Show us the Evidence, Penny Wong!
Dr David Evans
[A slightly shorter version of this article appeared
in The Australian newspaper on Friday 18 July 2008]
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 plays
only a minor role and is 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 hotspot
about 10 km 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 hotspot
whatsoever. Not a little hotspot, but none at all.
If there is no hotspot then an increased greenhouse effect
is not the cause of the global warming. So we now 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 hotspot is there but went undetected. Yet hundreds of radiosondes
have given the same answer, so statistically it is not possible
that they missed the hotspot. 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 hotspot. If you believe that you 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
that implicate carbon emissions as a significant cause of the
recent global warming. The world has spent $50b 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 support the idea that carbon
emissions cause global warming. Computer models and theoretical
calculations are not evidence, they are just theory.
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 last 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 report only land based data, and report 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 shows 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 four 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
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 mind 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 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 before wrecking the economy. It is the job
of our opposition politicians and press to demand the evidence
from the relevant minister, Penny Wong.
And what is going to happen over the next decade as the global
temperature continues not to rise? When the public find out that
all the above points were known in 2008, might they feel deceived,
furious at the futility of the economic sacrifices?
Who is going to be held responsible? Perhaps the political
class, for not having the wit to examine the evidence? Maybe
the press, for not have not done even the most elementary job
of informing a debate and asking questions? (If any of the missing
signature, the lack of actual evidence, the lack of temperature
rises since 2001, or the 800 year lag of CO2
in the ice cores are news to you, then no, your press has not
been keeping you well informed.)
Don't you think some evidence is required
before wrecking the economy? Someone simply has to demand to
see evidence. You will find that there is none.
Three related articles may be located here:
The Missing Greenhouse Signature, Links to Evidence and Global Warming Science Moves On
A brief biographical statement about
David Evans may be found here.