Why I am an Anthropogenic Global Warming Sceptic: Michael Hammer
Posted by Michael Hammer, September 21st, 2009 - under Opinion.
Tags: Climate & Climate Change, Philosophy
I HAVE been asked several times ‘why am I so sceptical of the anthropogenic global
warming (AGW) hypothesis’? There are many reasons, some of which I have documented
in previous articles at this weblog, but these have relied on sometimes complex calculations
which I admit can be difficult to appreciate. So I would like to outline here a
few of my reasons based only on simple consistency with the AGW proponents’ own data.
1. The AGW movement claims there has been a global temperature rise of 0.5C over
the last 60 years and that this is due to increasing CO2. Both AGW proponents and
sceptics accept that the relationship between energy retained and CO2 concentration
is logarithmic (a constant increase in retained energy for each doubling of CO2).
The AGW movement data also shows that since 1900 CO2 has risen by very close to
half a doubling over this 60 year period.
IPCC have claimed in their 4th assessment report (summary for policy makers), that
the most likely temperature rise by 2070, when CO2 will have risen by a further half
doubling to twice the level in 1900, is a further 3C rise (page 12). Why would
the first half doubling give 0.5C rise while the second half doubling gives 3C or
6 times as much rise?
2. One claim I have heard is that it takes the climate a long time to respond to
the change in CO2 concentration and we have not yet seen the entire rise from the
first half doubling. The same IPCC 4th assessment report (page 12, 13 and 14) indicates
that if CO2 were stabilised at the current level, the temperature would rise by a
further 0.2C over 2 decades stabilising at 0.7C above the 1900 level.
If the current temperature rise is not yet at the equilibrium level then for the
business as usual scenario the temperature rise by 2070 will also not be at the equilibrium
level. Yet the IPCC data suggests the equilibrium rise from the first half doubling
is not even one quarter of the less than equilibrium rise from the second half doubling.
To me this is illogical.
3. IPCC claim an increase in retained energy of around 3.7 watts/sqM for each doubling
of CO2 (1.66 watts/sqM for the current rise page 4). They admit this is much too
small to result in a 3+ degree temperature rise. The large temperature rise is based
on claims of very large net positive feedback in the climate system.
Yet, every natural stable system I can think of exhibits net negative feedback. Indeed
the terms stability and negative feedback are synonymous since negative feedback
is what causes stability. By contrast, positive feedback causes instability (such
as tipping points where a large change in output occurs for a small change in input).
Stability does not mean zero change, it means the response to changes in input
are small enough and sufficiently controlled so as to not cause system destruction
or runaway. If you want to argue that the climate system is not stable then I would
why it has remained conducive to continued life on this planet for billions of years.
This is despite all the change in CO2 levels, volcanic eruptions, changes in solar
output and orbital changes over the millennia. To me, that is a very good definition
of climate stability.
4. The AGW modellers claim cloud feedback is positive. AGW advocates seem to divide
clouds into two categories, low clouds and high clouds. Every report I have read
acknowledges that low clouds cause cooling. With regard to high clouds there is
some dispute but the AGW modellers claim they cause warming. Further they claim
a warming planet results in a bias away from low clouds and towards high clouds thus
exacerbating warming, hence contributing to positive feedback.
At the same time they claim constant relative humidity in their models. This means
that as the temperature rises, more water must be evaporating. Now unless we want
to predict that the amount of water in the atmosphere is going to continuously rise
until the oceans are suspended over our heads, more evaporation must imply more precipitation
ie: more rain. However, rain only comes from low clouds not high clouds, so more
rain means more low cloud mass not less low cloud mass. This contradicts the previous
position. If the claim is that both increase, then that means significantly more
cloud mass in total. Clouds are the biggest contributor to Earth’s albedo (the fraction
of incoming solar energy reflected back out to space). Rising total cloudiness means
increasing albedo and the albedo is very strongly cooling. The albedo already causes
100 watts/sqM to be reflected away from Earth. To cancel out the entire impact claimed
by IPCC for doubling CO2 only requires an increase in cloudiness from 60% to 62.4%.
An increase in temperature, leading to more evaporation, in turn leading to more
cloudiness which reduces the solar input to Earth thus reducing temperatures is a
description of negative feedback not positive feedback.
5. The claimed “proof” of positive feedback is a model prediction of a hot spot
in the tropics at mid troposphere levels. However all the experimental evidence
from many, many measurements has failed to find any evidence of such a hot spot.
In science, a clear prediction that is falsified experimentally means the underlying
hypothesis on which the prediction is based is wrong.
6. The reports documenting man’s CO2 emission use some scarily large numbers but
these have to be viewed in the light of the overall system size. For example, a
million dollars is an extremely large amount of money for a private individual but
it is almost petty cash for a government. If we want to put the numbers into perspective
we need to relate them to the size of the system. Why not express CO2 quantities
in terms of how many PPM 1 year’s emissions will raise or lower the atmospheric CO2
level (if all of it stayed in the atmosphere). We could call that PPM equivalents.
In those terms, human emissions amount to about 2.7 PPM equivalents. Now NASA have
published a diagram showing annual CO2 transfers for the planet. This shows terrestrial
plants absorbing about 61 PPM equivalents. We know that both rising CO2 and rising
temperature favour faster plant growth. That’s why horticulturalists artificially
raise CO2 levels in glass houses to about 1000 PPM. It is also why plants grow faster
in the tropics than in cooler locations on earth. More to the point, a recent study
showed average plant growth has accelerated by about 6% over the last 30 years. A
6% increase in plant growth means a 6% increase in absorbed CO2, from 61PPM equivalents
to 64.7 PPM equivalents. This means that human emissions have increased by 2.7 PPM
equivalents but plants have increased their absorption by an extra 3.7 PPM equivalents
over the same period. The increased plant growth is consuming more than 100% of
human emissions. Is there another (natural) factor contributing to CO2 increases?
This response, more CO2 leading to faster plant growth which in turn consumes more
CO2 is another example of the widespread bias towards negative feedback I alluded
to earlier. Apart from which, is increased plant growth and thus agricultural productivity
bad? I would have thought it was highly desirable.
7. The AGW hypothesis is based on temperature rises between about 1975 and 1998
or about 25 years worth of data. This is claimed to be definitive yet the last 10
years worth of data shows falling global temperatures. This is claimed to be a short
term aberration and of no consequence. I do not see how 25 years can be considered
definitive beyond dispute while 10 years of data is a short term aberration, too
short to be significant. I would have thought at least a 10:1 ratio would be necessary
to make such a claim.
8. If I adopt this 10:1 ratio by looking at the last 100 years worth of data I find
1910-1940 temperatures rising while CO2 was not. 1940 to 1975 temperatures falling
while CO2 rising, 1975 to 1998 temperatures rising while CO2 rising and 1998 to 2009
temperatures falling while CO2 rising. Three quarters of the period shows no correlation
or negative correlation with CO2 and only one quarter shows positive correlation.
I do not understand how one can claim a hypothesis proven when ¾ of the data set
disagrees with it. To me it is the clearest proof that the hypothesis is wrong.
9. For the last 10 years the global temperature data shows either no atmospheric
temperature rise or indeed a falling global temperature. Recently this has been
claimed to be due to a combination of a quiet sun and changes in ocean circulation
superimposed on the underlying warming trend. The further claim is that when these
effects reverse, warming will start again with a vengeance.
If these natural processes can cancel out the impact of AGW then they are as powerful
as AGW. If they can overwhelm the impact of AGW to cause cooling they are more powerful,
yet IPCC and other AGW proponents have claimed in previous assessment reports that
solar influences are only a minor contributor compared to CO2.
The sun was unusually active during the latter half of the 20th century in contrast
to its current inactivity and the ocean circulation was the opposite of what is now
happening. Thus the natural effects claimed to be causing cooling now would have
been causing warming in the late 20th century. If these natural effects are as large
as the AGW impact then they would have caused half the observed 20th century warming.
If the natural effects now outweigh the AGW impact to cause cooling then they would
have been responsible for more than half the observed 20th century warming.
This is not only in contradiction of the earlier IPCC claims, it also means that
the actual impact of CO2 increases since 1900 is much less than the claimed 0.5C.
At most 0.25C and possibly much less even than that.
If in fact the temperature returns to the long term average over the next few years
(as seems to be increasingly likely), it suggests that these natural processes were
responsible for essentially all the observed temperature changes over the 20th century
with negligible impact from CO2 changes.
10. I have looked at the raw temperature record for the USA (USHCN data) and the
Bureau of Meteorology data for Victoria, Australia. Both show fluctuations of temperature
with time but zero underlying trend for the last century. By contrast, the official
IPCC endorsed data shows a strong underlying upwards trend. When I investigate why
the difference, I find that the raw data has been adjusted for several supposed factors
and every one of these adjustments created a warming trend. This implies that the
claimed warming trend is due to the adjustments, not the raw data. In any less controversial
scientific issue, such a result would be viewed with the greatest possible scepticism
and would be extremely unlikely to be accepted.
When I examine the raw temperature data record for cities compared with nearby suburban
or rural areas, I find an extremely high signature of urban heat island effect.
Yet the people doing the temperature adjustments claim that urban heat island effects
are negligible and do not require correction. This is despite the fact that a significant
proportion of the measurement stations are in cities.
Such a clear factor not corrected for while other more subtle claimed factors are
corrected casts further doubt on the correction protocol. If there is an upwards
bias in the corrections, it means the claimed warming trend is exaggerated and may
in fact not exist at all.
11. The mainstream media keep reporting that the current situation is increasingly
dire and is much worse than even the previous pessimistic projections. When I examine
this statement I find that previous projections predicted rapid atmospheric warming
during the last 10 years whereas in fact we have had cooling. They predicted rapid
increase in rate of rise of sea level when in fact the rate of sea level rise has
recently declined. They predicted a very rapid increase in Arctic summer sea ice
loss whereas in fact, for the last 2 years, it has been increasing. They predicted
a rapid rise in hurricane incidence and severity when in fact there has been a decline.
To me the media’s many claims are not supportable. I also consider it to be beyond
simple error. At best it is unpardonable gross carelessness in checking the data
they are reporting and at worst it is deliberate bias in reporting.
12. More recently, in response to the data showing no warming for the last 10 years,
I have seen new claims that global land temperatures are now deemed irrelevant. The
newly discovered measure of importance is the rise in ocean temperature, since it
is now claimed that this is by far the largest planetary heat sink. If that claim
is true, it makes all the previous data claiming to show strong global warming over
the period 1975 to 1998 also irrelevant. To suggest that from 1975 to 1998, the
energy went into warming the land and air and then abruptly in 1998 it stopped doing
that and the heat instead went into heating the oceans is, to me, completely absurd.
Nature simply does not work that way. It is like claiming you put the kettle on,
for the first minute the energy goes into heating the water and then abruptly it
stops heating the water and starts heating the room instead.
13. Looking further at the claim of warming ocean temperatures. Late last century
it was realised that the method of measuring ocean temperatures was extremely inaccurate
and unreliable. To overcome that, a sophisticated, global system of buoys was designed
and implemented at very considerable cost and effort. These buoys repeatedly dive
down to measure temperatures and then resurface to report back findings This network
is called the Argo network and it became operational in 2003. Since becoming operational,
it has shown ocean cooling. Yet the scientists who claim ongoing ocean warming exclude
the Argo data and the satellite data instead relying entirely on the earlier poor
The same scientific community which claimed a method was inaccurate and unreliable,
designed and implemented a new high accuracy measurement system, are now rejecting
the new high accuracy data in favour of the older data they themselves viewed as
unreliable. How can that be justified? Why is the data from the older less reliable
method correct, while results from the new, high accuracy methodology are wrong?
What does that say about the scientists who designed the Argo system but apparently
don’t trust its output? To me it suggests selecting data to prove a favoured hypothesis,
commonly called cherry picking.
Some sites are talking about “correcting” the Argo data. Why should a carefully
thought out, brand new, high accuracy system already require adjustment to its outputs?
Was a mistake made in the design? Why are the proposed adjustments again in the
direction of exacerbating the claimed warming? When the raw data contradicts the
hypothesis yet the “adjustments and corrections” all reverse that result so as to
support the championed hypothesis, it’s time to start worrying.
14. What mankind is doing by consuming fossil fuels is recycling CO2 that used to
be in the atmosphere but got trapped in the distant past. Is there a “correct” level
of CO2? What I have read suggests that the Earth was a more verdant place before
the CO2 got locked up in fossil fuels. Would the Earth be more or less pleasant
a place if the carbon currently locked up in fossil fuels were again available to
the biosphere. Not just for humans but for all living things, plants and animals.
Surely we should consider that before we pick some arbitrary recent point in time
and declare that the CO2 level at that time is the ideal to be maintained at all
FROM a slightly different but related perspective, I see the AGW story continuously
changing. When one measure no longer trends the wanted way, a change is made to
a new measure (change from surface to ocean temperatures and ocean acidity). In
one report, an effect is claimed to be negligible when that suits the hypothesis
yet the same measure is later used as a reason to explain away embarrassing trends
(Solar influence and ocean currents). All the observed effects are very moderate
(less than 0.5C) if present at all yet hysteria is generated on the basis of hypothesised
extreme future outcomes (up to 6C rise and 10 meter sea level rises). Outcomes far
enough in the future so as to be un-testable yet close enough to impact people being
born today. Claims based on abstract models that fail even short term validation
tests. As a practicing scientist, I have seen this scenario more than once before,
changing benchmarks and indicative parameters, rewriting predictions and predicted
causes after the event, excusing erroneous predictions. These are clear signs of
propping up a false hypothesis.
There does seem to be clear evidence that temperature changed several times over
the 20th century both up and down. There is far less evidence for any underlying
upwards trend due to CO2 and many reasons to question the data analysis that tries
to demonstrate such a trend.
One of the arguments I often hear is “well even if AGW is not absolutely proven we
should take action just in case its correct” – the precautionary principle. I see
two reasons to disagree with that.
Firstly, if rising CO2 should bring about some warming it is by no means certain
that this would be catastrophically bad or for that matter whether it would be bad
at all. It seems quite likely to me that the cure would be worse than the disease.
Secondly, and to me much more importantly, there is another issue we need to consider
and that is the law of unintended consequences. Briefly this states that whenever
you take action there will always be consequences you did not consider in advance
and did not intend. Since there are many more ways to be wrong than to be right
there is a better than 50:50 chance that these consequences will be bad. If the
original action is based on a false premise it greatly increases the risk of bad
unintended consequences. The precautionary principle is based on the belief that
there is no down side to taking action. The law of unintended consequences tells
us that there is always a down side and the cost versus benefit always needs to be
carefully evaluated before acting.
We are already seeing some very bad unintended consequences of the action taken so
far over global warming. The government driven initiative to use less fossil fuel
by diluting it with ethanol is causing massive forest clearing the Amazon basin (to
grow the ethanol feedstock) and is very significantly raising food prices causing
even worse starvation in 3rd world countries. Terrible as it is, this has not greatly
impacted on western society but the next phase most certainly will.
There is another very serious unintended consequence that I would like to raise here;
one that concerns me very deeply. When I listen to the public AGW debate I hear
very high profile politicians and prominent public figures calling for people who
openly disagree with AGW to be put on trial for treason. I hear many cases of people
losing their jobs because of voicing sceptical opinions. I hear prominent global
warming advocates refusing to enter into debates or trying to avoid debates by claiming
the science is settled, and by claiming we do not have time, we have only weeks to
act. I hear AGW advocates resorting to personal attacks against people who disagree
rather than addressing the technical issues they raise.
I hear AGW proponents claiming to be the under funded underdogs, fighting to protect
the planet against greedy capitalists, yet the reality is their funding is at least
1000 times greater than the sceptics funding. I see many reports of scientists refusing
to release their workings, thus preventing review of their methodology, despite the
fact that their work was funded by public money.
I see how the established media abandons balance in reporting by strongly favouring
proponents of AGW, ignoring or denigrating sceptics and forcing most onto blog sites
like this one. I hear some environmental groups and activists publicly claim that
its OK and even necessary to exaggerate the threat so as to get the public to engage.
I see the courts condoning acts of vandalism and even violence against essential
public infrastructure. I see high profile public figures supporting such acts and
claiming them to be reasonable and justified.
In short I see our society abandoning some of our most vital democratic freedoms
over this hysteria: Free speech, impartial enforcement of the law, balance in reporting,
freedom of information. These are freedoms our forebears gave their lives to bequeath
to us, they are our most valuable inheritance and we seem to be throwing them away
over an unproven hysterical hypothesis.
More recently I have read articles from England advocating individual ration cards
for petrol, heating oil, gas, electricity. Is water and food next? War time austerity
as an ongoing future way of life? A return to the agrarian poverty of the middle
ages? I note the new film “Not evil just wrong” has had to be distributed via the
Internet rather than traditional media. One step from distribution through an underground
network? Will that apply to all future sceptical writing? What about other writing
contrary to the popular opinion of the day?
These are the issues that differentiate between a free democracy and a totalitarian
regime and the further one goes down this path the harder it is to pull back. History
has shown us that the disease is far easier to acquire than to get rid of.
Notes and Links
Michael Hammer graduated with a Bachelor of Engineering Science and Master of Engineering
Science from Melbourne University. Since 1976 he has been working in the field of
spectroscopy with the last 25 years devoted to full time research for a large multinational