Tag: Hockey Stick

AGW certainty, Part Two

Continuing the examination of two views on AGW.

Readers will recall that this post opened yesterday.  That Part One closed with Martin writing this:

Martin Lack

Much of what Oakwood writes is an attack upon the Hockey Stick graph of palaeoclimatic temperature reconstructions first produced in 1998 (MBH98).

However, the fatal flaws in Oakwood’s scepticism regarding MBH98 are as follows:

  1. MBH98 has been validated by at least 14 other reconstructions (as cited in IPCC AR4 in 2007) using a wide variety of other proxy data(see Wikipedia for relevant links)
  2. Hockey Stick-shaped graphs turn up in reconstructions of CO2 levels and temperature – now going back over thousands of years – because they are not ‘statistical noise’ –
  3. Arguments about splicing instrumental data onto proxy data only serve to challenge the extent to which the speed of late 20th Century warming is unprecedented.
  4. Such arguments do not invalidate the conclusion that it is now almost certainly warmer than it has been at any time since the last Ice Age (i.e. a period of relative climate and sea level stability that has made agriculture, urbanisation and civilisation possible).

However, this is no reason for us to be complacent because, as Oakwood must know, the 50 to 100 metres of sea level rise that will be caused by the melting of terrestrial ice sheets will necessitate the mass migration of millions of people. This makes his concerns about current poverty and starvation (i.e. the main reason he eventually cites for not believing action is yet necessary) look very trivial indeed.

So continuing ….


The argument that the ‘divergence problem’ does not bring into question proxy studies is just one example of supposed ‘settled’ evidence in the case for AGW. There are others which collectively bring down the case to one of opinion.

Martin Lack

After a lengthy attempt to assert that the “hide the decline” controversy was or is significant, Oakwood eventually moves onto attack the significance of MBH98; and to claim that ACD is no more than a matter of opinion. It is only possible to reach this conclusion by dismissing the majority of climate scientists as being stupid, sloppy, or sinister.


Here are a few others:

  • Mann et al’s original hockey stick (1998) (as well as a number of other studies) shows an unprecedented temperature rise in the first half of the 20th century, a temperature change that most climate scientists believe can be explained by natural phenomena, such as the Sun (while failing to reproduce the man-made rise in the 2nd half of the century, due to the divergence problem explained above).

Martin Lack

However, Climategate and, more especially Climategate 2.0 merely served to demonstrate how deliberate and organised are the attempts to discredit climate science and derail international attempts to tackle the ACD problem.


Thus, we are expected to believe there was both an unprecedented NATURAL temperature rise and unprecedented MAN-MADE rise in the same century. Not impossible, but statistically highly unlikely.

Martin Lack

Oakwood suggests that assertions about early 20th Century warming are statistically highly unlikely (i.e. that climate scientists are stupid to make them). However, the real statistically highly unlikely suggestion is that 30 years of monthly average temperatures exceeding their long-term average values could be a consequence of natural variation. Unlike early 20th Century warming, this is definitely not capable of being explained by natural causes (such as cyclical solar activity or random volcanic eruptions).


  • The ‘record’ (in just 35 years) of minimum summer ice in the Arctic is repeatedly presented as evidence for impending doom. However, the record MAXIMUM ice cover in the ANTarctic, at the same time, is dismissed with ‘we have another explanation for that’.

Martin Lack

Trying to shift the focus away from the accelerating rate of ice loss in the Arctic is very lame indeed. The Arctic is surrounded by land and (now) increasing amounts of warming water. The reasons for the ice loss are well understood and it is happening faster than was predicted even 5 years ago. The Antarctic is surrounded by a huge expanse of cold ocean and is also being kept cold by the human caused hole in the ozone layer. The reasons why its ice is not melting so fast are therefore also well understood. In addition, it should be noted that the Antarctic Peninsula is the fastest warming place in the southern hemisphere.


  • Whatever the weather, blame global warming. A few years ago, milder winters and earlier springs in the UK were hailed as evidence of AGW. But now we get lots of snow, and appalling spring, cooler summers, etc, and guess what, its due to global warming.
  • Hot/dry weather and floods around the world are routinely highlighted as ‘more evidence’ whereas as cold weather extremes and records are dismissed as ‘just natural variation’ – again, and again and again.

Martin Lack

Oakwood‘s remarks about extreme events are also very misleading. The number of records being broken for hot and/or dry events is many times greater than the number of records being broken for cold and/or wet events. As Hansen et al explained last year, in their review of historical data for the last five decades, natural variability does not explain the steady shift in average temperatures and the broadening of the range of conditions experienced in any one place.

I really can’t believe that Oakwood is so parochial in his outlook that he dares to mention the cold weather the UK has experienced recently. We may have had the coldest Spring for 50 years, but, that does not change the fact that global average temperatures are still the highest ever in recorded history. Furthermore, it does not change the fact that the analysis of Hansen et al (2012) continues to be validated by events such as those in Central Europe at the moment – where 1 in 100 year flood events have recurred after only 10 years. Not impossible – just statistically highly unlikely.


Those who highlight the lack of rising temperature for the past 10-15 years are routinely dismissed as deniers and liars. We’re told, ‘but the last decade is the warmest in a 100 years’. No-one disputes that. Given the world warmed by 0.8 degC in 100 years, that’s perfectly reasonable, and is not a defence against the fact that warming has at least paused.

  • We’re told: ‘but the heat is going into the ice caps and the deep oceans and atmospheric heat is just a small percentage of the total’, How convenient. In the 1980s and 1990s, atmospheric temperature was enough for ‘proof’ of serious AGW. We didn’t hear anything about ocean heat then. No-one suggested that perhaps the warming was due to a release of previously ‘hidden’ ocean heat. Or that we shouldn’t read too much into a small atmospheric temperature rise.
  • We see again and again, whatever happens, whatever the data show, the theory is revised to ‘show’ that nothing has changed. This is simply not plausible science.
  • We’re told, the physics of CO2-induced global warming is just that, ‘physics’, and we can’t change that however much we dispute it. No-one disputes the physics. But, the atmosphere (believe it or not) is very complicated. We have the physics that says aerosols reflect the Sun’s heat, that clouds may increase and also reflect more heat. We now hear the relationships with the oceans is very important (which we didn’t hear before). Thus the debate is not about the reality of the CO2-global warming physics. Its about the sensitivity of the system and which physical phenomena will dominate.

Martin Lack

Given the massive inertia in the climate system (which guarantees decades of future temperature rise even if CO2 emissions were completely halted today), there is no reason for us to be complacent about the fact that we have only seen a rise of 0.8C since the Industrial Revolution. The scientific consensus remains that equilibrium climate sensitivity is somewhere in excess of 2C and that such a rise in temperature will not be good for the vast majority of life on Earth. On the evidence of the ACD that we are already experiencing, I think there is very good reason to agree with that conclusion.

Again, I am astonished that Oakwood even dares to mention the ‘global warming has stopped’ canard. This misconception has been debunked so many times; there are even debates about who has written written the best rebuttals.  Here is a summary: Whilst surface warming may have paused, the warming of the ocean (which is driving the increased frequency of extreme weather events of all kinds) has continued. Given that oceans cover two thirds of the Earth’s surface, is this something really worth arguing about?

Climate scientists are therefore not changing their story to accommodate inconvenient new data. Only climate change sceptics do that. The only implausible science on offer today is that which seeks to explain all the data without acknowledging that CO2 is the main driver. Sure, CO2 does not explain everything but, you cannot explain all the data unless the primacy of CO2 is accepted.


Some will respond: ‘but all of these arguments have been debunked many times’. All they really mean is another opinion or speculation has been given by an AGW believer. Nothing wrong with these, but don’t claim they represent settled science.

Martin Lack

However, I should like to re-iterate the importance of the recently-published results of investigations at a lake in the NE of Arctic Russia. What this new 3.6 million year continuous palaeoclimatic record tells us is that current warmth is not unprecedented (if you go back to an era in which humans did not exist – 400 or 1,100 thousand years ago). This demonstrates that good scientists do not change their story when they get unexpected results.


I have no problem with scientists believing in AGW and believing it a serious threat. But when so much of their case is based on weak arguments, I do have a problem with claiming the case is ‘settled’ and that anyone who questions or challenges it is a liar, denier, conspiracy theorist, etc.

Both sides of the debate have their extremists and nutters. My interest is in the rational middle ground. To suggest an ‘eccentric’ like Christopher Monckton is ‘typical’ of all AGW-sceptics is just like claiming all Conservative voters are fascist and all Labour voters communist. It has no place in informed and educated debate.

Martin Lack

Oakwood claims arguments for concern over ACD are “weak” but, in making this assertion, the only information he has referred to is very much out-of-date (such as IPCC AR4 in 2007). Oakwood moves on to discuss unhelpful labels such as “liar” and “denier”.

I do not think I have ever suggested that anyone who professes to be ‘sceptical’ is lying. However, I do think that, just like the tobacco executives whose ‘modus operandi’ they are copying, the executives of fossil fuel companies know more than they care to admit. There is also a great deal of evidence to indicate that climate change ‘scepticism’ is in fact being driven by unscientific economists aided in their anti-science cause by a handful of friendly scientists who tell them what they want to hear. This is not scepticism, it is ideological prejudice.


The term “denier” was introduced with the intention of associating AGW-sceptics with Holocaust Deniers. That is to say, AGW-sceptics are putting millions of lives at risk through their lies and ignorance. Given the weakness of the AGW case, the use of the labels ‘denier’, ‘deny’, denial’ seems to represent an insult to every victim of the Holocaust.

Martin Lack

I agree that use of the term ‘denier’ is generally not helpful, but, given all the evidence that conflicts with their position, I do think that those who remain ‘sceptical’ about the primary cause of ongoing climate change are being irrational. If your beliefs require you to dismiss any and all evidence that conflicts with them, that is not scepticism, it is wilful blindness; it is what Young Earth Creationists have to do in order to protect themselves from wicked and ungodly scientific ideas.

Therefore, even if Oakwood does not do it, many who are ‘sceptical’ do rely upon conspiracy theories to dismiss all the evidence that conflicts with their beliefs. This includes dismissing most scientists as stupid, sloppy or sinister.


And why is it not time to act now? I am an environmentalist and see many environmental and social problems that need addressing. In particular, the need for ‘sustainability’ in all we do. There remain millions dying each year from such things as malnutrition, lack of safe drinking water, malaria, etc.

These are hard facts with zero room for any doubt. Given the weakness in the AGW-case, it is not a priority. I see some benefits in acting. For example, in many cases a reduction in CO2 emissions leads to much improved energy-efficiency, and less pollution. However, the case is not made for diverting money and effort from the more immediate priorities, covering pristine countryside in wind farms to satisfy urban energy demands, or using more biofuels at the expense of more hunger.

Martin Lack

Having wasted so much time trying to falsify MBH98, Oakwood finally gets round to the important bit of my question: Why does he think the time to act has not yet arrived?

Failing to address the point that a wide range of industrial, political and economic organisations now agree that it is time to act, Oakwood opts instead to simply re-state his belief that attempts to mitigate the ACD problem will do more harm than good. All the evidence I have seen suggests that he is mistaken. To-date, I think the most compelling evidence is that contained in the IIED’s 2009 report , ‘Assessing the costs of Adaptation to Climate Change: A review of UNFCCC and other recent estimates’ (PDF available here), which begins with the following very sobering executive summary:

Several recent studies have reported adaptation costs for climate change, including for developing countries. They have similar-sized estimates and have been influential in discussions on this issue.

However, the studies have a number of deficiencies which need to be transparent and addressed more systematically in the future. A re-assessment of the UNFCCC estimates for 2030 suggests that they are likely to be substantial under-estimates. The purpose of this report is to illustrate the uncertainties in these estimates rather than to develop new cost estimates, which is a much larger task than can be accomplished here.

The main reasons for under-estimation are that: (i) some sectors have not been included in an assessment of cost (e.g. ecosystems, energy, manufacturing, retailing, and tourism); (ii) some of those sectors which have been included have been only partially covered; and (iii) the additional costs of adaptation have sometimes been calculated as ‘climate mark-ups’ against low levels of assumed investment. In some parts of the world low levels of investment have led to a current adaptation deficit, and this deficit will need to be made good by full funding of development, without which the funding for adaptation will be insufficient. Residual damages also need to be evaluated and reported because not all damages can be avoided due to technical and economic constraints.

There is an urgent need for more detailed assessments of these costs, including case studies of costs of adaptation in specific places and sectors.


Thus, belief in AGW is not a simple moral argument which some would want to believe – good vs evil, or capitalist vs environmentalist, etc.

Martin Lack

Oakwood says he does not think this is a good-vs- evil or a capitalist-vs- environmentalist issue. I would agree. However:

  • I am not the one who is allowing my political beliefs to prejudice my approach to the science;
  • I am not the one who is accusing most scientists of being stupid, sloppy or sinister in order to dismiss what they are telling me; and
  • I am not the one changing my story or my preferred argument whenever something I have formerly relied upon is shown to be unreasonable.

Although it is a shame that he is part of a minority within the UK’s current Coalition Government, I will conclude by quoting from a recent speech by the Secretary of State for Energy and Climate Change, Edward Davey:

Of course there will always be uncertainties within climate science and the need for research to continue… We make progress by building on what we know, and questioning what we don’t. But some sections of the press are giving an uncritical campaigning platform to individuals and lobby groups who reject outright the fact that climate change is a result of human activity. Some who even deny the reality of climate change itself… By selectively misreading the evidence, they seek to suggest that climate change has stopped so we can all relax and burn all the dirty fuel we want without a care…

Oakwood says he opposes action to curb ACD because there are bigger problems we need to solve. If this were likely to be true, it would be an admirable position to take. Unfortunately, the bulk of the evidence suggests that ACD is a problem unlike any other and, unless we make serious attempts to minimise it, its consequences will dwarf all other problems we face.

This is because basic physics tells us that allowing the Earth to warm up will cause terrestrial ice to melt and sea levels to rise. It was predicted and it is now happening. The time to act to stop it is now. Millions of people cannot and will not adapt to having their land and their cities submerged under water.


Well I think that the agreement of Oakwood and Martin to set out their positions is fabulous and very worthy.

If readers will forgive me, tomorrow I will offer my own personal reflections on what has been offered by Martin and Oakwood today and yesterday.

Dr. Michael Mann

A review of Michael Mann’s new book The Hockey Stick and the Climate Wars: Dispatches from the Front Lines.

I’m republishing in full a recent Post on Kate’s fabulous blogsite Climate Change.  As a degree student, Kate is a fantastic representative of the generation that is going to have to deal in full with all the crap that my generation (born 1944) has brought about!  Learn more about her here.  Anything that can spread the word to those, especially in my age group, that are climate change denialists is no bad thing.

The Hockey Stick and the Climate Wars

February 22, 2012 by climatesight

Available from Columbia Press

Throughout all the years of public disputes about climate change, arguably no scientist has taken as much flak as Dr. Michael Mann. This mild-mannered paleoclimatologist is frequently accused of fraud, incompetence, scientific malpractice, Communism, and orchestrating a New World Order. These charges have been proven baseless time and time again, but the accusations continue. Dr. Mann’s research on climate change is inconvenient for those who wish to deny that current global temperatures are unusual, so he has become the bulls-eye target in a fierce game of “shoot the messenger”. In “The Hockey Stick and the Climate Wars: Dispatches from the Front Lines”, a memoir of his experiences, Michael Mann finally speaks out.

The story begins quite harmlessly: an account of how he became a scientist, from childhood curiosity to graduate work in theoretical physics to choosing climate science on a whim out of the university course calendar. For those who have followed Dr. Mann’s research over the years, there is some great backstory – how he met his coauthors Ray Bradley and Malcolm Hughes, the formation of the IPCC TAR chapter about paleoclimate, and how the RealClimate blog operates. This book also filled in some more technical gaps in my understanding with a reasonably accessible explanation of principal component ananlysis, a summary of millennial paleoclimate research before 1998, and an explanation of exactly how Mann, Bradley and Hughes’ 2008 paper built on their previous work.

Dr. Mann’s 1998 paper – the “hockey stick” – was a breakthrough because it was the first millennial reconstruction of temperature that had global coverage and an annual resolution. He considered the recent dramatic rise in temperatures to be the least interesting part of their work, because it was already known from instrumental data, but that part of the paper got the most public attention.

It seems odd for a scientist to downplay the importance of his own work, but that’s what Dr. Mann does: he stresses that, without the hockey stick, the case for climate change wouldn’t be any weaker. Unfortunately, his work was overemphasized on all sides. It was never his idea to display the hockey stick graph so prominently in the IPCC TAR, or for activists to publicize his results the way they did. Soon the hockey stick became the holy grail of graphs for contrarians to destroy. As Ben Santer says, “There are people who believe that if they can bring down Mike Mann, they can bring down the IPCC,” and the entire field of climate science as a result.

Michael Mann is an eloquent writer, and does a fabulous job of building up tension. Most readers will know that he was the target of countless attacks from climate change deniers, but he withholds these experiences until halfway through the book, choosing instead to present more context to the story. The narrative keeps you on your toes, though, with frequent allusions to future events.

Then, when the full story comes out, it hits hard. Death threats, and a letter full of suspicious white powder. Lobby groups organizing student rallies against Mann on his own campus, and publishing daily attack ads in the campus newspaper. Discovering that his photo was posted as a “target” on a neo-Nazi website that insisted climate change was a Jewish conspiracy. A state politician from the education committee threatening to cut off funding to the entire university until they fired Mann.

Throughout these attacks, Dr. Mann consistently found trails to the energy industry-funded Scaife Foundation. However, I think he needs to be a bit more careful when he talks about the links between oil companies and climate change denial – the relationship is well-known, but it’s easy to come off sounding like a conspiracy theorist. Naomi Oreskes does a better job of communicating this area, in my opinion.

Despite his experiences, Michael Mann seems optimistic, and manages to end the book on a hopeful note about improvements in climate science communication. He is remarkably well-adjusted to the attacks against him, and seems willing to sacrifice his reputation for the greater good. “I can continue to live with the cynical assaults against my integrity and character by the corporate-funded denial machine,” he writes. “What I could not live with is knowing that I stood by silently as my fellow human beings, confused and misled by industry-funded propaganda, were unwittingly led down a tragic path that would mortgage future generations.”

“The Hockey Stick and the Climate Wars” leaves me with a tremendous empathy for Dr. Mann and all that he has gone through, as well as a far better understanding of the shouting match that dominates certain areas of the Internet and the media. It is among the best-written books on climate science I have read, and I would highly recommend it to all scientists and science enthusiasts.

“The Hockey Stick and the Climate Wars” will be released on March 6th, and the Kindle version is already available.