Cardinal Pell lecture peddles misrepresentations of climate science
- 02 Nov 2011, 12:00
- Tim Holmes & Robin Webster
In the UK, the government and opposition both accept the weight
of evidence which shows that climate change is happening and is
caused by humans. This is not the case, however, in other
English-speaking countries - notably North
Australia, which both have opposition parties which routinely
reject the science behind climate changee.
That's why it's interesting that Lord Lawson's climate skeptic
think-tank the Global Warming Policy Foundation chose to have its
annual lecture at Westminster Hall delivered by Cardinal George
Pell, Catholic Archbishop of Sydney last week, a story which was
reported in The Australian.
When the GWPF was launched in late 2009 it presented itself as
an organization that is "open-minded on
the contested science of global warming" but "is deeply concerned
about the costs and other implications of many of the policies
currently being advocated." This was recently reiterated when Lord
wrote in the Sunday Times that the concern of the GWPF is
"primarily in the area of policy: in the
light of the facts [about climate change], to the extent that we
know them and understand them, what policy is it rational and
proportionate to pursue?"
As with so much else of the GWPF's output however,
Cardinal Bell does not appear to have taken this on board. As
already noted by the Canadian site
desmogblog, his lecture, available on the
GWPF site, is remarkable for the number of misrepresentations
of climate science which it contains.
It would be difficult to thoroughly assess all of the scientific
errors in the lecture, but below we have picked out a few
After describing carbon dioxide as "not a pollutant, but part of
the stuff of life", the Cardinal went on to say that
"Animals would not
notice a doubling of CO2 and
obviously plants would love it. In the other direction,
humans would feel no adverse effects unless CO2
concentration rose to at least
5000 ppmv, or almost 13 times
today's concentration, far beyond
any likely future atmospheric
Increasing the proportion of carbon dioxide in the atmosphere
might not have a direct effect on animals and humans. But an
increase in carbon dioxide in the atmosphere of this level could
have unimaginable consequences. The IPCC concluded that the health
impacts of climate change will be "
overwhelmingly negative" and that "
the resilience of many ecosystems is likely to be
Their 'worst case scenario', Scenario A1F1, projects that carbon
dioxide will reach a concentration of approximately
1000ppmv by the end of this century, leading to a global
temperature rise of
more than four degrees. The Met Office has outlined some of the
impacts of a four degrees temperature rise
He goes on to say that
"The conclusions of the 2007
Fourth Assessment Report of the UN's Intergovernmental Panel on
Climate Change (IPCC) … are "essentially reliant on computer
modelling and lack empirical support"
The First Working Group of the IPCC's Fourth Assessment report
chapters specifically devoted to empirical observations of the
impacts of climate change.
Models are continually tested against historical observations,
through a process known as "
hindcasting". We have looked at this question in more detail here.
"[The IPCC's] speculations on
"the baleful influence of atmospheric carbon dioxide rest almost
exclusively on unvalidated computer modelling that rests on
unsubstantiated assumptions about the amplification effects of
water vapour, clouds and other unverifiable factors."
The warming effect of carbon dioxide can be demonstrated in the
laboratory - as shown in this BBC
video. We have known that carbon dioxide is a warming agent for
many years - Svante
Arrhenius first calculated the impact of changing levels of
carbon dioxide on the climate in 1896. That was followed by over a
century of discussion, testing, and refinement of the theory, a
process which provided a wealth of supporting evidence.
The amplification effects of water vapour are not
unsubstantiated; while on clouds, the IPCC both acknowledges
existing uncertainties and includes the writing of skeptical
"The predictions based on these
models "have been wrong for the last 23 years".
Models generally provide a good approximation, as
comparisons of model output to data demonstrate. It is also
worth noting that some - including sea-ice and
sea-level rise - have been conservative.
"The influence of various solar
mechanisms (such as sunspot activity) and changing ocean
circulation, which are poorly understood, are "omitted from the
climate models", as is the influence of major volcanoes
In the real world, climate scientists have not simply forgotten
activity - or about
ocean circulation, or about
volcanoes - and the impacts of all of these have been included
in climate models.
"Global temperature reached a
twentieth century high in 1998, corresponding to the strong El Nino
episode of that year. Subsequently, the continued warming
anticipated by the IPCC did not eventuate, and, after first
reaching a plateau, by 2010 temperature had cooled
This is the argument that keeps coming back and back. As we have
recently, and here in more
detail, a single decade is too restricted a period to use in
testing whether climate change is occurring, or a model's
predictions - because too much short-term "noise" clouds the
long-term "signal". As one scientist
put it, considering only 10-15 years of temperature is like
"analysing the temperature observations
from 10-17 April to check whether it really gets warmer during
Although the rate of warming has slowed over the last decade, it
has not stopped. The Royal Society
recently concluded that:
"each decade since the 1970s has been
clearly warmer (given known uncertainties) than the one immediately
preceding it. The decade 2000-2009 was, globally, around 0.15°C
warmer than the decade 1990-1999."
The observed warming has
fallen well within the predicted uncertainty bounds of the
IPCC, as discussed by the science blog
"The "medieval warm period" was real, global, and saw
temperatures exceeding today's"
It is possible that temperatures in the medieval warm period
(MWP) may have been comparable with today's - uncertainties remain
on this question, and coverage is somewhat patchy. But the
weight of evidence suggests that the recent temperature extreme
is unprecedented in the last 1,300 years. Moreover, temperatures
during the MWP actually varied quite widely across different
But mainly - the fact that climate has varied in the past is
simply irrelevant to the observed, human-caused warming that has
taken place since the mid-20th century.
"The ice-core records of the
cycles of glacial and interglacial periods of the last one million
years or so show a correlation between CO2 levels and temperature,
but the changes in temperature preceded the changes in CO2 and
cannot, therefore, have been caused by them."
The sequence Pell describes is correct; but this argument is
little more than a red herring. Climate change during ice ages was
triggered by other factors, such as
changes in the Earth's orbital cycle. Carbon dioxide then acted
as a feedback, amplifying the warming already occurring. This does
not undermine the
evidence that current warming is caused by manmade greenhouse
"I have discovered that very few
people know how small the percentage of carbon dioxide is in the
atmosphere. … today's total CO2 concentration represents less than
one-twenty-fifth of one per cent."
As former Director of the UK's Tyndall Centre on Climate Change
Research Kevin Anderson pointed out in a recent
debate with Nigel Lawson:
"This idea that they're only a small
part of the total gases in the atmosphere - of course that's true,
but it's a really silly thing to say. I mean … if you put a small
amount of arsenic into a human being, they don't respond
particularly well. So changing something that is really important
in the balance of the climate, even if it's a small part of that,
is actually hugely significant."
Such figures, then, are little more than a meaningless
distraction from the real issues.
Rather confusingly, Pell also states that the "case for the
sceptics…has "so far has been completely ignored by the Australian
media and political class". This statement would be somewhat
surprising to anyone who has been observing the torrent of
media articles rejecting the science of climate change; or the
vitriolic debate which has led to Australian climate scientists
receiving death threats. Like so much else of the rest of the
lecture, it is, simply, an inaccurate and misleading statement.