe anything.
2. There is no evidence to support the idea that carbon
emissions cause significant global warming. None. There
is plenty of evidence that global warming has occurred,
and theory suggests that carbon emissions should raise
temperatures (though by how much is hotly disputed) but
there are no observations by anyone that implicate carbon
emissions as a significant cause of the recent global
warming.
3. The satellites that measure the world's temperature
all say that the warming trend ended in 2001, and that
the temperature has dropped about 0.6C in the past year
(to the temperature of 1980). Land-based temperature
readings are corrupted by the "urban heat island" effect:
urban areas encroaching on thermometer stations warm the
micro-climate around the thermometer, due to vegetation
changes, concrete, cars, houses.
Satellite data is the only temperature data we can trust,
but it only goes back to 1979. NASA reports only
land-based data, and reports a modest warming trend and
recent cooling. The other three global temperature
records use a mix of satellite and land measurements, or
satellite only, and they all show no warming since 2001
and a recent cooling.
4. The new ice cores show that in the past six global
warmings over the past half a million years, the
temperature rises occurred on average 800 years before
the accompanying rise in atmospheric carbon. Which says
something important about which was cause and which was
effect.
None of these points are controversial.
The alarmist scientists agree with them, though they
would dispute their relevance.
The last point was known and past dispute by 2003, yet Al
Gore made his movie in 2005 and presented the ice cores
as the sole reason for believing that carbon emissions
cause global warming. In any other political context our
cynical and experienced press corps would surely have
called this dishonest and widely questioned the
politician's assertion.
Until now the global warming debate has merely been an
academic matter of little interest. Now that it matters,
we should debate the causes of global warming. So far
that debate has just consisted of a simple sleight of
hand: show evidence of global warming, and while the
audience is stunned at the implications, simply assert
that it is due to carbon emissions. In the minds of the
audience, the evidence that global warming has occurred
becomes conflated with the alleged cause, and the
audience hasn't noticed that the cause was merely
asserted, not proved.
If there really was any evidence that carbon emissions
caused global warming, don't you think we would have
heard all about it ad nauseam by now?
The world has spent $50 billion on global warming since
1990, and we have not found any actual evidence that
carbon emissions cause global warming. Evidence consists
of observations made by someone at some time that
supports the idea that carbon emissions cause global
warming. Computer models and theoretical calculations are
not evidence, they are just theory.
What is going to happen over the next decade as global
temperatures continue not to rise? The Labor Government
is about to deliberately wreck the economy in order to
reduce carbon emissions. If the reasons later turn out to
be bogus, the electorate is not going to re-elect a Labor
government for a long time.
When it comes to light that the carbon scare was known to
be bogus in 2008, the ALP is going to be regarded as
criminally negligent or ideologically stupid for not
having seen through it. And if the Liberals support the
general thrust of their actions, they will be seen
likewise.
The onus should be on those who want to change things to
provide evidence for why the changes are necessary. The
Australian public is eventually going to have to be told
the evidence anyway, so it might as well be told before
wrecking the economy.
Dr David
Evans was a consultant to the Australian Greenhouse
Office from 1999 to 2005.
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