Cardinal Pell's climate hot air



Heaven + Earth, Ian PlimerOn Wedneday, the Sydney Morning Herald reported that 'a dire warning about the need to mitigate man-made global warning from a Vatican-appointed panel of scientists has not yet convinced Australia's highest-ranking Catholic', Archbishop of Sydney Cardinal George Pell.

The 'warning' came from The Fate of Mountain Glaciers in the Anthropocene, the first report released by the Pontifical Academy of Sciences, an independent body within the Holy See. It notes that today's change in ice cover (the most visible evidence of climate change) is happening at an unprecedented rate and is due to human-induced changes in carbon dioxide concentrations in the atmosphere.

The report echoes the positions of both John Paul II, who spoke at length about environmental questions, and Benedict XVI, who has expressed similar anxieties and has overseen the Vatican's endeavours to become the first carbon neutral state.

The Vatican's views, however, are not shared throughout the Church, and Pell's is the loudest and most persistent voice of dissent. He has not taken aim at the Pope for his views on climate change, but has been exceptionally vigorous in his criticism of climate change and climate scientists.

The difficulty is not that he holds heterodox views on this issue. We are all entitled to our opinions. What is concerning is Australia's most senior Catholic clergyman vigorously advancing a position that could be interpreted as a statement of the official stance of the Catholic Church in Australia.

Earlier this year, Dr Greg Ayers, head of the Bureau of Meteorology, painstakingly examined the scientific claims made by the Cardinal in a letter tabled in a Senate estimates hearing. In response, Pell called Ayers, one of Australia's leading atmospheric scientists with 140 peer-reviewed articles to his name, a 'hot air-specialist' who had made 'an unscientific contribution'.

This is but one of the more recent inflammatory statements by Pell, who often deploys more colourful rhetoric and invective on climate change than Tony Abbott or Andrew Bolt in his attacks on 'warmers'.

Across a number of years in his column in the Sunday Telegraph and the Catholic Weekly he has argued that the climate is not changing or, if it is, it is not changing as much as it has in the past, or if it has that this is natural, and that human beings have had no impact, or a negligible one, and that nothing we can do will make any difference.

He has repeated the talking points of climate sceptics that have been thoroughly refuted by climate scientists by reference to the peer-reviewed science (this is aggregated on the excellent website SkepticalScience run by Australian physicist John Cook, himself a committed Christian).

Pell relies on the work of Professor Ian Plimer, one of Australia's leading geologists, who is an atheist and outspoken critic of creationism. However Plimer's book, Heaven + Earth, which seeks to debunk climate change, has itself been debunked by Professor Ian Enting, a mathematician at the University of Melbourne, and by one of Plimer's own colleagues and friends, Professor Barry Brook.

On the basis of Plimer's work, Pell has:

  • said 'evidence shows the wheels are falling from the climate catastrophe bandwagon';
  • rejoiced in the 'wonderful irony' that winter weather in Copenhagen in December 2009 interfered with the 'huge jamboree on global warming';
  • claimed 'it is improbable that human activity can achieve significant global climate changes' and that climate researchers have 'fiddle[d] with the evidence' (he did not apologise once the University of East Anglia scientists were cleared);
  • criticised those who correctly describe carbon dioxide as a pollutant as 'propagandists capturing the language'; 
  • stated that there is no consensus among climate scientists; 
  • asked 'how long must global cooling continue before it becomes a problem for global warmers?' (even though we've just had the warmest decade on record); 
  • repeated that the temperatures in the Middle Ages were higher than they are today (the peer-reviewed science says they were not),
  • then delighted in what he called the 'delicious' fact that there was a cold snap in Europe in December 2010 in response to the claim by 'global warmers ... that 2010 ... [was] one of the hottest years on record'.

It should be no surprise then that Pell was listed in 2009 as a supporter of the Australian Climate Sceptics Party (although it must be noted that this was not at the Cardinal's request — he is not a member of any political party).

This is an extraordinary amount of commentary lavished by Pell on one issue — no other contemporary issue seems to have attracted his attention to the same extent.

On climate change Pell has adopted a peculiarly post-modern position, arguing that we should not accept at face value what institutions such as the US National Academy of Sciences say, but rather assess for ourselves whether we think global warming is caused by human activities or not.

It is ironic that he has bought into a post-modern narrative of science as inherently contestable and scientists as villainous, given that similar ideas are often expressed by radical environmentalists who adopt fundamentally anti-science views such as an irrational opposition to nuclear power.

Pell's interventions on climate change have prompted me to write to him on many occasions, passing on standard scientific texts on climate change, recent scientific papers of relevance and interest, and extending an invitation to organise a meeting with a leading climate scientist.

That offer has never been taken up, and there is no indication my correspondence has had the slightest impact. Pell is wedded to the views of Plimer, despite the fact that Plimer's key claims cannot be maintained, and his outlandish statements (about the contribution of volcanism to climate change for instance) have never been corrected.

Pell has said to me that when it comes to commenting on climate change he makes clear that he is simply speaking as an individual and expects no-one to accept his claims simply on his say-so. However he does not include this disclaimer each time he speaks on climate change.

The reality is that given Pell's prominence and his constant interventions in national discussions as one of Australia's best-known climate change contrarians, his views gain a good deal more attention in the media than the views of Australian bishops more generally.

Unless you are a close follower of religious affairs you are unlikely to be aware that the Australian Catholic Bishops Conference has heeded the mainstream science, issuing a position paper on climate change in 2005, and a statement in 2009 supporting Benedict's prayers for the success of the Copenhagen Climate Conference.

Pell's views on climate change have no scientific basis, and his interventions on the topic have done great damage to the reputation of the Catholic Church in Australia and to agencies such as Caritas that are taking practical steps to help vulnerable communities in developing countries whose livelihoods are being threatened by climate change.

There are no signs that Pell intends to step back from public discussion on the topic. In October he will deliver the second annual address to the Global Warming Policy Foundation, a climate sceptic think-tank in London, established by Lord Nigel Lawson, and which includes Plimer on its Academic Advisory Council. The first Foundation address was delivered by Václav Klaus, President of the Czech Republic, who argued that climate change is a ruse to justify a totalitarian ideology.

It remains to be seen whether Pell will speak on the same theme to his audience at Westminster Cathedral Hall, but it seems unlikely he will refer to any of the recent published science, such as the report of the Australian Academy of Science that identifies four lines of evidence (physical principles, the record of the distant past, measurements of the recent past, and climate models) to conclude that greenhouse gas emissions from human activities are the main cause of recent climate change.

It is, to use Pell's own words, likely to be more 'hot air', both in the sense of being unscientific, and also in being inflammatory.

Tim StephensDr Tim Stephens is Director of the Sydney Centre for International Law, at the Faculty of Law, University of Sydney and a parishioner at St Joan of Arc, Haberfield, NSW. He holds a masters degree in geography from the University of Cambridge, a doctorate in international environmental law from the University of Sydney, and writes on climate change science, policy and law. His latest book, co-authored with Donald R Rothwell, is The International Law of the Sea


Recent articles by Tim Stephens.

Bad week for Pell and climate change deniers

Topic tags: Cardinal George Pell, climate change, skeptic, Professor Ian Plimer, glaciers


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Existing comments

Great article, Tim!

I am a follower of religious affairs, and the ACBC's position on the issue. However, I was not aware of the extent of Cardinal Pell's resistance.

This is disturbing not only because many in the mainstream media, and in the community believe that Pell speaks for the Catholic Church (in Australia), but also because a significant portion of practising Catholics take their socio-political cues from Pell.
MBG | 20 May 2011

Pell follows Ian Plimer's book, but if you look at the entry for Plimer at SourceWatch, you'll see that Plimer is hopelessly compromised by conflicts of interest, being a director of four mining companies. His book has been pilloried by hundreds of climate scientists as complete rubbish. Both Pell and Abbott seem to have missed this.
Jason Robbelais | 20 May 2011

I for one am grateful for Cardinal Pell's questioning of the climate change hype. He does not deny that climate changes - all can see that - but he questions the anthropogenic cause - which is being used to tax people out of existence. Many time I have asked questions only to be met with a totalitarian type denunciation for having dared to ask questions of the current climate change enthusiasts. The earth's temperature is not rising and carbon is not a pollutant.

Cardinal Pell has the right to question a mass delusion which will beggar many people economically if the carbon tax is introduced.
Skye | 20 May 2011

Good-oh, if Pell thinks the Pope is wrong on this and continues to oppose the infallible thinking of His Grace, maybe we can all look forward to seeing Pell join Bishop Bill in 'retirement'?
Harry Wilson | 20 May 2011

I am pleased to see Dr Tim Stephens going into print about his long standing battle with Cardinal Pell. I personally believe that it will make no difference to the Cardinal and not change his views one iota. From that point of view it is a waste of time, and giving more air to his hot air.

On the other hand it does expose the Cardinal to further scrutiny on his much publicised comments in this area. It also highlights yet again the extraordinary success of the publicity machine that he employs that he keeps being asked to speak as the 'leader of the Catholic Church in Australia', which he is not.

It would perhaps be best if the Cardinal took note of the words he once wrote to me in response to a letter about an issue involving his administration of the Sydney Archdiocese: "I have always believed that if you know little about a topic it is best to remain silent."
Shane Wood cfc | 20 May 2011

I don't think we should worry too much. The number of people who pay attention to what Pell says is very small.
Peter Downie | 20 May 2011

But the earth's temperature is rising. The last decade was the warmest on record. What planet is Skye on?
Michael Grounds | 20 May 2011

Great article Tim.

I have also written to Cardinal Pell on numerous occasions over the past three years. He seems to base he entire rejection of human induced climate change on the need to "defend us against pagan influence".
This is absurd, and shows that he position is purely ideological, rather than theological or scientific. That he is out of step of even the very conservative Vatican, shows how far to the political right he sits.

How he has conducted himself in this discussion, with personal and degrading attacks on the scientific community, and political leaders who take action on climate change, is extremely disturbing for an representative of our Church. He touts his message in the media once a week, and does not subject himself to a deeper explanation of his views.

I have made the same point to the ACBC and the Nuncio in regards that Cardinal Pell doesn’t distinguish between his personal comments and that of the Church on climate change. They have taken no action I am aware of. There is no doubt they would not be so lenient if his personal comments contradicted the hierarchy on celibacy or women ordination!

In reality, he has become irrelevant in this debate, and the ongoing need all nations will face to tackle the results of human induced climate change over the next century.

The central issue for the Australian Church now is that any stance, or comments he makes on other issues, are dismissed and ignored, as he has lowered the position of the Archbishop of Sydney, and is not taken seriously by the political and wider community at large.

Damien | 20 May 2011

Thank you Tim for a timely and scholarly treatment of a subject where scandal, in the sense of deliberate misleading of the truth, is never far from the reality.

As a former colleague of Prof. Ian Plimer in the University of Melbourne, I enjoyed his entertaining and lively discourse. An excellent lecturer, when on firm ground he is highly persuasive.

However as an avowed apostle of the mineral industry, he came early to the conclusion that his future was dependent on his being spokesperson for its agendas. That remains his justification today.

Unlike Pell, Plimer is highly aware of the disastrous climatic implications of our continued and mindless dedication to coal. He cannot afford to say so. But like Pell, he too is committed to that sense of narcissism that comes from frequent appearances in press and public media agendas. Both are victims of self-image promoted by media sensationalism. Although sadly delusional, both will soon join other irrelevant voices as the world awakens to the reality of our own irresponsibility.

Jim Bowler | 20 May 2011

Thank you, Tim, for an excellent article.

Cardinal Pell shows great inconsistency regarding this issue. At once he rejects the primacy of conscience and insists upon compliance with religious authorities' world view and he rejects the Vatican on a directive about man-made climate change.

David Lukas | 20 May 2011

For a Prince of the Church who usually defends the Pope and The Vatican Curia with great courage and perseverance I find his criticism of the scientists who contend that much of the adverse changes taking place in the earth's climate/atmosphere puzzling in the extreme.

Regrettably in my view his stridency on this issue of climate change undermines the cool and well argued approach he often takes on matters of faith and morals.

Uncle Pat | 20 May 2011

Cardinal Pell is increasingly isolated within the church in Australia regarding climate change science.

That publication by the Australian Academy of Science, for instance, is being used in classes of dozens and dozens of Catholic schools.

Most Catholic leaders think Cardinal Pell sees the climate change debate as more of a useful a parable than as something to take seriously, ie. he's intellectually bankrupt on climate change and embarrassing for it.

Can anyone name another senior Church figure who supports Cardinal Pell's position on climate change science?
MrsD | 20 May 2011

It takes magnanimity of spirit and humility to change a position of passionate adherence to a belief that in the light of valid investigation is overwhelmingly shown to be incorrect.We should not criticise our cardinal. We should pray for him in the hope that he become enlightened and not run the risk of ridicule which would not be in the best interests of our church
john frawley | 20 May 2011

An excellent and understated article about George Pell's ignorance of the matter. Thank goodness there are both scientists and progressive theologians who are able to give a different, more accurate view to the public.
Rex A E Hunt | 20 May 2011

I am a practicing Catholic and will continue to be so until the day I die. My comments are, who listens to Cardinal Pell? I worship is a large parish in Queensland and have yet to come acoss anyone who likes or listens to him. The other issue here is that his views are contrary to that of the church.
Dave | 20 May 2011

Thanks for the article Tim. It's good to see calm, informed views on this matter coming forward and finally getting a hearing in the Catholic community.

Skye - think what you will about the current political policy labelled the 'Carbon Tax', but the reality is, we need a price on pollution in some form or another and we need it now.

If we don't get one, we'll all end up paying more in the end, and it won't just be in dollars.
Jude | 20 May 2011

Tim, you say what needs to be pointed out increasingly with some insistence, candour and reason. I think that Shane Wood, Peter Downie and others articulate this.
I believe that +Pell rather enjoys this kind of jolly banter in the public forum. There is no Magisterial border to be defended after all, no eternal truth, no great matter of doctrine or discipline to be upheld that cannot be dealt with in an episcopal oneliner or apologia by proxy from devout converts in the Murdoch press.
The 'media' dine out on the 'Head of the Catholic Church in Australia' fare while the fact is that he is the Ordinary of a geographically tiny jurisdiction. Few, outside the Remnant of the Faithful pay him much notice at all.

I am reminded of the words of John Ralston Saul (1995),
'The Captain of the Titanic was no doubt pleased that his male passengers in first class remained calm as they waited to drown. Had they been less controlled, they might have found some small satisfaction in passing their time by throwing him overboard.' -The Doubters' Companion.'

David Timbs | 20 May 2011

The Vatican does not claim authority on science, but on morality. The statement issued by its Pontifical Academy, although written by scientists, is really a statement about moral obligation.
Cardinal Pell is not a scientist. Neither am I. We are, however, both Catholics, and concerned about moral obligations. Failure to mitigate an identified risk involves morality. Let it be conceded that it has not yet been demonstrated beyond doubt that carbon dioxide and methane emissions are a cause of global warming. But there is a substantial body of credible evidence in favour of that proposition, as evidenced by the Pontifical Academy. Is it morally permissible to take the risk?

If the Pontifical Academy is right, and we do nothing to reduce carbon dioxide emissions, the consequences will be catastrophic. If Cardinal Pell is right, but we do reduce carbon dioxide, no harm is done. He is prepared to take the risk. I am not.

A;an Hogan | 20 May 2011

Is Pell going to be forced to retire as he has differing views to the Vatican official line?????
Peter Lynch | 20 May 2011

Where does all this situate that other well-known theologian, Tony Abbott, on climate change?
Frank Golding | 20 May 2011

Why would anyone take any notice of what cardinal Pell says about climate change.The very fact that his articles are published in the Murdoch press aligns him with Alan Jones Piers Ackerman,and all "serious" right wing "thinkers".

Unfortunately for The Church cardinal Pell is also an irrelevence among his flock. Those of us left simply ignore him and the vatican, go to Mass say our prayers and lament the loss of our children to the faith directly as a result of their actions.

We are also angry because of his and the Vatican's attitude to Issues like the bishop of Toowoomba,both fathers Kennedy and the attempts at every turn to put the "genie "of Vatican two" back in the bottle"

Our belief is eventually it wont work ,the faithful are a lot smarter than Cardinal Pell or the Vatican .Come to think of it that is what Bob Brown said about Cardinal Pell's great friend Tony Abbott,with the same justification
paul tocchini | 20 May 2011

Thank you for this thought-provoking article.
Cardon dioxide increases are not an exact fit with the rise in emissions of carbon dioxide due to modern industrialisation. A hockey-stick graph by Michael Mann and others, which attempted to show an exact fit, was based upon unverifiable data - and employed unprofessional and ultimately unreliable methods. Professor Edward J. Wegman, statistics professor and chair of the US National Research Council’s Committee on Applied and Theoretical Statistics, lodged a report with the US Congress in 2006 detailing the problem.

In fairness to Pell, the IPCC has been very influential in the Climate-Change debate, and the reliability of it as a source of data then becomes critical.

Defects in its processes were not widely known until the Climategate e-mails were leaked/hacked from the website of the University of East
Anglia in November 2009. The most well-known (amongst the 1 000 or so) was an e-mail from Professor Philip Jones to Michael Mann and
his co-authors dated November 16, 1999, which stated:
“I’ve just completed Mike’s Nature trick [referring to the journal where the now-discredited-but-highly-influential 'hockey stick' graph results first appeared] of adding in the real temps to each series for the last 20 years (ie from 1981 onwards) and from 1961 for Keith’s to hide the decline ... Cheers Phil.”
This hiding of a decline by this Professor would have a serious impact on public perceptions and thus voter support for political response to methods to contain temperature increases believed to have been caused by anthropogenic global warming (AGW). The problem is that a lack of openness and honesty then creates a lack of trust in anything emanating from a source which has shown its self-admitted willingness and capability to alter data in this way. So even if cleared of deliberate fraud, there has been a rupture in trust which needs to be restored.

In the meantime, any analysis which omits reference to solar influence, clouds, the earth's orbit, oceans, El Nino, deforestation and the earth's history, focussing instead on AGW as the sole cause is not holistic enough and could only present a skewed picture. The blinkered approach can only increase doubt and be counter-productive. The truth - the whole truth - would increase public confidence. If it emerges that the key influence is man-produced carbon dioxide emissions, then that needs to be addressed (and there are many ways in which it could be: lateral thought can be applied to the solutions, which may lie in scientific and environmental responses, and not necessarily in economic ones such as taxes or carbon credit swaps). Fear of looking at all contributing factors can be misconstrued - which reduces public confidence, which then translates into lack of support.

In a free democracy, all people (Pell included) are encouraged to have a voice on important topics which will affect how we live. It should be welcomed, not shut down. Especially if it invites more scrutiny, greater lateral thinking and ultimately, better professional practices and a better society.

Sophie | 20 May 2011

Plimer, a geologist, debunked by a mathematician? Look, there's good reason for moving on from fossil fuels regardless of whether we're heading for climate catastrophe or not. Alarmism is the problem, and is just as bad as the other extreme that sees a global conspiracy behind it all. I wish people would read the 'summary' of the IPCC Fourth Report. It does not warn of catastrophe but points to a (computer modelled) worst case scenario that is entirely manageable. Al Gore, Tim Flannery and Robin Williams are no better than Lord Monckton when they pretend there's some kind of official consensus that the oceans may rise 100 metres. Please, folks, read the IPCC official summary.

What is needed is less alarmism, less subsidies to Green entrepreneurialism, and instead a huge increase in government funding for Research & Development into the range of alternatives to fossil fuels (which will become more expensive with inevitable scarcity caused by the industrialisation of China, India and Africa). This range includes nuclear (Barry Brook being a most effective spokesperson for nuclear power) but how about funding for research into nuclear fusion as well as fission? We should be part of an international effort on this.
Barry York | 20 May 2011

We are truly fortunate to have George Pell as our very own Prince of the Church. His wisdom and humour give power to his insights into the world at large. He has great ambition to direct; perhaps he should channel his energies into leading. He would, if he could, be a Thomas de Torquemada [1420-1498] but he can’t; there have been too many slips along the way. He has become an ‘Auberon Quin’ facsimile. This character created by G K Chesterton cared for nothing but a good joke and by his actions created chaos, as indeed would our prince, if we took him seriously...
Dermott Ryder | 20 May 2011

Scripture is a more reliable guide to what should be done than the pronouncements of a short-sighted cardinal. The earth is ours, and everyone else’s, that we may care for it and delight in it. It is all we have and our time is short. The earth is good and it can be renewed. The problem is that it is we who can mess it up and be blind to the fact that this is what we are doing. Damage occurs through our own selfishness, ignorance and laziness. These things are on huge display in our country at the moment, where we would rather accept denial of climate change and refuse to hear commonsense than be seen to sacrifice the things of the earth that we, in our foolishness, believe to be our possession. Scripture, like science, shows us what will happen if we ignore the signs and simply live lives of personal greed, indifferent to the needs of others or our inherited earth.
Desiderius Erasmus | 20 May 2011

I don't agree with this statement! There is a definite climate change!
André VANDER LINDEN | 20 May 2011

I think there is plenty of hot air on both sides of the debate. The fact that (believe it or not) there are formidable scientists on both sides indicates to me that the science is obviously still disputed; that people will believe what they want to believe; that the whole debate has taken on a close-minded blindly religious fervour by people on both sides. Here's my take on all of this: Climate change is real and it has been so since the beginning. Humanity has been given stewardship of the world, which, amongst other things, implies a duty to protect the world and everything in it; that we must strive to reduce pollution as a matter of principle, regardless of its contribution to climate change (while the degree to which humans contribute to climate change will continue to be debated, the fact that humans pollute the world cannot be disputed); that we should move to more efficient and sustainable forms of energy that 1) do not force up the price of food beyond the affordability of people in developing countries [eg taking up valuable arable land to grow crops for energy and not for food], and 2) that new forms of energy should not be a monopolised power in the hands of the rich, and unaffordable to the poor, especially in developing countries. Can someone please answer this question for me: Traditionally, one of the main justifications of motor racing (Formula 1 and the like), has been the fact that it promotes development and efficiencies. If this were true, and if policy makers were genuinely concerned about issues such as peak oil, climate change, etc, then why don't our governments say "Ok, you are welcome to have your formula 1 races, touring car races etc, but on the condition that you use renewable forms of energy to power your vehicles, and the creation of those forms of energy must be ethical (ie not from grains which should have gone to feed the poor)." I am sure that better forms of energy would be harnessed immediately if the racing industry were encouraged to lead the way. The fact that governments haven't taken this action already says to me that they don't take issues such as peak oil and climate change seriously. And that goes for both major parties (and the watermelons too).
DJ Byrne | 20 May 2011

The moral issue focuses around the Cardinal's view that whatever Australia does it will make little impact globally. I would have thought that a proper christian view is that we should do the right thing regardless of whether other people follow suit. Secondly, I am not a Catholic but I am suspicious of the argument that a Cardinal promotes personal opinions other than those of his Church. That doesn't seem to apply to others in the Catholic church who have expressed personal opinions.
Rev. Harry Herbert | 20 May 2011

I usually disagree with George Pell's views on matters such as primacy of the papacy and non-primacy of individual conscience, but I agree on his view against anthropgenic CO2 caused global warming. Sophie has written here an excellent paper on the subject. Others have said Ian Plimer is debunked. All of us should read Professor (Geology at Townsville Uni.) Bob Carter's book, published in 2010,"Climate Change - The Counter Consensus". There is NOT a complete consensus for IPCC conclusions. It and its 'climate change scientists still cannot quantify and measure the proportion of human activity that is or may be responsible for global warming. They only guess and then the alarmists wind up to try to make us feel guilty and themselves important!
Gerard Tonks | 20 May 2011

Harry Wilson - there is a different between scientific discussion and matters of faith declared by the church. Pell has every right to comment on climate change - it is part of a civilised society to have discussion and debate on such matters. Or are you opposed to discussion and debate?
Skye | 20 May 2011

Pell would be delighting in all these responses. They give him.prominence....and the Australian church unfortunately by association. Did he ever hear in his childhood about the wise old owl?. The more he heard the less he spoke. Why can't he be like that wise old owl? As a church we would all benefit.
leo kane | 20 May 2011

Thank-you Cardinal Pell for speaking out against this "climate change" hoax. I was a Y2K expert back in the day and this is exactly the same sort of hype that i joined into back then. In any case this "climate change" issue has nothing to do with religion - it is just pure politics. The Vatican shouldn't be dirtying itself by entering into the discussion. By the way, it is becoming more common that people don't even believe that humans exhale carbon dioxide as part of normal respiration - It is disturbing how basic science has now been hijacked my hype around this pseudo science.
Michael | 20 May 2011

Thank-you Cardinal Pell for speaking out against this "climate change" hoax. I was a Y2K expert back in the day and this is exactly the same sort of hype that i joined into back then. In any case this "climate change" issue has nothing to do with religion - it is just pure politics. The Vatican shouldn't be dirtying itself by entering into the discussion. By the way, it is becoming more common that people don't even believe that humans exhale carbon dioxide as part of normal respiration - It is disturbing how basic science has now been hijacked my hype around this pseudo science.
Michael | 20 May 2011

Here we go again. It seems that the Middle Ages have returned. During the Middle Ages anybody questioning the political, scientific or religious believes was a heretic and killed. In 2011, anybody questioning anything about the official politically correct view of this world is no longer burned at a stake. Maybe because burning people at a stake is a breach of the EPA Act or cause global warming? Nevertheless, punishment of these heretics is swift by public humiliation and name calling. The worst of the names to be used is now a “Climate Sceptic”.
Beat Odermatt | 20 May 2011

Since, indeed, the last decade was the warmest on record, may I suggest that we continue to refer to this happening as GLOBAL WARMING, rather than climate change. Climate change suggests the possibility of betterment - global warming is happening, unless.
Joyce | 20 May 2011

Great article but it will make no difference. The good cardinal has made up his mind despite any fact to the contrary - So why bother to listen to him? I stopped and I feel much better for it!

Jeff KETTERING TAS 7155 | 20 May 2011

Cardinal Pell as a leader of Christ's church has a responsibility to speak of the real risks of climate change to the planet and God's creatures, especially the poor and disadvantaged. Even the most skeptical of the climate change sceptics accept the fact of some level of risk, despite their scepticism. To ignore a risk of catastrophe rather than seeking to mitigate the risk is simply irresponsible.

For a leader of the Church, let alone a cardinal, to encourage others to ignore a risk of substantial harm, is not only to fail in his responsibilities but is an abuse of the position from which he derives his influence in society. Catholics must demand a higher standard of behaviour from their bishops. Cardinal Pell's improper use of his position is another failure in church leadership along with the Church's cover-up of paedophilia, the unChristian dismissal of Bishop Morris, the direction that Catholics must not discuss women's ordination, and other failures to focus on Christ's message of love. Catholics need leaders committed to Christ-like leadership and must demand this of their bishops.
Peter Johnstone | 20 May 2011

For God's sake, will the Doubting and Denying Thomas into the Earth's wounds and see for themselves the damage done and the disasters to come. This is not alarmism, it is the cold, hard scientific reality and reality is not a matter of 'belief' it just is!
Rod Quantock | 20 May 2011

What the Cardinal says is only an issue because Tony Abbott is talking as if he believes him (rather than believing the 95% of relevant scientists who say we have a problem and that it's serious).
Geoff | 20 May 2011

George Pell's statements - they are not valid enough to be 'arguments' - fall into the same category as his fellows in this area: politics, not science. The scientific case for human induced climate change is now well established, but the politics linger, here and in other countries. Businesses affected by even the possibility of climate change have moveed on, including such change in their strategic plans; they can't afford the luxury of the deniers' hot air.

Pell says he does not belong to a political party but his actions and words in recent years, including omissions, show clearly which side he bats for.
John Garrett | 20 May 2011

Perhaps George Pell is a professional contrarian. Such people are popular with the vested interests who like nothing more than a high profile ignoramous to fire their bullets for them. Carbondioxide is one of the most potent substances on the planet, driving as it does all the life support systems via photosynthesis. As all modern species and ecosystems evolved to their present state at a Carbondioxide concentration fairly steady around 280 parts per million the present 40% increase in this concentration not only provides a thicker "blanket" to keep the warmth in but also an alien level of carbondioxe to rattle the balance in terestrial and oceanic ecosystems. Only a "happily uninformed" person can remain unaware or unresponsive to this.
Mike Foale | 20 May 2011

While climate change cynics cannot be prevented from having opinions on anthropomorphic climate change, the value of such opinions can only be measured by how closely it is in accord with the science.

These cynics bring up side issues such as flawed political decisions of how the costs associated with climate changes will be paid for. These issues are irrelevent to the science.

Others retreat into complete falsehoods: "The earth's temperature is not rising and carbon is not a pollutant." (What is soot?) Or would have you believe that climate scientists are saying that "AGW [is] the sole cause" of climate change. Or repeat falsehoods about the meaning of private e-mails between scientists. Or repeat falsehoods about climate scientist altering data. (The reality is that one of the most famous cases of altered data was the reproduction in black and white by climate change cynics of a graph, originally produced in colour, that was used to "prove" that average temperatures were not rising, when in fact the original coloured graph showed that they were.)

The reality is that the science overwhelmingly supports the position of the bulk of climate scientists: that human activity is effecting climate change.
Richard Moore | 20 May 2011

"Fate of Mountain Glaciers in the Anthropocene"

The Declaration by the Working Group Commissioned by the Pontifical Academy of Sciences reads as follows:

"We call on all people and nations to recognise the serious
and potentially irreversible impacts of global warming caused
by the anthropogenic emissions of greenhouse gases and other pollutants, and by changes in forests, wetlands, grasslands, and other land uses. We appeal to all nations to develop and implement, without delay, effective and fair policies to reduce the causes and impacts of climate change on communities and ecosystems, including mountain
glaciers and their watersheds, aware that we all live in the same home. By acting now, in the spirit of common but differentiated responsibility, we accept our duty to one another and to the stewardship of a planet blessed with the gift of life.

"We are committed to ensuring that all inhabitants of this planet receive their daily bread, fresh air to breathe and clean water to drink as we are aware that, if we want justice and peace, we must protect the habitat that sustains us. The believers among us ask God to grant us this wish."

One hopes that Cardinal Pell himself, and those Roman Catholics elected to prominent positions in Australian political affairs reflect on this declaration, issued under the imprimatur of the Pontifical Academy of Sciences.
David Arthur | 20 May 2011

Great article, robust correspondence. Cardinal Pell's columns in "Catholic Weekly" and "Telegraph" influence many less well-informed people who respect the authority of his office. Climate chsnge seems the only issue outside faith and morals on which he expends so much public energy and writing effort. This personal frolic is deeply irresponsible. It risks discrediting snd confusing the Church in Australia, as well as himself.

I hope that informed by this frank correspondence, His Eminence will think again - or, failing this, that someone in the Vatican might have a quiet word with him? Would ES like to send him a copy of "Crunch Time", with my respects?
tony kevin | 20 May 2011

Cardinal Pell is deluded about climate change.

There was a great discussion entitled "An analysis of climate change denial" on the ABC Science Show last Saturday at
Peter Horan | 20 May 2011

Commenter Sophie apparently hasn't caught up with the recent news that Edward Wegman et al have been forced to retract an article arising from their study as a result of plagiarism and sloppy scholarship. That's perhaps not surprising - the news sources on which I assume she relies have been very quiet on the topic.
John Quiggin | 20 May 2011

Interesting in the discussion is the note of hysteria. "How dare anyone doubt the word of a PEER-REVIEWED scientist?".
"Plimer is hopelessly compromised by conflicts of interest...". One may note that many of the PEER-REVIEWED scientists have a financial interest in the work: government grants and such.

It would be clearer if the critics of Cardinal Pell would distinguish between "the Vatican" and the Pontifical Academy of Sciences.

Someone wrote that the East Anglia scientists have been exonerated of something. Of what? It is evident that they attempted to quash dissenters from their views. One need not be a PEER-REVIEWED scientist to recognise censorship.

Writing as an American, I find that Cardinal Pell has a certain Australian brio. He certainly knows how to stir things up.
Gabriel Austin | 21 May 2011

No sooner do I send off a reflection on this discussion, then I read an account by an Australian scientist - David Evans - which reinforces Cardinal Pell's scepticism.


I wish you guys down under would get your stories together.
Gabriel Austin | 21 May 2011

Pell says that he "expects no-one to accept his claims simply on his say- so".....Hopefully,he wont be disappointed as the laity rise in influence with the solidarity of "people power", to take leadership in the Church seriously. May they rise up in confidence to let the Spirit lead them and free us from the 'hot air' of power, pomp, prestige, ultra right winged politics and the consequential flow of oppression, suppression and gross injustice.

Diana Law s.g.s. | 21 May 2011

Great article TIm,
The fact we are exploiting the earth's resources including Coal and Oil at unsustainable rates is morally wrong in the first place. In Geography 101 or Physics 101 for that matter, I am sure the theory surrounding the impact of increased CO2 in the Atmosphere/Oceans, greater than any time in at least 10,000 years must impact the climate in a negative way, is being taught or should be.

What worries me is that if we do not curb our use of the earth's finite resources, then unborn generations will suffer untold harm thanks to our greed.While I do not think I will be around when the climate becomes seriously threatening to the environment, my children and now my grand child will be!

I thought that the sin of greed is one of the seven deadly sins?
Gavin O'Brien | 22 May 2011

Cardinal Pell needs to take notice of the pope, and not be so silly about this serious moral issue. the pope has done the right thing in putting solar panels on the
Vatican roof. Lets hope that Cardinal Pell does the same thing.
maryellen flynn cowra n.s.w. 2794 | 22 May 2011

Mention Cardinal Pell and you are guarantee-ed to attract a raging tide of fury... whether its climate change, life issues, the 'price of fish in China' ! People here on this site,seem to simply love an opportunity to vent their fury at Cardinal Pell!

I'm not sure I agree with his position on climate change, but I do appreciate another voice in this zealous quasi-religious 'debate' about climate. We are being called to ' believe'... called to 'trust'.. to 'hope' .. in the climate change 'doctrines'. Questioning any aspect of the climate change "canon of beliefs" is greeted with calls of 'heretic', 'earth destroyer' and other emotional tags.

Let's keep the debate raging. If Cardinal Pell demands of climate change gurus, better explanations and better research proof, then I say, good on him. (the money we are about to throw at this climate change 'problem' demands water tight proof.)
CMD | 22 May 2011

Cardinal Pell should spend more time considering a more direct problem for the Catholic Church - the treatment of victims of sexual abuse by his clerics and the arrogant attitude displayed towards the laws of nation states by the Vatican in regards to this.
Joe Logan | 22 May 2011

Sophie argues:

"This hiding of a decline by this Professor would have a serious impact on public perceptions"

The only decline that was hidden was a failure by a few proxies to continue following actual temperature. This does not mean that those proxies must be no good earlier or that the vast majority of proxies used for reconstructions are not satisfactory. Refer to Peter Sinclair's video . This "hide the decline" issue has been subject to an enormous misrepresentation by people who want to avoid their responsibilities to the world at large.
Chris O'Neill | 22 May 2011

I'm happy to see both Pell and the Vatican talking about climate change for a while. It gives gays and lesbians a bit of a break.
Michael Elphick | 22 May 2011

@Environmentalist irrational opposition to Nuclear power:

How about the rational opposition to Nuclear power. My father was a nuclear scientist and an environmentalist so I grew up hearing all the virtues of a nuclear power industry. (And surprise when things did go wrong).

What on paper looks to Monbiot like a clean source of power is in practice dirty, wasteful of water, inefficient (still waiting for 4th gen to get a process over 10% efficient) and leaves a toxic waste product that is sitting around in the roofs of reactors to get blown because we don't know what to do with it. There is huge bias in the scientific community towards nuclear power because they think rational planning means no radiation poisoning — ever — and forget we live in a corrupt world. It also means lots of interesting work for nuclear scientists; not everyone is good enough to get a job at Cern.

The amount of artesian water being used to mine yellowcake is destroying natural springs in NT and could be used much more productively later in this century for agriculture (eg 1000s of acres of date farms).

As for Pell, what a dinosaur but he's emblematic of many people in Australia who just can't let go of their sense of entitlement. Nor can these deniers admit their complete lack of understanding of scientific research methods and principles and seem to fear the scientist's role in society — despite science's centrality to their privileged existence (hyper-wealth, technology, medicine much of which is exclusively preceded by scientific endeavour).
Alastair Leith | 22 May 2011

Can someone please explain how Cardinal Pell's views on Climate change and human agency will play out for the people living in the Pacific Oceans as their homes are slowly submerged? I hope they don't have to place all their trust in God alone. Or for those of us for whom the economic impact of climate change will hasten our journey to meet our Maker?
Elizabeth Mulrennan | 22 May 2011

Skye does not say where she gets her information from about temperatures not rising and CO2 is not a pollutant. I would like to believe it, but I can't find the evidence. I have read Plimer. Even I found very serious inaccuracies, and either sloppiness or fraud. The Hockey stick, Sophie, has not been "debunked". It has been modified. Words do matter. They are dangerous and can hang you.
Ann Long | 23 May 2011

I have never considered that Cardinall Pell, Tony Abbot, Andrew Bolt, Allan Jones or Pauline Hanson had anything intelligent to say. Their views were long ago known to be morally reprehensible and unchristian. Great article and well worth spreading the not-so-good news.
Annabel | 23 May 2011

If Tony Abbott is the love child of Donald Trump and Sarah Palin, George Pell would be the love child of Fred Nile and Pauline Hanson.
AURELIUS | 23 May 2011

Dear sophie, You'll be pleased to note that the Wegman report has been retrtacted: By Dan Vergano, USA TODAY In a story in Monday's newspaper, we reported on the federally-funded 2008 Computational Statistics and Data Analysis study headed by Edward Wegman of George Mason University. Echoing charges of plagiarism in a 2006 Congressional report by Wegman and colleagues that was critical of climate scientists, experts have noted apparently copied text -- including portions taken from a Wikipedia entry -- in the CSDA study. Journal editor Stanley Azen of the University of Southern California, says the journal will retract the 2008 study, wiping it from the scientific record.
sillyfilly | 23 May 2011

Dr Stephens, I followed your link to those who "correctly describe" carbon dioxide as a "pollutant".

The report doesn't mention pollution at all!

It says that increased CO2 enables plants to grow more efficiently and divert more resources into self-defence such as increased toxins.

How is causing an organism to grow more efficiently and equip itself better in the struggle to survive, an act of "pollution"?

And what about CO2 increasing growth in plants we use that don't have any substances which are toxic to us in any relevant sense?

Plants will stop growing at CO2 levels of under 150 ppm, and seriously adverse negative direct impacts of CO2 on humans ("pollution" in the normal sense of the term) kicks in at 5000 ppm.

Since 1960 CO2 has gone from about 310ppm to 385ppm.

Pollutant? I think the Cardinal has the better view.
HH | 23 May 2011


Many thanks for your comment.

The link I gave to CO2 being a pollutant is to recent research showcased on the ABC TV program Catalyst which shows rising toxin levels in certain plants grown at moderately elevated levels of CO2 (and by the way rising CO2 does not mean increased productivity for all plants).

Dr Ros Gleadow makes the following observation on the program: 'In about 50 years time or even 100 years time eucalyptus leaves will have trouble supporting arboreal herbivores like koalas because the phenolic concentration will be too high and the protein level too low.' (Perhaps you'd be interested in reading some of Dr Gleadow's papers:

So, quite apart from CO2's warming effect in the atmosphere, and its acidifying effect in the oceans, this is another example of CO2 functioning as a 'pollutant'.

This means that CO2 at certain concentrations meets the Oxford English Dictionary meaning of pollution: 'A polluting agent; esp. a noxious or poisonous substance which pollutes the environment.'
Tim Stephens | 23 May 2011

Thank you to those who have given feedback, it is important to help arrive at the truth. Nobody has all the answers, so it is simply great to have a forum where people contribute thoughtfully and respectfully to the central issues raised by the article. Eureka's comments are often of a higher standard than elsewhere in the blogosphere!

Ann Long, I agree with you that words matter - so does correct attribution of a word, using quotation marks. I did not use 'debunked'. I am grateful for the input relating to the highly influential hockey-stick graph (ie that it had to be modified) - thanks for that.

Our blog thread shows how easily errors can be made. Correct attribution is very important. Sincere thanks to those who alerted me to the latest re Wegman's report. He has challenged the accusation of plagiarism, so it sounds like the story does not end there. An accusation, even a serious one, is not a conviction. It can be a horrible experience for an innocent person. Also, the veracity of the content of the Wegman report could remain intact - it remains to be seen.

In the meantime, establishing trust amongst all the view-holders on this critical issue of climate-change is probably the main goal, because you cannot get very far in any endeavour which is important, without it.

The approach being debated in Australia currently is worthy of further analysis. A blanket tax with compensation which will defeat behaviour-modification goals and possibly send certain industrial work (such as our steel-production) to higher-emitting countries, will not decrease global emissions (the stated purpose of the tax). The effectiveness of the tax in achieving its goals must be laid squarely before the voters (the tax-payers of the nation.) Effectiveness must be demonstrated by measurement.

Even if switching to renewables is desirable, and the carbon footprint of the methods employed is able to be justified, this is a separate argument to whether a carbon dioxide tax is the best measure for our country to address the posed problem of AGW global emissions.

(Certainly the Canadians in their recent election results have shown that they do NOT think carbon-pricing in a lone country with a comparable economy to ours is the best solution.)

Sophie | 24 May 2011

I’m grateful for your response, Dr Stephens, and I don’t wish to imply that the effects of CO2 at various levels on our native species isn’t an important issue. I fully accept the findings of the linked Catalyst program.

I think, though that the description of CO2 as a “pollutant” is something we’ll have to disagree about.

The reasoning seems to be this: CO2 increases bring about increased levels of toxins in plants. But toxins are pollution. Therefore CO2 is a pollutant.

I dispute the second premise.

Toxins which form part of a plant’s natural defence mechanism are not “pollution”, just as venom in a snake is not “pollution”. If these were to be termed “pollution”, then it would be true to say that any plant which naturally produces toxins is, on that account, a pollutant; that venemous snakes are pollutants; that Farmer Jones who produces a crop which happens to bear naturally occurring toxins is a polluter, and so on.

The word “pollution” or “pollutant”, I submit, involves more than just the existence of or creation of, a toxic substance. It must be created in some non-natural way. And/or: it must be dispersed through the environment in some non-natural way.

HH | 24 May 2011

To be fair to the good Cardinal, he is probably expecting to be able to recant on his deathbed.
Jason | 24 May 2011

FANTASTICALLY written Dr Stephens. I agree with you entirely on every point. What astounds me as a mother of four children, is that people with Pell's views don't seem to consider that by continually putting their views out there (without acknowledging each time that these views are at odds with those of 99% of experts on this particular science) they are undermining action that might JUST give my children (and therefore all the world's children) a chance at living a reasonable future.

Even if Pell can't be convinced by 99% of experts, surely he can concede that it's better to do what you can to avoid catastrophic harm (just in case it's true...) than to encourage taking no action (because he believes it's not true) when the harm caused by that lack of action is so great?

Personally, I would like to ask Cardinal Pell, is God going to be more proud of you for a fine public speech in London amongst fellow sceptics (what good would come from this, even if you were correct in your views?) OR for doing what you can to ensure that my children amongst millions of others are able to live in a world without catastophic drought, famine, disease and weather disasters?

Just one more point that occurred to me as I sat on Sunday watching a well-meaning priest give a very dry and academic presentation on Confirmation to a group of yawning young people with glazed over eyes. I thought that the church is missing a great opportunity to connect with its dwindling younger parishoners in not showing strong leadership on a very relevant, current and crucial subject.
We should all join Dr Tim Stephens in trying to help Pell see the light on this issue.
Kate Hook | 24 May 2011


When describing CO2 as a pollutant we mean that it is harmful at certain concentrations. Plenty of otherwise natural or naturally-produced substances are. Sulphur being an obvious example.

The increased toxicity of certain plants is directly attributable to rising CO2 concentrations which in turn are directly attributable to human activities in releasing the CO2. That is surely a process that can be described as pollution? Ecologists certainly speak of pollution being a substance that causes instability or discomfort to a species or ecosystem.

See further:
Tim Stephens | 24 May 2011

Goodness! Is it possible that Cardinal Pell's opposition to the position (on climate change) espoused by both John Paul II and Benedict XVI puts him into a similar category of defiant disobedience as that in which Bishop Bill Morris found himself?
Mary Maraz, Coogee | 25 May 2011

Dr Tim, your point is well made and agrees with the thrust of what I’m saying: on the broad definitions needed to indict CO2 as pollution that you’ve cited, it is no more or less so than any other substance in the universe. Further: virtually all plants and animals are polluters! In the end, this is not saying much. As Don Alhambra observes in ‘The Gondoliers’, “When everybody’s somebody, then no one’s anybody.” It’s well documented that increased levels of CO2 help some organisms to flourish even as this means some others are harmed. That’s what the Catalyst program showed. But no one in that report called CO2 a pollutant. And rightly so: to make a judgement, that the net effect on life on this planet of CO2 increases from present levels will be significantly negative, is a huge call that no­ one ­ to my knowledge ­ has attempted to justify. Moreover, scientists tell us that at very high levels of CO2 “pollution” (3000 ppm) for millions of years in the Mesozoic Era, a (much warmer) earth was teeming with life. And that if we diluted the atmospheric level of this “pollutant” to not much less than half (150 ppm) of the historically meagre amount it is today (380 ppm), all plant and most animal life would certainly cease. If we are to class anything on this earth as a non­-pollutant, CO2 would be a damn good candidate. Alongside water of course - which is a much more significant greenhouse gas "pollutant" than CO2! The link supplied doesn’t advance the argument. CO2 is labelled a “pollutant” by the U.S. Federal EPA because it supposedly causes harmful global warming. But this is the point which Cardinal Pell contests.
HH | 25 May 2011

Oxygen is vital to life.

Yet is harmful at certain concentrations.

(eg as doctors know, if given to premature babies, it can make them go blind. As scuba divers know, it can cause seizures at certain depths.)

Yet we would not describe oxygen as a pollutant.

Carbon dioxide is vital for life on our planet - green plants require it for survival.

Human beings exhale carbon dioxide, it is a necessary part of the breathing process.

Yet carbon dioxide, like oxygen, is harmful at certain concentrations.

The word 'pollutant' is being used to describe carbon dioxide in the debate on climate-change to elicit a particular response - the desire to eliminate it.

Water vapour is a greater contributor to the "greenhouse effect" than carbon dioxide.

We don't describe water vapour as a pollutant. You can however, drown in water.

The description of carbon dioxide as a pollutant can alienate otherwise interested people because it is a misleading label, (unless all gases and vapours necessary for the sustaining of life are so described, rendering it meaningless).

This is an important debate. So the terms matter.
Sophie | 26 May 2011

Dr. Stephens - Geographer, Parishioner, International Environmental LAWYER. I SEE NO MENTION OF HIS QUALIFICATIONS IN ENVIRONMENTAL SCIENCE. He is informed by others, as is Cardinal Pell.
Claude Rigney | 28 May 2011

The Obvious

Psalm 42: 10

Not the bleeding environment again groan
Warmer sceptics reaching after post-modern science.
Not the bleeding environment again intone
Consumers enshrined with every known appliance.
Not the bleeding environment again wheeze
Politicians nervous for their marginal seats.
Not the bleeding environment again please
Critics quail, tourists quip, journalists bleat.
Not the bleeding environment again say
Executives drilling down to seven-figure pay.
Not the bleeding environment again inveigh
Doctors and nurses come National Radiation Day.
Not the bleeding environment again! Crass!
Says the cardinal primping his red robes for Mass.

THE SONNETEER | 30 May 2011

Since the author considers ice cover to be the most visible evidence of warming, should he confess to Cardinal Pell that ice is extending over most of Antarctica and canoes once rowed north of the current ice cover in the Arctic?
David Bennett | 30 May 2011

Sophie, your post was excellent. To my mind it was a sound counter to Tim Stephen's claim that CO2 is a pollutant.
Patrick James | 01 June 2011

Several commenters have repeated or adverted to the sceptic mantra that the increases in atmospheric concentration of CO2 are not a problem because CO2 is 'harmless' except in very high concentrations. After all we have gone from just 280ppm of CO2 in the atmosphere in pre-industrial times to about 393ppm today. The problem with this argument is that CO2 is remarkably good at trapping heat. That's why the Earth is kept warm and this greenhouse effect has been accepted as basic science since the work of Arrhenius in the 1890s. And by the way the radiative effect of CO2 can be established on the lab bench - it is a basic physical property of the molecule. If you dispute that, well, I guess you could challenge just about everything, including gravity! Bob Beale in the Sydney Morning Herald today has a lovely piece explaining the point that relatively small changes in concentrations can have big effects. He draws an analogy with ozone (O3): 'For every 10 million molecules of air, a mere four are ozone, yet thankfully they repel about 97 per cent of the dangerous ultraviolet radiation from the sun. Believe it or not, these tiny amounts of special gases in the atmosphere make life possible on our planet: small changes in their concentration could also make life far more dangerous.' Read more:
Tim Stephens | 02 June 2011

Dr Tim, Your last post essentially says that, contra the “mantra” of the sceptics, CO2 is indeed harmful because increases in CO2 levels from this point on will result in catastrophic global warming. Here is what is not in debate between most sceptics and warmists. 1. The basic science of CO2 etc greenhouse effect since Arrhenius. 2. The possibility, in principle, of small changes having big effects. Here is what is in debate. 1. Whether the first order of CO2 induced global warming, as theorised by Arrhenius, will through positive feedback breach “tipping” points and thus trigger unstoppable global warming as the warmists claim. 2. And so, whether THIS particular small change in THIS substance will indeed have the claimed big effects. Cardinal Pell is one of many sceptics as to those touted trigger effects of increased CO2 levels. He may be right, he may be wrong. But how can one rationally criticize him (et al) for not embracing the universal labelling of CO2 as “harmful”, when he questions or rejects the theory that CO2 is in fact causing harm in this way? I’m no scientist. I’m uncertain as to whether CO2 increases will threaten mankind and this planet, or benefit both. But what will certainly doom mankind one way or another is a loss of the ability to reason carefully about important things.
HH | 06 June 2011

Dear HH,

I don't think anything is going to be resolved via the comments section here, but if you would like to follow up the published science I'd encourage you to do so.

The best place for this is The reason I say this is that it is not simply another blog containing all manner of opinion on climate change, it is a careful dissection of arguments of the kind that His Eminence makes by reference to the peer-reviewed publications in the field.

You can follow links to all of the relevant articles, read them, and work out for yourself whether you think climate sensitivity is nil or small or large, and whether there are 'tipping points' and when we are going to pass them.

And if you are interested in a terrific general overview, you can't really go pass Jim Hansen of NASA's talk in NZ last week which is now up on YouTube:

This is worth watching from beginning to end.

Best wishes,

Tim Stephens | 07 June 2011

Discussions with deniers are like bible discussions with fundamentalists to be avoided at all costs as a waste of time. You can never pin down their base parameters. The only reason that any credence is given to Cardinal Pell is his Church position. - the last I heard was that it was not recognised as a scientific qualification. If he was a truck driver he would deserve the same credence.
Patrick John McGee | 30 November 2012