IPCC Technical Assessment Report 5 – Thesis 3

Thesis: The presentation of sea ice in TAR4 used only a sub-set of the data. It should use a wider range of data with reference both to data which were available at the time of TAR4, and data which have become available since.

The technical summary presents the following set of graphs:

 

The way the graphs are presented is reminiscent of graphs of return on investment of rivals presented by some of the less honest financial intermediaries.  Those for the Arctic are presented as anomalies with a scale set so that the full range fits in the rectangle and it seems as if ice extent has fallen close to zero. For the Antarctic, where the area of ice has been tending to increase, they have used the same scale which conveniently minimises the increasing tendency of Antarctic ice.

The following graph presents the same data, updated to May 2010, but as extent not anomalies.

This very clearly shows that on average there are similar areas of sea ice in the Arctic and Antarctic, that the variation is much larger in the Antarctic than the Arctic and the loss of sea ice in the Arctic is only partially balanced by the gain in the Antarctic.  A linear regression through the average values suggests that the Arctic has lost 50,000 km² per year whereas the Antarctic has gained 14,000 km2 per year. The average total area of sea ice 23.9 million km² so this loss represents a rate of 0.15% a year.

The Synthesis Report also mentions the break-up of the Larsen B ice shelf.  This was an area of ice partly floating and partly resting on land and joined to the main Antarctic ice shelf. It was located on the most northerly (i.e. warmest) point of the Antarctic. The area of the ice shelf was 3250 km² and its weight was 72 billion tons. The loss of the ice shelf has become iconic and it has been compared to the area of Rhode Island or to the trillions of 20 lb bags which could be filled (though not in the IPCC report).  In relation to the area of the Antarctic ice sheet it represents only 0.02% of the area or 0.003% of the volume.

We do recognise that the minimum area of sea ice is a useful metric. The albedo (reflectivity) of ice is high and that of sea water is low. In summer, when ice is at a minimum and sunlight at a maximum, the albedo effect is important and the fears that the low Arctic minimum of 2007 could lead to a progressive reduction in sea ice area were valid.

At the time of the TAR4 there was little information available on ice depth and volume. From October 1998 daily values of ice thickness are available from the US Navy polar ice prediction system(PIPS). The forecast values of ice thickness use weather forecasts, and buoys and ice concentration data from the Special Sensor Microwave Image (SSM/I) are used to initialize the system's forecast. The results are available as GIF images. A typical one is given below.

To derive areas and volumes the graphic images were downloaded analysed.  The projection used is not an equal area project so the areas derived were approximate. They were based pro-rata on a scanned image of Greenland. During the analysis it was found that the colours representing thickness range 0.5 to 0.75 were never present. It should also be noted that occasionally there were anomalous values, for example for a few days the Caspian and Aral seas were included.

The following graph shows the area and volume of sea ice from October 1998 to May 2010. These figures only apply for ice greater than 0.75 m thick and consequently the areas are less than those of ice extent in the above graph.

 In general the volume and area show similar variation but after the low summer minimum of 2007 the ice area recovered well in 2008 but the volume. This is reflected in the chart on ice thickness.

This shows that minimum ice thickness was less in 2008 than in 2007, giving some support to those who said the ice that year was “rotten”. It is interesting to note that the ice thickness is bi-modal; one maximum occurs in May when the ice area has just passed its maximum and the second in September near to the point when it is at its minimum. This can be seen more clearly in the following graph where compare average thickness with current ice thickness.

The shape of the graph suggests that ice thickness is belatedly reaching its spring maximum. How it will develop in the coming months is something we will follow with interest. What these graphs do show is that Arctic sea ice is recovering in terms of volume, are and thickness.

In these “theses” we generally do not concern ourselves with short term effects so to counter that remember that during the last inter-glacial sea levels were 6 m higher than at present.  Although melting sea ice does not affect sea levels we can none-the-less expect more melt independent of any anthropogenic effect. 

IPCC TAR5: The presentation of graphs data in TAR5 was biased to give an exaggerated impression of ice loss. In TAR5 the presentation should be more balanced. It should use a wider range of metrics to assess changes in sea ice.

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.

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

Sceptics Now Welcome

Over the last few months there has been a remarkable change of tone among the climate science community. Until recently sceptics were treated as barely worth the consideration of ‘real’ climate scientists. The CRU emails showed clearly how attempts were made to prevent the publication of any paper questioning climate orthodoxy or, should such a paper have been published, to prevent it appearing in any IPCC publication. That has now changed; or at least the rhetoric has changed; only time will tell if the underlying philosophy has changed.

One sign of this was a recent article in a national newspaper by the UK government’s Chief Scientist, John Beddington. In the article he says “The impact of global warming has been exaggerated by some scientists and there is an urgent need for more honest disclosure of the uncertainty of predictions about the rate of climate change.” Not to be outdone his predecessor, David King, has weighed in with an article which makes a similar point.

This is in marked contrast to a statement by the same David King in 2004, who was still at the time in post, that climate change was a bigger threat than terrorism. Not much sign of scientific openness there.

The discussion of the CRU emails, when they got through to the main stream media, was probably the first time many of the public were aware of any dissention regarding the inevitability and magnitude of climate change. In this atmosphere of heightened awareness we have had ‘Glaciergate’, ‘Amazongate’ and now “Africagate”.
The first of these, Glaciergate, related to claims in an official IPCC report that glaciers in the Himalayas could disappear by the year 2035. The claim was based on speculation by an Indian scientist in an interview with the New Scientist, a British popular science magazine. This claim was included in a report by the WWF which was quoted by the IPCC as a reference. Although a number of comments were made during the draft stage of the IPCC report it was not removed. Initially the IPCC tried to defend the claim. Dr Pachauri the chairman of the IPCC said criticism was based on ‘voodoo science’. However the IPCC has now accepted that the claim was without justification.

Amazongate refers to a claim in another IPCC report that “up to 40% of the Amazonian forests could react drastically to even a slight reduction in precipitation". As a source the IPCC again referred to a WWF/IUCN publication on forest fires. This time the WWF publication did give a reference – to a publication in the highly respected science journal “Nature.” That article was titled “Large-scale Impoverishment of Amazonian Forests by Logging and Fire”. In it there is a reference to 40% but it is to selective logging which leaves the remaining forest vulnerable to fire. There is a separate reference to sensitivity to drought during El Nino events. So again, the IPCC claim is not substantiated.

The third of these claims relates to African agriculture. IPCC has claimed that in some African countries, yields from rain-fed agriculture could be reduced by up to 50 percent by 2020. Whereas the other two claims in were in specific sections of the main body of the report, this claim appears in the synthesis report which highlights the most important issues. Dr Pachauri was himself a contributor to this report and has quoted the claim on many occasions. As with the other claims a report from an advocacy group is given as source and tracing the references back reveals a different picture to that presented in the IPCC report. The report was based on submissions to the IPCC from three countries: Algeria, Tunisia and Morocco. Only one of these uses the figure of 50% relating it specifically to grain yields in drought years with a lesser reduction in other years. So from a statement relating to one country and one crop under specific conditions the IPCC has produced a statement which appears to have implications for all rain-fed crops for the whole of Africa.
These three specious claims were revealed by sceptics not by the IPCCS internal review system. No wonder sceptics were not welcome in the past.

The defence of the IPCC to these errors has been to say that in a series of reports totalling 1,000s of pages a few errors are not unsurprising, true, and that they do not call into question the underlying science of climate change, also true. That misses the main point. At the highest level the IPCC was using unsubstantiated claims regarding the impact of climate change to further its case and scientists who were aware of the fallacies in these claims felt cowed and failed to speak out.
The IPCC is part of the United Nations system which has the delicate task of according equal status to all its members whilst also acting as a conduit for development aid to some of them. In Africa, Asia and South America (regions where these problems occurred) there are UN member countries in receipt of development assistance. Some of these do not have adequate budgets for their national meteorological services let alone the super computers, free access to the scientific literature and funds for conference attendance that ‘western’ climate scientists expect. One telling comment from one of the IPCC draft report reviewers was that he could not assess a comment as he was not able to access a copy of the Nature article which someone had mentioned in that comment.

So what for the future?

There have been suggestions that the IPCC has outlived its usefulness and should be replaced. This won’t happen. As Copenhagen showed, future action will depend on interaction between high carbon and low carbon emitting countries and this is only possible within the context of the UN. There have also been calls for the replacement of Dr Pachauri as Chairman of the IPCC. If this happens it will done following UN established procedures. Dr Pachauri was appointed to replace the previous chairman who was seen by the US to be too ‘warmist’; it was political move and political considerations will predominate in any replacement. The only debate will be whether he should be replaced by someone from another Asian country or whether it is now the turn of South America or Africa.

It is significant that the most articulate scepticism has come from a class which could be described as ‘technical non-academic professionals’. This describes people like Steve McIntyre (minerals exploitation), Anthony Watts (meteorologist) and David Holland (engineer). The leading sceptical blogs often have article-length postings from people, probably from a similar background, who have examined climate records in detail and raised serious questions about the way they have been processed. The scrutiny these people provide is more intensive and searching than that provided by peer review (aptly renamed ‘pal review’ by one blogger).

This suggests a way forward. There is a large group of technically qualified people who, whilst not climate scientists in the strict sense of the term, have spent their lives working with climate data: in areas such as water resources, urban drainage, irrigation, dam spillway design, etc. It is such people who have identified the weakness of the academic approach; they should be given a chance to see if they can do better.