IPCC Technical Assessment Report 5 – Thesis 2

Thesis: That the discussion of sea level rise in IPCC TAR4 has much to recommend as a model for other topics.

Those of you who have already seen our first thesis, on global temperatures, may have got the impression that we were out to ‘get’ the IPCC. This is not the case. We are self-financed and have no agenda. As we say on our Home Page: “We are trying to prove only one thing: rational debate is possible when participants have access to the facts.”

In TAR4 the increase in sea level is presented in the following graph.

This graph appears as Figure 3 in the Summary for Policy Makers and elsewhere (We have extracted the sea levels from a compound graph which also showed Global Average Temperatures and Northern Hemisphere snow cover). It combines levels from tide gauges (circular dots) and satellite measurements (the red line).

In the summary the accompanying text says: “Global average sea level rose at an average rate of 1.8 [1.3 to 2.3] mm per year over 1961 to 2003. The rate was faster over 1993 to 2003: about 3.1 [2.4 to 3.8] mm per year. Whether the faster rate for 1993 to 2003 reflects decadal variability or an increase in the longer term trend is unclear.” Similar words appear in the Technical Summary and the Synthesis report. What is commendable in this case is that even in the condensed Summary for Policy Makers there is no attempt to attach a high level of significance to the higher rate of sea level rise for the ten years preceding the preparation of the report.

The Technical Summary also states (Paragraph 3.3.3): “The tide gauge record indicates that faster rates similar to that observed in 1993 to 2003 have occurred in other decades since 1950.” This is supported by the following figure in Chapter 5 of the main report.

This contrasts markedly to the global temperature graph we discussed in the previous ‘thesis’. (http://www.climatedata.info/Discussions/Discussions/opinions.php?id=5404421343497121129 ).

There are two areas where the increase could be presented in a wider context in TAR5.

Firstly since TAR4 was written there is more evidence of sea level changes in the last couple of thousand years.

The blue crosses represent relative sea level rise for Vidarholmi in Iceland as calculated by Gehrels et al. No adjustment has been made for post glacial rebound but this is unlikely to have varied substantially over the period of the estimates. The figure before 100 AD may have been modified by compression in the salt marsh sampling area but even so the levels after that date suggest that recent rates of rise are by no means extraordinary.

The green circles show estimates of sea level on the coast of Israel calculated by Sivan and Toker. They are based on archaeological evidence from different broadly defined time periods (e.g. Hellenic or Crusader). The dating and levels are not given to a high degree of accuracy but also suggest that rapid sea level changes might have occurred in the past.

The red line, provided for comparison, is the increase since 1702 based on tide gauges by Jevrejeva et al. This confirms that the rate of sea level increase accelerated around 200 years ago and is not a recent phenomenon.

The second point is that in the previous interglacial sea levels were about 6 m higher than they are today and in other interglacial periods levels were from 3 m to 20 m higher. It is therefore possible than in coming centuries many coastal locations on earth might experience sea level rises of the same order of magnitude as those estimated by Sivan and Toker. That said there are many coastal cities in the world, such as Marseilles, Akko (Acre) and Naples, which existed well before the start of the present era and which have adapted to sea level changes.

IPCC TAR5: The TAR4 dealt with sea level changes accurately and in a responsible way. However the IPCC TAR5 could be improved by expanding information on the context of the projected level changes.

References:
Gehrels et al., Rapid sea-level rise in the North Atlantic Ocean since the first half of the nineteenth century. The Holocene 2006; 16; 949

Shivan and Toker, The Sea’s ups and downs. http://newmedia-eng.haifa.ac.il/?p=2330

Jevrejeva, S., J.C. Moore, A. Grinsted and P.L. Woodworth. 2008. Recent global sea level acceleration started over 200 years ago?, Geophysical Research Letters, 35

IPCC Technical Assessment Report 5 – Introduction

At the start of 2010 the IPCC attracted a lot of criticism for three projected climate change impacts which were poorly supported. These were that Himalayan glaciers might disappear by 2035, that African agricultural yields could fall by 50% and that 40% of the Amazonian rain-forest could react drastically to changes in precipitation. In each case the source of the claim was speculative and lacking sound evidence. The IPCC’s response was that in such a major series of documents it was well nigh impossible to avoid a few mistakes. To some extent this is true but the fact the errors all erred on the side of exaggerating the effects of climate change says much about the IPCC’s lack of balance.

We believe however that there are more serious criticisms which can be leveled against the IPCC.

Science is only as good as its data and in many cases the data presented by the IPCC tell only part of the story.

Since we are criticising the IPCC we should make out own position clear. So where do we stand? We believe that the science and data show unequivocally that temperatures today are higher than would have been case were it not for greenhouse gases emitted by human activity. On the other hand we do not believe that the more extreme forecasts of increased temperatures and their impact have been proven. We also believe that there are good reasons for reducing use of fossil fuels, of which effect on the climate is but one.

We also believe that climate modelling is important for the future. In the past, design of anything affected by weather, urban drainage or water supply for example, has been based on a statistical analysis of past data. It is now clear that a fundamental assumption of such analysis, that the events analysed are independent of each other, is invalid. To be able to predict natural and anthropogenic changes in climate should become the new paradigm for engineering design.

Our position, and that of those who have studied the science and share our views, is similar to that of Martin Luther, the 15th century reformer. He was, and remained all his life, a Christian but he thought that the activities and excesses of the Roman Catholic Church at that time were acting against the faith he accepted. We believe that there is a powerful analogy with the IPCC at the present time. Its performance is such that far from leading the population to accept their assertion that unless radical and immediate action is taking the world will suffer gravely they, by bias and distortion in their arguments, have left many people refusing to accept that humans have any influence on the climate.

Martin Luther put his case by pinning 95 Theses to the door of a church (today he would probably have been a blogger). What we are going to do is to publish a series of ‘theses’ where we highlight some aspects of the IPCC Technical Assessment Report of 2007 (TAR4) which could be improved in the next report (TAR5).

There remains one important question: Why should you believe us? The answer is you won’t have to. For reach of our theses we will give chapter and verse on the section of IPCC TAR4 we are commenting on and the source of the data we use to propose improvements.

Ian McEwan: Solar

This book has two features which differentiate it from the other books reviewed here: it is a novel and relatively unbiased on the topic of climate change.

Ian McEwan is one of Britain’s leading novelists. In interviews he says that he accepts the scientific view that climate change is taking place as a result of human activity. Some newspapers also reported that he had delayed publication of ‘Solar’ until after the Framework Convention on Climate Change Meeting in Copenhagen. From what I had read of his earlier novels I was expecting this novel to contain much wailing and gnashing of teeth but I was wrong. On the author’s web site the novel is described as “an engrossing and satirical novel which focuses on climate change”. I agree with that.

The main character, Michael Beard, won a Nobel Prize in Physics as a young man but he is now in his 50s treading water intellectually and trading on his reputation. He gives lectures and decorates various committees. Despite his unprepossessing appearance, baldness and excessive girth he is a serial husband and philanderer.

One of his appointments is as the one-day-week, figure-head, chief of a government initiative to tackle global warming. Initially showing only lukewarm interest in his sinecure, a combination of circumstances leads him to an awareness that photo-electrical interactions, his own area of expertise, could provide the ideal solution to clean, cheap, carbon-free energy. The book has a few factoids, which I have not checked, which underline his idea. A kilogram of gasoline contains 13,000 watt hours of electricity but the best batteries only store 300 watts hours per kilo. In other words, alternative energy sources have to compete with gasoline’s weight/energy ratio and avoid electrical storage. The third factoid is that the hydrogen in one litre of water has three times the energy of a litre of gasoline. Since hydrogen can be stored, unlocking it from water could provide the ideal clean source.

His route to this realisation is not straightforward. He is invited to join a group of artists concerned with climate change in a ship north (but only just) of the Arctic Circle which he is assured will be “toastily-heated”. One of the book’s great comic moments is when outside of the ship he stops to satisfy the needs of nature and discovers that at very low temperatures flesh sticks to metal zips. The irony of living in comfort, building ice-sculptures and riding snowmobiles to see vanishing glaciers as a protest against climate change is not lost on him.

While head of the government alternative energy centre, Beard decides to back a helical wind turbine for use on the roofs of private homes. The initial enthusiasm is soon worn down by health-and-safety concerns, current conversion and other problems which take teams of well-meaning but unproductive experts to examine in long and expensive detail.

As Beard's disorganised personal life impacts on his professional life, the invitations to lecture and to sit on boards become fewer and fewer. He starts to develop the idea of clean energy from water. To get development money he delivers a speech that Al Gore would be proud to a convention of investment bankers.

When the idea is getting closer to realisation, his business partner, whose seen a woman professor of atmospheric studies on television saying it is getting cooler, starts to wonder if people will still be willing to pay for alternative energy sources. Beard reassures his partner by saying :

'Here’s the good news. The UN estimates that already a third of a million people a year are dying from climate change. Bangladesh is going down because the oceans are warming and expanding and rising. There’s drought in the Amazonian rainforest. Methane is pouring out of the Siberian permafrost. There’s a meltdown under the Greenland ice sheet that no one really wants to talk about. Amateur yachtsmen have been sailing the North-West Passage. Two years ago we lost forty per cent of the Arctic summer ice. Now the eastern Antarctic is going… It’s a catastrophe. Relax!’


Remember, the author accepts that anthropogenic climate change is taking place yet here he is lampooning the tendency of ‘warmists’, to revel in bad news. The ‘deniers’ are no better; they are never happier than when airports are closed by snow storms and motorists are trapped by blizzards.

Despite the author’s beliefs he has the perspicacity to see participants from both sides, warts and all, in a clear objective way; if only those who write technical books on climate change were as perceptive about the science.

Author: Ian McEwan

Publisher: Jonathon Cape, 2010

ISBN: 9780224090490

Is Google biased in favour of climate change?

Google ranks pages from 0 to 10 using a page rank (named after Lawrence Page). The higher the rank the more likely is Google to send an enquiry to that page. Sites with the maximum rank of 10 include CNN.com and BBC.co.uk.

About a year ago my colleague and I set up links to the most popular climate change blogs, those with a Google page rank of 5 or above. We’ve just revisited the blogs and found that whilst changes to ‘non-sceptic’ blogs are fairly neutral (as many upgraded as downgraded) for ‘sceptic’ blogs there have been more downgrades than upgrades. The following table summarises the situation.

Site type Change Number Non-sceptic +1 9 Non-sceptic 0 23 Non-sceptic -1 7 Non-sceptic -2 1 Sceptic +1 2 Sceptic 0 25 Sceptic -1 10 Sceptic -2 3

The non-sceptic blogs are almost in balance with 9 up and 8 down; one has dropped by 2 places but that blog has only posted once since early December 2009. On the other hand only 2 sceptic blogs have increased but 13 of them have fallen, three of them by two points. Unlike the non-sceptic blog which fell by 2 points all three of the sceptic blogs which fell by 2 points had posted something new in the last few days, though one of them had moved its web site to a new address.

It cannot be a function of number of visitors. Alexa, the web information company, gives “Watts up with that” as the most popular climate blog and it has a page rank of 7. On the other hand “Realclimate” according to Alexa has had a quarter of the visitors to ‘Watts’ over the last 3 months but has a page rank of 8. “ClimateAudit”, which also has more visitors than “RealClimate” also has a page rank of 7.

There are also several non-sceptic sites which get less than one percent of the visitors of ‘Watts’ but have the same rank of 7.

The conclusion, unlikely as it may seem, is that Google does have a bias – against climate sceptics.

Postscript
As several people have pointed out on blogs where we have linked to this, and we ourselves were aware, Google's ranking system is complex, secret and changing. None-the-less it does seem strange that at a time when opinion polls suggests that sceptics are in the ascendant there should be a diminution in the their Google rankings.

A. W. Montford: The Hockey Stick Illusion

If you’ve found this review you probably know the story but basically it is this. Temperatures before the middle of the 19^th century can only be estimated indirectly from proxies: physically measurable characteristics of plants or animals which lived at earlier times and which respond to temperature changes. In 1999 a young climate researcher, Michael Mann, and colleagues published a paper in Nature which suggested that temperatures at the end of the 20^th century were higher than at any time in the previous 600 years. The graph of this, shaped like an ice-hockey stick, became iconic and appeared several times in the IPCC 2001 technical assessment report and elsewhere. In 2002 a retired mining engineer, Steve McIntyre, became suspicious of the fact that the paper both contradicted conventional wisdom and gave an ideal message for climate change activists that he started to investigate. His findings led to Congress setting up to two high level technical enquiries and a congressional committee held hearings.

Those of you who have seen my review of ‘Dire Predictions’ by Mann and Kump might imagine that I would automatically give a favourable review to this book. After all it is the very antithesis of the view of climate by IPCC insiders like Mann and Kump. But that is not how we work at climatedata.info. We try, as far as possible, to avoid polemics for polemics sake and let the data speak for themselves.

The author of this book, Andrew Montford, is a blogger who uses the pseudonym ‘Bishop Hill’. He started off as a political blogger and has a Bill of Rights for the UK on his site.  The Bill of Rights shows that he is of a libertarian disposition and is therefore not predisposed to accept the restrictions which would be necessary to bring about a major reduction in carbon emissions. He admits in the book that his site only took off when he started blogging on climate the ‘Hockey Stick’.

The book reads well, is well referenced, and appears to be a crushing indictment of the IPCC and the paleoclimatologists who developed the ‘Hockey Stick’. To the author, Steve McIntyre is definitely one of the ‘good guys’ and beyond reproach. Whilst it tries to present arguments from both sides there is no doubt that the book is very partisan.

In referring to the meeting to discuss the ‘Hockey Stick’ by the National Academy of Sciences in the USA he discusses the response of Michel Mann to a question concerning verification of the calculations. In a published paper Mann had reported that he had calculated a particular statistic (r squared). In the book he is quoted as telling the meeting “We didn’t calculate it. That would be silly and incorrect reasoning.” I have Googled those phrases and the only source I can find is Steve McIntyre’s blog at climateaudit.org which is the source referenced by the author. There appears to be no transcript of the NAS meeting, at least I could not find one online. I have also studied the transcript, and listened to much of the recording, of the subsequent congressional hearing and can find no evidence to support what is claimed to have been said at the NAS meeting. My attempts to get to the bottom of this do not prove or disprove what has been claimed but to make such a serious charge without independent  verification is a clear example of bias.

Throughout the book frequent reference is made to scientists withholding data and there is always the assumption that if data is withheld there are nefarious reasons for it. One of McIntyre’s complaints was that Bristlecone Pine trees were central to calculation of the ‘hockey stick’ but that the data from the trees stopped in 1980, just as the main warming started. He therefore set about visiting the site to resample the trees. This was done and the cores were re-analysed. I have tried to access the data using the links on his site including http://climateaudit.org/data/colorado/SMCD.dat but the links are dead. In a footnote in the book the author says [McIntyre] “has yet to publish the findings in a journal.” I am not assuming there is anything sinister in this but the fact that the author so glibly accepts the lack of openness from McIntyre but assumes ill-intent from others is a further demonstration of his bias.

Enough of the polemics: where does this leave the science?

Climate scientists are under pressure from politicians to present a clear picture. There is no dispute about the fact that many climate scientists felt that if temperatures had been warmer in the historic past than the present this would dilute the message they could deliver to the politicians. When a climate scientist appeared to be able to prove that current temperatures were indeed higher than in the past millennium they jumped at it as way of getting their message across. The ‘Hockey Stick’ became the star of the 2001 IPCC report.  However my feeling is that on balance the climate science community regrets the prominence given to the hockey stick. There are two reasons for this.

Firstly the aim of the IPCC is to convince the public of the necessity to take action on climate change. The use of temperature proxies has been so well discussed that many well informed citizens are aware of the need to ‘hide the decline’ or believe that everything is based on a few trees in Siberia. The ‘decline’ refers to the fact that in recent decades trees in  the northern hemisphere are not responding to temperature increases in the way they were assumed to; this brings into question the accuracy of long-term temperature estimate based on tree rings. Many people also believe that scientists have ‘cherry-picked’ the trees, the Yamal series from Siberia, that give the answer they want.  This was one of McIntyre’s first criticisms of Mann, that his method selected proxies that gave a ‘hockey stick’. Many scientists now would agree that temperatures in the medieval period were similar today but the science is not accurate enough to be able to say whether they were slightly warmer or cooler.

In an attempt to support the ‘hockey stick’ some climate scientists, including Mann and Kump in their book, say they accept that in parts of the world the medieval period was warm but the warming was less general than today. This argument is a bit disingenuous. In those parts of the world where written records of the medieval period exist there is evidence that medieval temperatures were high but of course not all parts of the world have written records of that period. So the argument comes down this; one side says “warming only occurred in parts of the world with written records”, and implies it did not elsewhere and the other side says “warming occurred in all parts of the world with written records” and implies that it did elsewhere.

Secondly, the question of past temperatures does not of itself determine whether or not anthropogenic warming is taking place. The temperature could be rising as a result of human action now even if temperature in the past were higher than today. Where it is critical is in discussing the impacts. If temperatures had been 2 °C higher in the past it is difficult to argue that a rise of that order of magnitude would be catastrophic.

From reading his blog I have always felt that Steve McIntyre viewed his role as scientific and he has made many attempts to reach out to the scientific community. Andrew Montford definitely has a political agenda and would probably be sceptical about climate change whatever the science said. I am not sure that McIntyre is well served by this book.

Author: A. W. Montford

Publisher: Stacy International, 2010

ISBN: 978 1 906768 35 5

Michael Mann and Lee Kump: Dire Predictions – Understanding Global Warming

The Reader’s Digest magazine used to publish what they referred to as “unexpurgated abridgements.” By this they meant that they had left in the exiting bits and cut out the boring bits. This book could be considered an “unexpurgated abridgement” of the IPCC 2004 Technical Assessment Report. A lot of the detailed science has been left out but the elevated temperatures and other symptoms associated with an attack of ‘dire era’ are given lurid prominence.

The book does give a clear and approachable synopsis of how our climate operates and how human activity can lead to changes. As an introduction to the science, the book is quite good. It is clearly written and has good supporting material. It also tackles some of the issues raised by sceptics.

In a recent double interview in Discover magazine with Judith Curry and Michael Mann, Judith Curry drew a nice distinction between ‘political sceptics’, who do not want climate change to be true, and ‘scientific sceptics’, whose opinions are based on the evidence. I would suggest that there is a third type of sceptic: the ‘bar-room’ sceptic, who’s not reticent about sharing his knowledge over the internet. You know the type “Why does the IPCC ignore the book ‘The incredible lightness of being’ by the Russian Milan Kovich which proves CATEGORICALLY that the recent so-called warming has all been due to fluctuations in the earth’s orbit?”  Unfortunately the authors tend to engage with this level of sceptic rather than the scientific sceptics. The issues where there is real scientific debate, the ‘hockey-stick’ and the urban heat island effect are either ignored or glossed over. Instead they rebut claims that the increase in CO2 is due to natural fluctuations, which scientific sceptics generally accept, or raise the hoary chestnut of “In the 70s the scientists said we were in for global cooling so why should we believe them now?”

The way they tackle the cooling/warming issue says a lot about the authors’ scientific credibility. They present a pair of graphs (page 45 in my edition) which show that the northern hemisphere temperature fell from 1940 to 1970, which explained the then current belief in cooling, and then again increased. Like the rest of their graphs there is no reference to the source but as it starts in 1850, and only the CRU record started in that year, it is reasonable to assume that that was the source.  Yet their graph is very different to the CRU one: they show temperatures rising from 1970 to the present by 1.8 °C but the CRU data shows a rise of less than half of that. Elsewhere (pages 20 and 88 in my edition) they show graphs of ‘past observed surface temperature changes’ with an almost constant rate of temperature rise and no sign of the 1940 to 1970 fall. This is very different to the above graph. Since the observed global temperature record shows similar variation to the northern hemisphere record that does not explain the anomaly. Once again without references it is difficult to be definitive but it is almost certainly the ‘modelled’ temperature increase which they have presented as ‘observed’. This gives the false impression that the temperature increases projected by the models follow on naturally from steadily rising observed temperatures.

The book is in fact heavy on dire predictions, based on model projections, but very light on evidence that the models were able to represent past changes accurately. For example, they talk of precipitation changes as being probably of ‘more importance than temperature changes’ but present not a shred of evidence of how well models simulated precipitation.  At least the IPCC report does have a shred of evidence: a graph which occupies 1/8 of a page!

What is most frustrating is the fact that this biased, one-sided, presentation of the facts is counter-productive. I fully accept that people are in part responsible for the recent temperature increase. I fully accept that there are many reasons, one of which is CO2 emissions, for reducing fossil fuel consumption. I fully accept that climate projections should play a major role in how we plan for the future. Yet, largely because the IPCC and scientists chose to ignore Abraham Lincoln’s dictum and think that in this ‘information age’ they can ‘fool all of the people all of the time’, the number of climate change sceptics is currently growing.

To give a final example: in his book “Cool It” Bjorn Lomborg mentions the 35,000 people killed in a heat wave in Europe. He also mentions that many more people die of cold in winter and follows it with a nuanced discussion of age profiles and the difficult moral question of how you balance the deaths of old people and of children. In this book only the heat deaths are mentioned. If you are an intelligent, thoughtful, person which approach is most likely to help form your opinion?

I also noticed a typo on the back cover where the book is described as being a scientifically ‘based’ overview. And where, you might ask, is the typo? It’s the missing “i” of course? 

Authors: Michael Mann and Lee Kump
Publisher: Dorling Kindersley, 2008
ISBN: 978-0-7566-3995-2

Archer and Rahmstorf: The Climate Crisis - An introductory guide to climate change

“I feel that it is important to not let bad, politically motivated science stand unchallenged.“ This is a quote we could all agree with and is part of the motivation behind our site. Only too often both ‘deniers’ and ‘warmists’ select a sub-set of the available science and then push it beyond reasonable limits to further their cause. Our mission is to sort out the justifiable from the bogus.

The authors of this book are, to use the current term, ‘warmists’. Their book is based largely on the IPCC 2007 assessment report which both of them contributed to. To their credit the authors have managed to avoid some of the recent brick-bats thrown at the IPCC. They do not repeat the scientifically dubious claims regarding Himalayan glaciers, African agriculture or the Amazonian rain forest. What is more they found no space in their book for any reference to Dr Pachauri, Chairman of the IPCC, whose commercialisation of the IPCC in the interest of organisations he is associated with has attracted much opprobrium. That said, there is a lot of politically motivated science in their book.

One of the most egregious examples of trying to gull the gullible is in their figure 3.1, reproduced below:

This purports to show that the linear trend of temperature increase is accelerating but is completely spurious for two reasons. Firstly, given that temperatures have been both rising and falling, there will always be short periods when the rate of rise is higher than the long-term average. Secondly, the 25-year rate of rise around the period 1910 to 1945 is almost the same as the 25-year period they show at the end of the record. The authors repeat their claim in the chapter summary: “Measurements unequivocally show that we are in are in the midst of an accelerating global warming”. They are wrong: there is no evidence that the rate of temperature increase is accelerating. [Postscript. The authors attribute this figure to the IPCC TAR4 Summary for Policy Makers figure 3, which does have a plot of temperatures, and I assumed they had added the rate of temperature rise. In fact the figure comes directly from the IPCC Technical Summary figure 6. So, I apologise to the authors for trying to hoodwink the public; they themselves had been hoodwinked by the IPCC.]

The authors do something similar with sea level rise. They state (correctly) that the rate of rise over the 20th century estimated from tide gauges averaged 1.7 mm/year. They also state that, in 2003 when the IPCC report was prepared, satellites had been showing a rate of increase since 1993 of 3.4 mm/year (also correct). They conclude that this indicates ‘the sea level rise has accelerated in recent decades.’ What they do not tell us, though Rahmstorf as a Professor of the Physics of the Oceans must have known, is that the rate of level rise has fluctuated and a rate of 3.4 mm/year was not unknown in the past. What they also should also have known, since their book was published in 2010, is that for the last few years the rate of rise estimated by the satellites has hovered around the long term rate of 1.7 mm/year. Again the facts show their science is politically motivated.

The book is well produced with colour photos and graphs. The use of colour seems sometimes to be at the expense of the science. The statement “in many parts of the world, the fraction of the total annual rainfall that comes down on just a few very wet ways has increased” refers to figure 3.6. Rather than a graph supporting this assertion we get a photo of bus driving through about 20 cm of water. Another example of a disconnect between the text and the cited figure relates to tropical cyclones. They quote the IPCC report as saying there is “no trend in the total number [of tropical cyclones] that occur each year” then show a graph of Tropical Cyclone counts. This graph incidentally has 4 lines, only 3 of which are referenced in the key. In relation to hurricanes the other claim they make, that ‘trends since the 1970s [are] towards more intense and longer-lasting cyclones’, may be true but ignores the fact the estimates of cyclone energy since 1851 show periods of rising energy, 1860 to 1890 and 1920 to 1950, similar to that from 1970 to 2005. The Energy Index for 2009 was actually below the average in the 1970s. The authors could not, of course have known that particular fact at the time of writing, but quoting short-term trends as evidence of long-term climate change carries the risk that a reversal of the short-term trend appears to invalidate the argument. I use the word “appears” advisably; in reality short-term trends in a system with as many “random jitters” (their phrase) as our climate say next to nothing either away about long-term changes.

One might expect the author of the quote at the head of my review to applaud my efforts to debunk politically motivated science. It won’t happen. The quote is from an email sent by Stefan Rahmstorf himself.

Authors: David Archer and Stefan Rahmstorf
Cambridge University Press, 2010
ISBN: 978-0-521-73255-0