One of the stunning coincidences is that Andrew Bolt and I are born within a few hours of each other.  While similar in many ways (e.g. born on 26th Sep 1959, both have European born fathers), we differ in our understanding of climate change.

Screen shot 2009-09-24 at 9.32.45 AM

I thought I might help him with a little science-based information on his favourite subject (I am a scientist afterall) by putting together the following birthday card:


So, happy 50th birthday Andrew!

I am still waiting for the copy of the synthesis report of the 4th assessment of the IPCC that I have ordered for Andrew’s birthday to arrive. I hope he reads and learns from it, but after all, this is the same Andrew Bolt who said “I am not a scientist, and cannot have an informed opinion on your research”. Thanks to Global Warming Art for the graphs used above.

Edit: Sources for the above graphs from Global Warming Art (1-5, 7) except for (6), which is sourced from Climate Change in Australia:

1.  The instrumental record of global average temperatures as compiled by the NASA‘s Goddard Institute for Space Studies. The data set used follows the methodology outlined by Hansen et al. (2006). Following the common practice of the Intergovernmental Panel on Climate Change, the zero on this figure is the mean temperature from 1961-1990.

The uncertainty in the analysis of global temperature is discussed in Foland et al. (2001) and Brohan et al. (2006). They estimate that global averages since ~1950 can be expected to be within ~0.05 °C of reported values with 95% confidence. In the recent period, these uncertainties are driven primarily by considering the potential impact of regions where no temperature record is available. For averages prior to ~1890, the uncertainty reaches ~0.15 °C driven primarily by limited sampling and the effects of changes in sea surface measurement techniques. Uncertainties between 1980 and 1890 are intermediate between these values.

Incorporating such uncertainties, Foland et al. (2001) estimated the global temperature change from 1901 to 2000 as 0.57 ± 0.17 °C, which contributed to the 0.6 ± 0.2 °C estimate reported by the Intergovernmental Panel on Climate Change (IPCC 2001a, [1]). Both estimates are 95% confidence intervals.

2. This figure compares the global average surface temperature record, as compiled by Jones and Moberg (2003; data set TaveGL2v with 2005 updates), to the microwave sounder (MSU) satellite data of lower atmospherictltglhmam version 5.2 with 2005 updates) and Schabel et al. (RSS 2002; data set tlt_land_and_ocean with 2005 updates). These two satellite records reflect two different ways of interpreting the same set of microwave sounder measurements and are not independent records. Each record is plotted as the monthly average and straight lines are fit through each data set from January 1982 to December 2004. The slope of these lines are 0.187°C/decade, 0.163°C/decade, and 0.239°C/decade for the surface, UAH, and RSS respectively.

It is important to know that the 5.2 version of Christy et al.’s satellite temperature record contains a significant correction over previous versions. In summer 2005, Mears and Wentz (2005) discovered that the UAH processing algorithms were incorrectly adjusting for diurnal variations, especially at low latitude. Correcting for this problem raised the trend line 0.035°C/decade, and in so doing brought it into much better agreement with the ground based records and with independent satellite based analysis (e.g. Fu et al. 2004). The discovery of this error also explains why their satellite based temperature trends had disagreed most prominently in the tropics.

3. This figure shows the change in annually averaged sea level at 23 geologically stable tide gauge sites with long-term records as selected by Douglas (1997). The thick dark line is a three-year moving average of the instrumental records. This data indicates a sea level rise of ~18.5 cm from 1900-2000. Because of the limited geographic coverage of these records, it is not obvious whether the apparent decadal fluctuations represent true variations in global sea level or merely variations across regions that are not resolved.

For comparison, the recent annually averaged satellite altimetry data [1] from TOPEX/Poseidon are shown in red. These data indicate a somewhat higher rate of increase than tide gauge data, however the source of this discrepancy is not obvious. It may represent systematic error in the satellite record and/or incomplete geographic sampling in the tide gauge record. The month to month scatter on the satellite measurements is roughly the thickness of the plotted red curve.

4. This figure shows the change in average thickness of mountain glaciers around the world. This information, known as the glaciological mass balance, is found by measuring the annual snow accumulation and subtracting surface ablation driven by melting, sublimation, or wind erosion. These measurements do not account for thinning associated with iceberg calving, flow related thinning, or subglacial erosion. All values are corrected for variations in snow and firn density and expressed in meters of water equivalent (Dyurgerov 2002).

Measurements are shown as both the annual average thickness change and the accumulated change during the fifty years of measurements presented. Years with a net increase in glacier thickness are plotted upwards and in red; years with a net decrease in glacier thickness (i.e. positive thinning) are plotted downward and in blue. Only three years in the last 50 have experienced thickening in the average.

Systematic measurements of glacier thinning began in the 1940s, but fewer than 15 sites had been measured each year until the late 1950s. Since then more than 100 sites have contributed to the average in some years (Dyurgerov 2002, Dyurgerov and Meier 2005). The percentage of measurement sites at which net thinning has been observed averages two-thirds over this interval, and reached a maximum of 96% in 2003 (Dyurgerov 2005). Error bars indicate the standard error in the mean.

5. This figure, which reproduces one of the key conclusions of Knutson & Tuleya (2004), shows a prediction for how hurricanes and other tropical cyclones may intensify as a result of global warming.

Specifically, Knutson & Tuleya performed an experiment using climate models to estimate the strength achieved by cyclones allowed to intensify over either a modern summer ocean or over an ocean warmed by carbon dioxide concentrations 220% higher than present day. A number of different climate models were considered as well as conditions over all the major cyclone forming ocean basins. Depending on site and model, the ocean warming involved ranged from 0.8 to 2.4 °C.

Results, which were found to be robust across different models, showed that storms intensified by a about one half category (on the Saffir-Simpson Hurricane Scale) as a result of the warmer oceans. This is accomplished with a ~6% increase in wind speed or equivalently a ~20% increase in energy (for a storm of fixed size). Most significantly these result suggest that global warming may lead to a gradually increase in the probability of highly destructive category 5 hurricanes.

This work does not provide any information about future frequency of tropical storms. Also, since it considers only the development of storms under nearly ideal conditions for promoting their formation, this work is primarily a prediction for how the maximum achievable storm intensity will change. Hence, this does not directly bare on the growth or development of storms under otherwise weak or marginal conditions for storm development (such as high upper level wind shear). However, it is plausible that warmer oceans will somewhat extend the regions and seasons under which hurricane may develop.

6. Projections are given relative to the period 1980-1999 (referred to as the 1990 baseline for convenience). The projections give an estimate of the average climate around 2030, 2050 and 2070, taking into account consistency among climate models. Individual years will show variation from this average. The 50th percentile (the mid-point of the spread of model results) provides a best estimate result. The 10th and 90th percentiles (lowest 10% and highest 10% of the spread of model results) provide a range of uncertainty. Emissions scenarios are from the IPCC Special Report on Emission Scenarios. Low emissions is the B1 scenario, medium is A1B and high is A1FI.

7. This image is a comparison of 10 different published reconstructions of mean temperature changes during the last 1000 years. More recent reconstructions are plotted towards the front and in redder colors, older reconstructions appear towards the back and in bluer colors. An instrumental history of temperature is also shown in black. The medieval warm period and little ice age are labeled at roughly the times when they are historically believed to occur, though it is still disputed whether these were truly global or only regional events. The single, unsmoothed annual value for 2004 is also shown for comparison. (Image:Instrumental Temperature Record.png shows how 2004 relates to other recent years).

It is unknown which, if any, of these reconstructions is an accurate representation of climate history; however, these curves are a fair representation of the range of results appearing in the published scientific literature. Hence, it is likely that such reconstructions, accurate or not, will play a significant role in the ongoing discussions of global climate change and global warming. For each reconstruction, the raw data has been decadally smoothed with a σ = 5 yr Gaussian weighted moving average. Also, each reconstruction was adjusted so that its mean matched the mean of the instrumental record during the period of overlap. The variance (i.e. the scale of fluctuations) was not adjusted (except in one case noted below).

Edit #2:As per ilajd’s comment below, here is the Hadley CRUT3V adjusted for UHI (scale adjusted to match graph #1)



49 Responses to Happy Birthday to… Andrew Bolt!

  1. John Bruno says:

    amazing, clearly separated at birth…

  2. Roger Jones says:

    Happy Birthday, evil twin! (well almost)

    I didn’t know about the Bolt thing though. Spoooky.

  3. Eli Rabett says:

    Eli believes that the Summary for Policy Makers of the AR4 was written for non-scientists. You might bookmark it.

  4. Allan says:

    More graphs from Wikipedia and unreferenced!
    Maybe they come from Hanno 2009

  5. Alan: The graphs are sourced from Global Warming Art (not Wikipedia), and i’ve updated the post to include sources for the graphs. Any more specific comments?

  6. Eli: agreed. There is a copy of the Summary for Policy Makers of the AR4 in the post to Andrew as I type (although I doubt it’ll do much good). Any other suggestions for non-scientists and non-policy makers?

    Here’s the link to the pdf for bookmark purposes:

  7. Eli: Agreed – there is a copy in the post for Andrew as I write this, and I hope he will take the time to read it through. Do you have any other suggestions for the non-scientists?

    (Here is a link to the Summary for Policy Makers of the AR4 for reference:

  8. Ian says:

    Your ’1,000 year record’ is based on a fraud….

    How can we trust the other data you present? I understand that the latest UN Climate report is also making it up as they go along.

    Are you teaching your students that this is the way science is done? Perhaps Mr Bolt is not the evil twin after all.

  9. ilajd says:

    A different and perhaps more honest version of graph 1 can be found at the following website (below). Ove, how does the one you show deal with UHI?

    for discussion see “Why We Need a New Global Data Set”

  10. ilajd says:

    Graph 7. I wonder if this takes Steve Mc Intyre’s recent auditing into account (below)? The Wegman report also provides some interesting information on this graph.

    By the way for a science blog this site is seriously lacking in basics-Where are the error bars Ove? Richard Feynmann (RIP) would happily describe this behaviour as Cargo Cult science. I hope you are proud of yourself!


    For an alternative Graph 7. See:

  11. Iljad: Thanks for the link (which is also lacking error bars!). I’ve added the adjusted for UHI graph in the post above and adjusted the axis to match that of graph 1.

    Ian, Iljad: Which of the ten reconstructions in graph 7 do you disagree with? (anyone not familiar with the ‘hockey stick controversy’, see Wikipedia’s article discussing both the National Research Council Report and the and Wegman Report)

  12. ilajd says:

    Ian (and Ove), Anyone familiar with the Hockey Stick controversy would be familiar with the close links between authors of palaeoclimate studies featured in the graph produced in the IPCC report. Many of these studies rely in the same flawed proxies, so it is no surprise that they are broadly similar. Again the level of scientific dishonesty in your omission of this information is surprising. Climate Audit provides much more detailed information about the problems surrounding selective use of proxies (read cherry picked data), and of the intrinsic difficulties and large errors of deriving temperature from such things are tree rings and lake sediments whose variation is a reflection of a variety of factors.

    Your sea level graph (3) is equally dishonest.

    Nepotism in science is just as destructive as it is in politics. Again Feynmann would not be proud.

  13. Sebastian says:

    Sorry ilajd, but you are going to have to do better than that for criticism. You can’t argue that all palaeographs are dishonest as they rely on ‘flawed proxies’, then justify their existence through apparent scientific nepotism. If your aim is to enlighten the good people of this blog rather than peddle an agenda, be more specific with your criticism of ‘scientific dishonesty’.

  14. ilajd says:

    Hey Sebastian, and Ove, and Ian,
    Regarding the Hockey Stick – the link to Climate Audit above shows that when all of the tree ring data from “Yamal” is plotted, the famous hockey stick disappears. Not only does it disappear, but goes negative. The conclusion is inescapable. The tree ring data was hand-picked to get the desired result. This series features in other graphs in the figure reproduced by Ove. Seems you all support this type of practice and have the gall to call it science. Honesty from climate alarmists-give me a break.”

  15. Sebastian says:

    Iljad, I’m struggling to see where the Yamal data fits in the source data for graph 7. Rather than throwing about broad claims of dishonesty, try and be more specific here (otherwise you risk falling into the same trap of ‘dishonesty’). As Ove asked, “Which of the ten reconstructions in graph 7 do you disagree with?” Note that these are multiproxy graphs, not relying on a single proxy or source.

  16. MAGB says:
    Here are 230 glaciers that aren’t melting.

    and the predictions of increasing tropical storms are wrong:

    Better re-do your research because it is fundamentally flawed.

  17. Ove Hoegh-Guldberg says:

    MAGB: The observation of Himalayan glaciers represents anomalous growth within a region, rather than a global trend or evidence that refutes global warming. Satellite measurements have observed “an overall deglaciation of 21%” from 1962 to 2007 in the Himalayan region (see here for more details). At a global level, glaciers worldwide are shrinking in both area and thickness (For more information, check out the World Glacier Monitoring Service)

    The link to the article in “CO2 Science” interprets findings from cyclones from NW Australia since 1968, not predictions of increasing tropical storms. I’m not sure how CO2 Science think that this fits with their conclusion that: “ever more researchers are arriving at the same general conclusion, i.e., that there has been no long-term increase in TC intensities around the world as the planet has warmed over the Little Ice Age-to-Current Warm Period transition”, as they seem to selectively describe papers that fit their agenda (no long-term increase in intensities), or interpret the results as they see fit (see here for other examples of the loose interpretations of papers by CO2 science )

    Whilst the jury is still out on whether tropical storm frequency is set to increase, global evidence suggests that the intensity of storms is likely to increase. See this article over at Skeptical Science for a more balanced discussion of the link between storms (cyclones, hurricanes, tropical storms) and global warming.

  18. Ian says:

    Hey Ove – I’m sure you will be posting this graph showing how Antarctic sea ice trends show that we are all about to die from global warming.

    The amount of land and sea ice in the Arctic is ‘a drop in the ocean’ compared with the Antarctic yet we hear very little about the southern ice.

  19. Hi Ian, quite to the contrary, I posted an article earlier this week (“Ice melt in Greenland and Antartic intensifying”). The research (published in the journal Nature) has been publicised quite extensively in the media. Using satellite data, the authors compared the rates of change in the elevation of Antartic ice, rather than the extent of the sea ice. Note that this study is from the same same team who published earlier this year that Antartic sea ice is increasing.

    Here’s a quote from the lead author, Dr Hamish Pritchard from the British Antartic Survey:

    We were surprised to see such a strong pattern of thinning glaciers across such large areas of coastline — it’s widespread and in some cases thinning extends hundreds of kilometres inland. We think that warm ocean currents reaching the coast and melting the glacier front is the most likely cause of faster glacier flow. This kind of ice loss is so poorly understood that it remains the most unpredictable part of future sea level rise.

  20. MudCrab says:

    Happy B’day

    may all your dreams come true…. except that one you keep bringing out about the reef’s dying.

  21. Ian says:

    Thanks Ove – I didn’t see your post. It seems strange that ‘warmer water is eating away the edges’ yet the current Antarctic sea ice cover is so much greater than usual. Is this because the warmer water is causing the sea ice to freeze?

    Is the warmer water in Arctic seas also causing the recorded increase in Arctic sea ice over the last couple of years?

  22. Hi Ian, If you take a look at the figure from the Pritchard et al. article in Nature, the measurements plot the range of change in surface elevation, and not too surprisingly show considerable spatial variation across the Antarctic Penninsula. I wouldn’t say that the Antarctic sea ice cover is ‘so much greater than usual’: the Stroeve study found a change in the annual mean ice extent of Antarctica of 0.97% per decade. As the Pritchard study notes:

    The pattern of change now apparent across Antarctica and Greenland is complex, exhibiting the influence of changing precipitation, atmospheric temperature and oceanographic conditions, but the most profound changes clearly result from glacier dynamic effects.

    What mechanism do you suggest by saying that warmer water is causing the sea ice to freeze? In the AP article Pritchard notes that the Antarctic problem is apparently not heat in the air, but warming water and circulation causing the melting. The graphs of Arctic sea ice area and extent show Arctic sea ice as currently well below the 1979-2006 average.

    Mudcrab: Thanks (I think!)

  23. Ian says:

    Hi Ove – Here’s another graph I came across which doesn’t seem to agree with the ‘global warming/we’re all about to perish’ theory….

    There seems to be a long time to go in Greenland before temperatures warm enough to melt the ice if this trend continues.
    What year do you predict that we will see an ice free Greenland?

  24. ilajd says:

    I just noted that Steve McIntyre (see below) has kindly provided an indication of which studies shown in Ove graph 7 are affected by the problems with the Yamal series. The others of course are affected by defective strip bark pines.

    Is this specific enough for you? And what now do you say about the honesty in once again promulgating this graph as being error free? Ove-any thoughts?

    “Studies illustrated in the IPCC AR4 spaghetti graph, Wikipedia spaghetti graph or NAS Panel spaghetti graph (consult them for bibliographic refs) that use the Yamal proxy include: Briffa 2000; Mann and Jones 2003; Jones and Mann 2004; Moberg et al 2005; D’Arrigo et al 2006; Osborn and Briffa 2006; Hegerl et al 2007, plus more recently Briffa et al 2008, Kaufman et al 2009. (Note that spaghetti graph studies not included in the above list all employ strip bark bristlecone pines – some use both.)”

  25. Hi Ian, with every response you seem to shift the goalposts by not actually answering any of the questions you raise… The Greenland ice sheet is either late Pliocene or early Pliestocene, and is over 3km deep. Clearly there will be ‘a long time to go’. When do you suggest the ice will melt? Also, how exactly does a graph detailing the last week of weather disprove the ‘global warming’ theory?

  26. Sebastian says:

    the resulting Yamal chronology with its enormous HS blade was like crack cocaine for paleoclimatologists

    Definitely one of the best quotes of the year. Back to the ‘dishonest’ graph – following your rational, excluding the Yamal dataset knocks out the yellow line (Mann & Jones 2003), orange line (Jones & Mann 2004) & red line (Moberg et al 2005) – leaving 7 of the 10 datasets remaining.

  27. ilajd says:

    Sebastian, you forget about the strip bark bristlecone pines. If you know anything about tree rings you’ll know this knocks them all out.

  28. ilajd says:

    Ove, Just in case you are putting off reading the CLimate Audit post referred to earlier here’s a comment from Steve’s Co-author Ross McKitrick. If this does not get your attention as a scientist i don’t know what else will. As mentioned the Hockey Stick and its relatives in Graph 7 are now dead and buried. So in answer to your earlier question, based on this and other work by McIntyre and McKitrick, I do not think that any of the lines in Graph 7 are close to reality and its perhaps time to move back to earlier graphs used by the IPCC that clearly show a well developed MWP and LIA. With MWP near to present warming. this does not mean that there is no anthropogenic signature it just means its a lot lower than many activists are pushing for. In the end climate sensitivity to CO2 appears to be a lot less than than IPCC models are pushing.

    Comment by Ross McKitrick:
    September 27th, 2009 at 12:54 pm
    Here’s a re-cap of this saga that should make clear the stunning importance of what Steve has found. One point of terminology: a tree ring record from a site is called a chronology, and is made up of tree ring records from individual trees at that site. Multiple tree ring series are combined using standard statistical algorithms that involve detrending and averaging (these methods are not at issue in this thread). A good chronology–good enough for research that is–should have at least 10 trees in it, and typically has much more.
    More at

  29. Hard Of Hats says:

    Ove, why do take a cheap shot at Andrew Bolt?
    I am sure if he was here to respond, he would take your so called evidence of AGW apart easily, as most of the replies so far to your blog have also done. You do not seem to have much compelling evidence for a “Scientist”, you cannot even win debate on you own blog. Please put up some credible evidence if you believe AGW theory is reality.

  30. John Bruno says:

    Hi Ove – Here’s another graph I came across which doesn’t seem to agree with the ‘global warming/we’re all about to perish’ theory….

    There seems to be a long time to go in Greenland before temperatures warm enough to melt the ice if this trend continues.
    What year do you predict that we will see an ice free Greenland?

    Huh? Can you explain that interpretation?

    Thanx jb

  31. Ove,

    I recognized your name over at Deltoid as the author of a particularly good report on the impact of climate change on coral reefs that I made use of during a project with Paul Jokiel a few years back.

    It might be worth updating your #2 graph with the last few years, lest you be accused of neglecting the (only relatively) chilly 2008 temps. I find this graph works well:

  32. ilajd says:

    McIntyre has a very timely new post up titled “The impact of Yamal on the Spaghetti Graph”. (Link below) I don’t know how much more specific you can get!

    “You will frequently see apologists state that these reconstructions provide “independent” evidence. However, this is not the case on two counts. The same proxies are used over and over again – a point reported at CA on many occasions and confirmed in Wegman et al 2006. Thus, if problems arise with (say) bristlecones or (say) Yamal, this will affect multiple studies and not be contained to one result. More on this below. In addition, there are not really 10 “independent” groups, as “independence” is understood in the real world. Mann and Jones 2003 is not independent of Mann, Bradley and Hughes (1998) or Jones (Briffa) et al 1998 or Rutherford et al 2005 (Mann, Osborn, Bradley, Briffa, Hughes and Jones). ”

    “In summary, the apparent problems with Briffa’s Yamal series impact multiple other studies:
    Briffa 2000, Mann and Jones 2003 (used in the recent UNEP graphic), Mann et al (EOS 2003), Jones and Mann 2004, Osborn and Briffa 2006, D’Arrigo et al 2006, Hegerl et al 2007, Kaufman et al 2009 (and of course, Briffa et al 2008).

    And because of the non-robust methods used in these studies, replacing the Briffa Yamal version with a more defensible alternative (such as Esper Polar Urals either individually or in combination with the subfossil Yamal data and Schweingruber russ035w in Yamal) is going to have a material impact on the medieval-modern differential.”

    Honestly for the sake of science its time to put this one to bed. Ove, will this change your view?

  33. ilajd says:

    Regarding Graph 7.

    “For every proxy that supposedly shows a MWP cooler than the present, there seems to be one that is just as good or better evidencing the opposite. For the California and Urals proxies so fundamental to the Hockey Stick, the ecological evidence is further evidence against the Graybill and Briffa chronologies being interpretable as temperature proxies.
    The selection of proxies in studies displayed by IPCC seems to me to be biased against proxies with a warm MWP. IPCC itself does not carry out any independent due diligence of the type that might be expected in a prospectus. Further, in 2007, as in 2001, the authors involved in preparing the paleoclimate section were active parties in controversies and, in the end, IPCC Fourth Assessment Report strongly reflects their partisan point of view.”

    Steve McIntyre From (p.39)

  34. Tim says:

    Anyone quoting wattsupwiththat or Pielke has got to be joking (and shows a clear lack of anything to do with accurate representation of data). You may as well be quoting and citing Plimer.


    Gavin Schmidt, Tim Lambert, Lambeck, Karoly, Breen and many, many others have debunked McIntyre, Watts, Pielke. Hell even Lomborg is seeing sense.

    What’s going to be truly funny is when the Bolt’s, Pielkes etc of the world are left shouting “Conspiracy, conspiracy” as the Good Ship Humanity goes down the plughole.


  35. Steve Bloom says:

    ilajd, writings from a retired (?) mining stock speculator and an economist are a notably poor way to get the attention of climate scientists. M&M are now saying to the media and politicians “Hey, that hockey stick we overturned five or six years ago is now even more overturned, so you should ignore all those scientists — not just MBH but the entire field of recent-past paleoclimatology — and pay attention to us!” Sorry, it’s passed its sell-by date. You’re not going to see much on it in the press, and I don’t expect it’ll even get featured at Copenhagen.

    FYI, you have the relationship between recent variability and climate sensitivity completely reversed. Finding more of an LIA/MWP increases sensitivity. Regarding what else do you have a fundamental misunderstanding?

  36. Ian says:

    John and Ove – If you choose to select the temperature record data “all’ from the box to the right of ‘history’ in the link…… you will see that the temperature at this station in central Greenland has been decreasing at an average rate of 0.99 degrees centigrade since the measurements commenced in 1983. I would like Ove to explain how this is in keeping with reports of shrinking glaciers (his graph 4 above) and a future ice-free Greenland. Surely it means that the Greenland glaciers and ice sheet are more likely to expand in future years if this trend continues.

    Ove – in my earlier post I noted links to sites which show that sea ice at both poles is at higher levels than in previous years. You responded with a link to a BBC news site informing that sea water temperatures were warming and this warm water was melting sea ice. As a climate scientist how do you explain to laypeople and your students how both these positions are correct?

    Also, I have been following Ilajg’s comments above and I would be very interested to learn why you are claiming that temperatures are at a ’1,000 year record’ as per your ‘graph 7′ above. Surely this graph is no longer scientifically valid or do you still consider the science behind the original work as sound?

  37. Steve Bloom says:

    A quick check of Google News bears out my hypothesis: A small amount of activity on right-wing blogs and sites, and not much else. Morano is flogging it heavily but so far Drudge seems uninterested.

  38. Ian says:

    Sorry correction to my last post… “an average rate of 0.99 degrees centigrade” should read “an average annual rate of 0.99 degrees centigrade”

  39. Ove Hoegh-Guldberg says:

    Iljad: It’d be too easy to write off the Climate Audit approach as more of the same from a mining stock speculator and an economist. McIntyre’s criticism is interesting – i’ll get back to you on this with a response in a separate post.

    Ian: According to the link, the Greenland data is from a single weather station (Uummannaq/qaarsu), 500km WSW of the center of greenland and 3007m in elevation. I wouldn’t expect a entire continent (2,166,086km2) to show a uniform trend in warming or cooling, the same as I wouldn’t take a trend from a single location and extrapolate it to an entire region. To expand on this point, take a look at the Pritchard et al. sea ice elevation graph mentioned in the previous post. It’s clear that there is variability across the continent – some areas are increasing (particularly to the centre of the continent), whilst some are losing ice at a vast rate (overwhelmingly at the edges of the continent).

    See here for published records of Greenland temperature between 1873-2001, and here for an article describing a NASA study of the entire ice sheet (not just a single temperature station) quantifying daily temperature changes between 2000-2006.

    What you term as recorded ‘increases‘ in Arctic sea ice in the last few years are still significant lower when compared to the 1979 – 2006 averages. This similar to the argument used by folks who say the world hasn’t cooled since 1998. I’d expect year to year variations in sea ice extent independent of the long-term trend, but this doesn’t detract from a long-term trend in decline in Arctic sea ice (see the National Snow and Ice Data Center for more information). As for the Antarctic, the NSIDC acknowledge the small decadal trend of 0.99% increase in overall sea ice cover, whilst at the same time noting intensified ice melt (loss of ice sheet thickness):

    “There’s been a change in atmospheric circulation around Antarctica related to the stratospheric ozone depletion and this actually causes stronger winds, which then pushes the ice away from the coast in some regions of Antarctica, which actually then causes more new ice formation and increases the overall sea ice in that region,” she said.

    “In other parts of Antarctica the temperatures have been decreasing and this is again sort of what we’ve expected to see, at least according to what the climate models tell us should be happening.

    “But if you look at the Antarctic Peninsula for example, that’s where you’ve had really strong warming and you’ve had a warming of about 3 degrees Celsius in the last 50 years.

    “And if you look at changes in sea ice in that region they all show very strong negative trends.

    “The paper shows an overall positive trend if you look at all of Antarctica, but there’s regional differences that are quite different from different regions.

  40. ilajd says:

    Look forward to your post Ove.

    By the way Re McIntyre’s expertise I guess it would be similarly lazy to right off your expertise as being in Marine biology, leaving you little room for commenting on palaeoclimate studies.

  41. David Horton says:

    Good heavens, this post turned out to be like flypaper for denialists! Or Andrew Bolt fans, I suppose, though I didn’t think he had this many.

  42. gravityloss says:

    There’s something fishy about that greenland data, the yearly averages drop 20 C around 1998 or so. Probably the dataset is not right, it changes station in the mean time or the first part is an anomaly and not temperature or something else…

    (click “all” here:

  43. David Horton says:

    Interesting that the “Yamal controversy” the latest piece of denialism flashing around the web ( is here as well. I reckon you have become a target Ove, so that means you are doing something right. But I am disappointed that this mob aren’t targeting my blog as well – I try to be really rude about them. Perhaps I should try being polite … no, can’t do it.

  44. Girma says:

    My friends, if you haven’t already noticed, please have a closer look at the following plots.

    Mean Global Temperature Anomaly Plot from Data from Hadley Centre
    (Linear warming of 0.44 deg C/100 years, with +/-0.45 deg C oscillation about every 30 years)

    Mean Global Temperature Anomaly Plot from Data from NASA Goddard Institute for Space Studies(Linear warming of 0.56 deg C/100 years, with +/-0.36 deg C oscillation about every 30 years)

    In both plots, look at the right end of the red anomaly curve for last year, 2008. Look also at the right end of the green linear warming line. In the coming years, will this red curve move towards the green line and cross it, or will it do a 180-degree somersault and move away from the green line to its maximum value before, and then beyond that maximum value?

    The theory of CO2 driven global warming will fall apart without this 180-degree somersault. We will watch, with intense interest, whether or not this somersault happens in the coming years. Unless that happens, the science is not settled.

    Based on historical patters, the anomaly pattern after 1998 matches that after 1880. If this pattern is repeated, we will have 20 more years of global cooling to anomaly temperature values similar to the 1970s, wiping out all the increase in temperature during the three last decades of the previous century.

    Note also that long before the automobile and air conditioning, from 1860 to 1890, for 30 years, the globe was warming at the rate of 0.41 deg C/100 years.

    In 1998, near the end of the last century, the oscillation component of the anomaly happened to be at its maximum; as a result, the increase in mean global temperature in the last century, from the Hadley Center data, was about 0.44 + 0.45 = 0.9 deg C. If the oscillation component of the anomaly were at its minimum (like 1911 or 1976) , there would not have been any significant change in mean global temperature (0.44-0.45 = -0.01 deg C) in the last century.

    Science is about the data. Science is not about consensus or authority.

    From the data so far, from the science, CO2 driven global warming appears to be baseless.

  45. J.Roff says:

    Girma: We’ve covered this before.

  46. Girma says:

    I don’t argue about the linear global warming of 0.44 deg C/100 years.

    At you can remove this linear trend by using a DETREND = 0.706, and see the pattern of the oscillating component of the anomaly for the last 150 years.

    Here is the plot with the linear trend removed that shows the oscillating component of the anomaly with variation of +/- 0.45 deg C.

    Cooling from 1878 to 1911, for 33 years

    Cooling from 1944 to 1976, for 32 years

    Cooling from 1998 to ? (2030, for 33 or 32 years)

  47. Robin Levett says:

    First time poster here – came over from Scienceblogs.

    @Ian (and also gravityloss):

    BGUQ appears to be the weather station at an airfield, Qaarsut airfield, built in 1999; on the west coast of Greenland – at an elevation of 2 metres…;showall=1


    Perhaps the elevation reported on the Wolfram site of 9865 feet below the centre of Greenland should have given Ian pause.

  48. clifton says:

    I wouldn’t get too hung up on debating obvious denier trolls Ian and Ilajd – they’ll just regurgitate junk science and never directly answer a question.

    A much better solution would be for Ian and Ilajd to come down to Melbourne to talk to the families of the dead from the January heatwave, and tell those families that heat was all normal and therefore their deaths were just healthy and normal too. Of course, like most deniers, they are too gutless to discuss the revolting temperatures and deaths that are now occurring – to them its all ‘normal’.

    The main thing is that the deniers get the full rich credit from the rest of us in a few years time when the results are clearly in. Boy, will people want to give them feedback! And, what could be more conservative than reaping the full, rich, credit for stopping any action on emissions. Any conservative would be proud to do so.

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