The Nobel Prize (for propaganda)

Mankind pumping out trillions of gallons of oil in just over a century (and burning it) , that nature took billions of years to sequester has no effects.

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It is a fine line we tred between being widely understood and technically correct.

When one talks about phase changes and the heat released or absorbed when they occur, most people's eyes glaze over and they tune out. If one says that it takes less heat to boil alcohol than water, they seem to get it.

I don't really know how to deal with the fact that even most "educated" people don't have a solid grounding in math, chemistry and physics. A person can get a Ph.D. today and never even be exposed to the term "heat of vaporization," much less understand the implication of it in practical terms.

Hell, most people don't even have a feel for orders of magnitude - they bandy around millions, billions and trillions like they are about the same. They are just generic "big numbers" in most minds.

The sad result of this lack of well-rounded education among so-called educated people is they (and the people who follow them) are vulnerable to superstition based on emotion.

I'm amazed about how little the average guy knows about the "size" of things....I've asked smart people to guess the approximate size of the container that could hold all of the humans in the world, in cubic miles. The guess is always hundreds or thousands of cubic miles....The answer is a little more than a tenth of a cubic mile.

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LaRocha said:

How could we discuss any of those things? You don't believe there's any science being done by the world's climatologists and experts in the field. That a bunch of Internet jokers have uncovered the biggest hoax since Human evolution. You believe NOAA and NASA are government propaganda. Why would anyone want do do anything but play games with you?

The scientist you quoted, Beddington, is as political and as supportive of the theory of Anthropogenic Global Warming as it gets. He's the Chief Scientist in the British government. You either didn't read the article you posted, or you figured you had someone saying, "This is all shit science."

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The IPCC report states atmospheric lifetime of CO2) is 50-200 years (without defining the term 'lifetime'--it assumed this means residence time). The article rightly uses C12, C13, C14 isotopic ratios though not in much detail. Radon (Rn222) is also a proxy. Although there is disagreement on on the exact residence time in the scientific community (probably due to different variables), mass balance equations using isotopic ratios have a range is 3-25 years!!! THIS MEANS THERES A TOTAL TURNOVER OF CARBON EVERY 25 YEARS AT A MAXIMUM. I've cited 5 years in an earlier post and here is an article that corroborates this number http://www.greenworldtrust.org.uk/Science/Scientific/Segalstad.htm (see section 9) which means total atmospheric CO2 contributed by fossil fuels is 1.2%. The IPCC reports state it's 21%. In order to achieve 21%, with a residence time of 5 years, the CO2 resevoir would have to be 5 times larger than the atmosphere itself (Broeker et al., 1979: Fate of fossil fuel, carbon dioxide and the global carbon balance. Science, 206: 409-418.)

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Wait, so we don't thoroughly understand the connection between temperature increases and atmospheric water vapor? Yet, for decades, climate scientists and activists have been confidently asserting that water vapor is a strong positive feedback, an assertion which is essentially the cornerstone of the global warming theory? And all the while, they've been mocking as "flat-earthers" those who disagree with them? This is quite a shock. My whole weekend is ruined.

I refer you to Richard Lindzen, who, in 1992, wrote:

"The most important positive feedback in current models is due to water vapor. In all current models upper tropospheric (five to twelve kilometers) water vapor--the major greenhouse gas--increases as surface temperatures increase. Without that feedback, no current model would predict warming in excess of 1.7 degrees centigrade--regardless of any other factors. Unfortunately, the way current models handle factors such as clouds and water vapor is disturbingly arbitrary. In many instances the underlying physics is simply not known. In other instances there are identifiable errors. Even computational errors play a major role. Indeed, there is compelling evidence for all the known feedback factors to actually be negative. In that case, we would expect the warming response to carbon dioxide doubling alone to be diminished."

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The inability of climate science to admit that their understanding of the climate system is, at best, limited if not downright primitive is part of the problem. The exaggeration of human comprehension of climate has greatly damaged climate science's credibility.

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This is a thriller about codebreaking – not Napoleon's or Hitler's codes, but computer codes that generated a false signal to the world about runaway global warming. Like most codebreaking it was painfully slow but Montford keeps the drama pacy as the years pass, while he explains the intricacies in the plainest possible language. By military codebreaking, the likes of Scovell and Turing helped to change the course of history, and McIntyre and McKitrick should soon do the same, when the statistical fudges that misled the politicians become more widely known.

Nigel Calder
Former editor, New Scientist
co-author, The Chilling Stars

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While perusing some of the review comments to the IPCC's Fourth Assessment Report, I came across the contributions of Andrew Lacis ( http://www.giss.nasa.gov/staff/alacis.html ), a colleague of James Hansen's at GISS. Lacis's is not a name I've come across before but some of what he has to say about Chapter 9 of the IPCC's report is simply breathtaking.

Chapter 9 is possibly the most important one in the whole IPCC report - it's the one where they decide that global warming is manmade. This is the one where the headlines are made.

Remember, this guy is mainstream, not a sceptic, and you may need to remind yourself of that fact several times as you read through his comment ( http://pds.lib.harvard.edu/pds/view/7798293?n=17 ) on the executive summary of the chapter:

There is no scientific merit to be found in the Executive Summary. The presentation sounds like something put together by Greenpeace activists and their legal department. The points being made are made arbitrarily with legal sounding caveats without having established any foundation or basis in fact. The Executive Summary seems to be a political statement that is only designed to annoy greenhouse skeptics. Wasn't the IPCC Assessment Report intended to be a scientific document that would merit solid backing from the climate science community - instead of forcing many climate scientists into having to agree with greenhouse skeptic criticisms that this is indeed a report with a clear and obvious political agenda. Attribution can not happen until understanding has been clearly demonstrated. Once the facts of climate change have been established and understood, attribution will become self-evident to all. The Executive Summary as it stands is beyond redemption and should simply be deleted.​

I'm speechless. The chapter authors, however weren't. This was their reply (all of it):

Rejected. [Executive Summary] summarizes Ch 9, which is based on the peer reviewed literature.​

Simply astonishing. This is a consensus?

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At the end of January 2010 two distinguished scientific institutions shared headlines with Tony Blair over accusations of the dishonest and possibly illegal manipulation of information. Our ‘Himalayan glaciers melting by 2035′ of the Intergovernmental Panel on Climate Change is matched by his ‘dodgy dossier’ of Saddam’s fictitious subversions. We had the violations of the Freedom of Information Act at the University of East Anglia; he has the extraordinary 70-year gag rule on the David Kelly suicide file. There was ‘the debate is over’ on one side, and ‘WMD beyond doubt’ on the other. The parallels are significant and troubling, for on both sides they involve a betrayal of public trust.

Politics will doubtless survive, for it is not a fiduciary institution; but for science the dangers are real. Climategate is particularly significant because it cannot be blamed on the well-known malign influences from outside science, be they greedy corporations or an unscrupulous State. This scandal, and the resulting crisis, was created by people within science who can be presumed to have been acting with the best of intentions. In the event of a serious discrediting of the global-warming claims, public outrage would therefore be directed at the community of science itself, and (from within that community) at its leaders who were either ignorant or complicit until the scandal was blown open. If we are to understand Climategate, and move towards a restoration of trust, we should consider the structural features of the situation that fostered and nurtured the damaging practices. I believe that the ideas of Post-Normal Science (as developed by Silvio Funtowicz and myself) can help our understanding.

There are deep problems of the management of uncertainty in science in the policy domain, that will not be resolved by more elaborate quantification. In the gap between science and policy, the languages, their conventions and their implications are effectively incommensurable. It takes determination and skill for a scientist who is committed to social responsibility, to avoid becoming a ‘stealth advocate’ (in the terms of Roger Pielke Jr.). When the policy domain seems unwilling or unable to recognise plain and urgent truths about a problem, the contradictions between scientific probity and campaigning zeal become acute. It is a perennial problem for all policy-relevant science, and it seems to have happened on a significant scale in the case of climate science. The management of uncertainty and quality in such increasingly common situations is now an urgent task for the governance of science.

We can begin to see what went seriously wrong when we examine what the leading practitioners of this ‘evangelical science’ of global warming (thanks to Angela Wilkinson) took to be the plain and urgent truth in their case. This was not merely that there are signs of exceptional disturbance in the ecosphere due to human influence, nor even that the climate might well be changing more rapidly now than for a very long time. Rather, they propounded, as a proven fact, Anthropogenic Carbon-based Global Warming. There is little room for uncertainty in this thesis; it effectively needs hockey-stick behaviour in all indicators of global temperature, so that it is all due to industrialisation. Its iconic image is the steadily rising graph of CO2 concentrations over the past fifty years at the Mauna Loa volcano in Hawaii (with the implicit assumption that CO2 had always previously been at or below that starting level). Since CO2 has long been known to be a greenhouse gas, with scientific theories quantifying its effects, the scientific case for this dangerous trend could seem to be overwhelmingly simple, direct, and conclusive.

In retrospect, we can ask why this particular, really rather extreme view of the prospect, became the official one. It seems that several causes conspired. First, the early opposition to any claim of climate change was only partly scientific; the tactics of the opposing special interests were such as to induce the proponents to adopt a simple, forcefully argued position. Then, once the position was adopted, its proponents became invested in it, and attached to it, in all sorts of ways, institutional and personal. And I suspect that a simplified, even simplistic claim, was more comfortable for these scientists than one where complexity and uncertainty were acknowledged. It is not merely a case of the politicians and public needing a simple, unequivocal message. As Thomas Kuhn described ‘normal science’, which (as he said) nearly all scientists do all the time, it is puzzle-solving within an unquestioned framework or ‘paradigm’. Issues of uncertainty and quality are not prominent in ‘normal’ scientific training, and so they are less easily conceived and managed by its practitioners.

Now, as Kuhn saw, this ‘normal’ science has been enormously successful in enabling our unprecedented understanding and control of the world around us. But his analysis related to the sciences of the laboratory, and by extension the technologies that could reproduce stable and controllable external conditions for their working. Where the systems under study are complicated, complex or poorly understood, that ‘textbook’ style of investigation becomes less, sometimes much less, effective. The near-meltdown of the world’s financial system can be blamed partly on naïvely reductionist economics and misapplied simplistic statistics. The temptation among ‘normal’ scientists is to work as if their material is as simple as in the lab. If nothing else, that is the path to a steady stream of publications, on which a scientific career now so critically depends. The most obvious effect of this style is the proliferation of computer simulations, which give the appearance of solved puzzles even when neither data nor theory provide much support for the precision of their numerical outputs. Under such circumstances, a refined appreciation of uncertainty in results is inhibited, and even awareness of quality of workmanship can be atrophied.

In the course of the development of climate-change science, all sorts of loose ends were left unresolved and sometimes unattended. Even the most fundamental quantitative parameter of all, the forcing factor relating the increase in mean temperature to a doubling of CO2, lies somewhere between 1 and 3 degrees, and is thus uncertain to within a factor of 3. The precision (at about 2%) in the statements of the ‘safe limits’ of CO2 concentration, depending on calculations with this factor, is not easily justified. Also, the predictive power of the global temperature models has been shown to depend more on the ’story line’ than anything else, the end-of century increase in temperature ranging variously from a modest one degree to a catastrophic six. And the ‘hockey stick’ picture of the past, so crucial for the strict version of the climate change story, has run into increasingly severe problems. As an example, it relied totally on a small set of deeply uncertain tree-ring data for the Medieval period, to refute the historical evidence of a warming then; but it needed to discard that sort of data for recent decades, as they showed a sudden cooling from the 1960’s onwards! In the publication, the recent data from other sources were skilfully blended in so that the change was not obvious; that was the notorious ‘Nature trick’ of the CRU e-mails.

Even worse, for the warming case to have political effect, a mere global average rise in temperature was not compelling enough. So that people could appreciate the dangers, there needed to be predictions of future climate – or even weather – in the various regions of the world. Given the gross uncertainties in even the aggregated models, regional forecasts are really beyond the limits of science. And yet they have been provided, with various degrees of precision. Those announced by the IPCC have become the most explosive.

As all these anomalies and unsolved puzzles emerged, the neat, compelling picture became troubled and even confused. In Kuhn’s analysis, this would be the start of a ‘pre-revolutionary’ phase of normal science. But the political cause had been taken up by powerful advocates, like Al Gore. We found ourselves in another crusading ‘War’, like those on (non-alcoholic) Drugs and ‘Terror’. This new War, on Carbon, was equally simplistic, and equally prone to corruption and failure. Global warming science became the core element of this major worldwide campaign to save the planet. Any weakening of the scientific case would have amounted to a betrayal of the good cause, as well as a disruption of the growing research effort. All critics, even those who were full members of the scientific peer community, had to be derided and dismissed. As we learned from the CRU e-mails, they were not considered to be entitled to the normal courtesies of scientific sharing and debate. Requests for information were stalled, and as one witty blogger has put it, ‘peer review’ was replaced by ‘pal review’.

Even now, the catalogue of unscientific practices revealed in the mainstream media is very small in comparison to what is available on the blogosphere. Details of shoddy science and dirty tricks abound. By the end, the committed inner core were confessing to each other that global temperatures were falling, but it was far too late to change course. The final stage of corruption, cover-up, had taken hold. For the core scientists and the leaders of the scientific communities, as well as for nearly all the liberal media, ‘the debate was over’. Denying Climate Change received the same stigma as denying the Holocaust. Even the trenchant criticisms of the most egregious errors in the IPCC reports were kept ‘confidential’. And then came the e-mails.

We can understand the root cause of Climategate as a case of scientists constrained to attempt to do normal science in a post-normal situation. But climate change had never been a really ‘normal’ science, because the policy implications were always present and strong, even overwhelming. Indeed, if we look at the definition of ‘post-normal science’, we see how well it fits: facts uncertain,values in dispute, stakes high, and decisions urgent. In needing to treat Planet Earth like a textbook exercise, the climate scientists were forced to break the rules of scientific etiquette and ethics, and to play scientific power-politics in a way that inevitably became corrupt. The combination of non-critical ‘normal science’ with anti-critical ‘evangelical science’ was lethal. As in other ‘gate’ scandals, one incident served to pull a thread on a tissue of protective plausibilities and concealments, and eventually led to an unravelling. What was in the e-mails could be largely explained in terms of embattled scientists fighting off malicious interference; but the materials ready and waiting on the blogosphere provided a background, and that is what converted a very minor scandal to a catastrophe.

Consideration of those protective plausibilities can help to explain how the illusions could persist for so long until their sudden collapse. The scientists were all reputable, they published in leading peer-reviewed journals, and their case was itself highly plausible and worthy in a general way. Individual criticisms were, for the public and perhaps even for the broader scientific community, kept isolated and hence muffled and lacking in systematic significance. And who could have imagined that at its core so much of the science was unsound? The plausibility of the whole exercise was, as it were, bootstrapped. I myself was alerted to weaknesses in the case by some caveats in Sir David King’s book The Hot Topic; and I had heard of the hockey-stick affair. But even I was carried along by the bootstrapped plausibility, until the scandal broke. (I have benefited from the joint project on plausibility in science of colleagues in Oxford and at the Arizona State University).

Part of the historic significance of Climategate is that the scandal was so effectively and quickly exposed. Within a mere two months of the first reports in the mainstream media, the key East Anglia scientists and the Intergovernmental Panel on Climate Change were discredited. Even if only a fraction of their scientific claims were eventually refuted, their credibility as trustworthy scientists was lost. To explain how it all happened so quickly and decisively, we have the confluence of two developments, one social and the other technical. For the former, there is a lesson of Post-Normal Science, that we call the Extended Peer Community. In traditional ‘normal’ science, the peer community, performing the functions of quality-assurance and governance, is strictly confined to the researchers who share the paradigm. In the case of ‘professional consultancy’, the clients and/or sponsors also participate in governance. We have argued that in the case of Post-Normal Science, the ‘extended peer community’, including all affected by the policy being implemented, must be fully involved. Its particular contribution will depend on the nature of the core scientific problem, and also on the phase of investigation. Detailed technical work is a task for experts, but quality-control on even that work can be done by those with much broader expertise. And on issues like the definition of the problem itself, the selection of personnel, and crucially the ownership of the results, the extended peer community has full rights of participation. This principle is effectively acknowledged in many jurisdictions, and for many policy-related problems. The theory of Post-Normal Science goes beyond the official consensus in recognising ‘extended facts’, that might be local knowledge and values, as well as unoffficially obtained information.

The task of creating and involving the extended peer community (generally known as ‘participation’) has been recognised as difficult, with its own contradictions and pitfalls. It has grown haphazardly, with isolated successes and failures. Hitherto, critics of scientific matters have been relegated to a sort of samizdat world, exchanging private letters or writing books that can easily be ignored (as not being peer-reviewed) by the ruling establishment. This has generally been the fate of even the most distinguished and responsible climate-change critics, up to now. A well-known expert in uncertainty management, Jeroen van der Sluijs, explicitly condemned the ‘overselling of certainty’ and predicted the impending destruction of trust; but he received no more attention than did Nikolas Taleb in warning of the ‘fat tails’ in the probability distributions of securities that led to the Credit Crunch. A prominent climate scientist, Mike Hulme, provided a profound analysis in Why We Disagree About Climate Change, in terms of complexity and uncertainty. But since legitimate disagreement was deemed nonexistent, he too was ignored.

To have a political effect, the ‘extended peers’ of science have traditionally needed to operate largely by means of activist pressure-groups using the media to create public alarm. In this case, since the global warmers had captured the moral high ground, criticism has remained scattered and ineffective, except on the blogosphere. The position of Green activists is especially difficult, even tragic; they have been ‘extended peers’ who were co-opted into the ruling paradigm, which in retrospect can be seen as a decoy or diversion from the real, complex issues of sustainability, as shown by Mike Hulme. Now they must do some very serious re-thinking about their position and their role.

The importance of the new media of communications in mass politics, as in the various ‘rainbow revolutions’ is well attested. To understand how the power-politics of science have changed in the case of Climategate, we can take a story from the book Here Comes Everybody by Clay Shirkey. There were two incidents in the Boston U.S.A. diocese of the Roman Catholic Church, involving the shuffling of paeodophile priests around parishes. The first time, there was a criminal prosecution, with full exposure in the press, and then nothing happened. The second time, the outraged parents got on their cell phones and organised; and eventually Cardinal Archbishop Bernard Francis Law (who had started as a courageous cleric in the ‘60’s) had to leave for Rome in disgrace. The Climategate affair shows the importance of the new IT for science, as an empowerment of the extended peer community.

The well-known principle, ‘knowledge is power’ has its obverse, ‘ignorance is impotence’. And ignorance is maintained, or eventually overcome, by a variety of socio-technical means. With the invention of cheap printing on paper, the Bible could be widely read, and heretics became Reformers. The social activity of science as we know it expanded and grew through the age of printing. But knowledge was never entirely free, and the power-politics of scientific legitimacy remained quite stable for centuries. The practice of science has generally been restricted to a social elite and its occasional recruits, as it requires a prior academic education and a sufficiency of leisure and of material resources. With the new information technology, all that is changing rapidly. As we see from the ‘open source’ movement, many people play an active role in enjoyable technological development in the spare time that their job allows or even encourages. Moreover, all over IT there are blogs that exercise quality control on the industry’s productions. In this new knowledge industry, the workers can be as competent as the technicians and bosses. The new technologies of information enable the diffusion of scientific competence and the sharing of unofficial information, and hence give power to peer communities that are extended far beyond the Ph.D.s in the relevant subject-specialty. The most trenchant and effective critics of the ‘hockey stick’ statistics were a University-employed economist and a computer expert.

Like any other technology, IT is many-faceted. It is easily misused and abused, and much of the content of the blogosphere is trivial or worse. The right-wing political agendas of some climate sceptics, their bloggers and their backers, are quite well known. But to use their background or motivation as an excuse for ignoring their arguments, is a betrayal of science. The blogosphere interacts with other media of communication, in the public and scientific domains. Some parts are quite mainstream, others not. The Climategate blogosphere is as varied in quality as any other. Some leading scholars, like Roger Pielke, Jr. have had personal blogs for a long time. Some blogs are carefully monitored, have a large readership and are sampled by the mainstream media (such as the one on which this is posted, Wattsupwiththat.com). Others are less rigorous; but the same variation in quality can be found in the nominally peer-reviewed scientific literature. Keeping up with the blogosphere requires different skills from keeping up with traditional literature; it is most useful to find a summarising blog that fits one’s special interests, as well as a loyal correspondent, as (in my case) Roger ‘tallbloke’ Tattersall.

Some mainstream publications are now saying nice things about the blogosphere. Had such sentiments been expressed a while ago, the critical voices might have had a public hearing and the Climategate scandal might have been exposed before it became entrenched so disastrously. And now the critical blogosphere does not need to be patronised. Like any extension of political power, whether it be the right to believe, to protest, to vote, to form trades unions, or to be educated, it can lead to instabilities and abuses. But now the extended peer community has a technological base, and the power-politics of science will be different. I cannot predict how it will work out, but we can be confident that corruptions built on bootstrapped plausibility will be less likely in the future.

There is an important philosophical dimension to Climategate, a question of the relation of personal scientific ethics to objective scientific facts. The problem is created by the traditional image of science (as transmitted in scientific education) as ‘value-free’. The personal commitments to integrity, that are necessary for the maintenance of scientific quality, receive no mention in the dominant philosophy of science. Kuhn’s disenchanted picture of science was so troubling to the idealists (as Popper) because in his ‘normal’ science criticism had hardly any role. For Kuhn, even the Mertonian principles of ethical behaviour were effectively dismissed as irrelevant. Was this situation truly ‘normal’ – meaning either average or (worse) appropriate? The examples of shoddy science exposed by the Climategate convey a troubling impression. From the record, it appears that in this case, criticism and a sense of probity needed to be injected into the system by the extended peer community from the (mainly) external blogosphere.

The total assurance of the mainstream scientists in their own correctness and in the intellectual and moral defects of their critics, is now in retrospect perceived as arrogance. For their spokespersons to continue to make light of the damage to the scientific case, and to ignore the ethical dimension of Climategate, is to risk public outrage at a perceived unreformed arrogance. If there is a continuing stream of ever more detailed revelations, originating in the blogosphere but now being brought to a broader public, then the credibility of the established scientific authorities will continue to erode. Do we face the prospect of the IPCC reports being totally dismissed as just more dodgy dossiers, and of hitherto trusted scientists being accused of negligence or worse? There will be those who with their own motives will be promoting such a picture. How can it be refuted?

And what about the issue itself? Are we really experiencing Anthropogenic Carbon-based Global Warming? If the public loses faith in that claim, then the situation of science in our society will be altered for the worse. There is very unlikely to be a crucial experience that either confirms or refutes the claim; the post-normal situation is just too complex. The consensus is likely to depend on how much trust can still be put in science. The whole vast edifice of policy commitments for Carbon reduction, with their many policy prescriptions and quite totalitarian moral exhortations, will be at risk of public rejection. What sort of chaos would then result? The consequences for science in our civilisation would be extraordinary.

To the extent that the improved management of uncertainty and ignorance can remedy the situation, some useful tools are at hand. In the Netherlands, scholars and scientists have developed ‘Knowledge Quality Assessment’ methodologies for characterising uncertainty in ways that convey the richness of the phenomenon while still performing well as robust tools of analysis and communication. Elsewhere, scholars are exploring methods for managing disagreement among scientists, so that such post-normal issues do not need to become so disastrously polarised. A distinguished scholar, Sheila Jasanoff, has called for a culture of humility among scientists, itself a radical move towards a vision of a non-violent science. Scientists who have been forced to work on the blogosphere have had the invaluable experience of exclusion and oppression; that could make it easier for them to accept that something is seriously wrong and then to engage in the challenging moral adventures of dealing with uncertainty and ignorance. The new technologies of communications are revolutionising knowledge and power in many areas. The extended peer community of science on the blogosphere will be playing its part in that process. Let dialogue commence!

——————-

My thanks to numerous friends and colleagues for their loyal assistance through all the drafts of this essay. The final review at a seminar at the Institute of Science, Innovation and Society at Oxford University was very valuable, particularly the intervention from ‘the man in the bus queue’.

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A - Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?

Phil Jones: An initial point to make is that in the responses to these questions I've assumed that when you talk about the global temperature record, you mean the record that combines the estimates from land regions with those from the marine regions of the world. CRU produces the land component, with the Met Office Hadley Centre producing the marine component.

Temperature data for the period 1860-1880 are more uncertain, because of sparser coverage, than for later periods in the 20th Century. The 1860-1880 period is also only 21 years in length. As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different (see numbers below).

I have also included the trend over the period 1975 to 2009, which has a very similar trend to the period 1975-1998.

So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other...

*****​

B - Do you agree that from 1995 to the present there has been no statistically-significant global warming

Phil Jones: Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.

*****​

D - Do you agree that natural influences could have contributed significantly to the global warming observed from 1975-1998, and, if so, please could you specify each natural influence and express its radiative forcing over the period in Watts per square metre.

Phil Jones:This area is slightly outside my area of expertise. When considering changes over this period we need to consider all possible factors (so human and natural influences as well as natural internal variability of the climate system). Natural influences (from volcanoes and the Sun) over this period could have contributed to the change over this period. Volcanic influences from the two large eruptions (El Chichon in 1982 and Pinatubo in 1991) would exert a negative influence. Solar influence was about flat over this period. Combining only these two natural influences, therefore, we might have expected some cooling over this period.

*****​

G - There is a debate over whether the Medieval Warm Period (MWP) was global or not. If it were to be conclusively shown that it was a global phenomenon, would you accept that this would undermine the premise that mean surface atmospheric temperatures during the latter part of the 20th Century were unprecedented?

Phil Jones: There is much debate over whether the Medieval Warm Period was global in extent or not. The MWP is most clearly expressed in parts of North America, the North Atlantic and Europe and parts of Asia. For it to be global in extent the MWP would need to be seen clearly in more records from the tropical regions and the Southern Hemisphere. There are very few palaeoclimatic records for these latter two regions.

Of course, if the MWP was shown to be global in extent and as warm or warmer than today (based on an equivalent coverage over the NH and SH) then obviously the late-20th century warmth would not be unprecedented. On the other hand, if the MWP was global, but was less warm that today, then current warmth would be unprecedented.

We know from the instrumental temperature record that the two hemispheres do not always follow one another. We cannot, therefore, make the assumption that temperatures in the global average will be similar to those in the northern hemisphere.

*****​

N - When scientists say "the debate on climate change is over", what exactly do they mean - and what don't they mean?

Phil Jones: It would be supposition on my behalf to know whether all scientists who say the debate is over are saying that for the same reason. I don't believe the vast majority of climate scientists think this. This is not my view. There is still much that needs to be undertaken to reduce uncertainties, not just for the future, but for the instrumental (and especially the palaeoclimatic) past as well.

*****​

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