Clive Best – written submission to ECC select committee on AR5

This is a cross posting from Clive Best detailing the written submission he made to the Energy and Climate Change (ECC) select committee on the IPCC 5th Assessment Report (AR5) that was published last year (the link provides access to all written submissions).

Clive’s views and my own are quite well aligned on both climate and energy matters and I am grateful that he has taken time to read the report and to relate these measured views to the committee. His submission is short and to the point.

Submission by Clive Best

I am an independent scientist. I have a PhD in High Energy Physics and previously worked at CERN, Rutherford Lab, JET Fusion Experiment and the Joint Research Centre of the European Commission. All opinions expressed here are entirely my own.

The fifth assessment report is a comprehensive and impressive review of the current status of climate science. Although the message remains one of warning, the results are actually rather encouraging. The relevant new conclusions of AR5 are:

  1. The acknowledgement that up to half the observed warming since 1950 is due to natural effects.
  2. That climate sensitivity estimates have now been reduced. Manmade warming is likely to be less than 2C for a doubling of CO2 (560 ppm).
  3. The current pause in warming may well continue until 2030 due to a natural 60-year cycle in ocean dynamics (AMO/PDO) – see figure 1. Thereafter we can expect another period of rapid warming.
  4. All AR5 climate models overestimated warming till 2012 because they excluded this natural oscillation – see figure 2.
  5. The risk of climate disruption and extreme weather impacts is very small.
  6. Sea level rise is a modest 60cm by 2100. Sea defenses can easily cope with this.
  7. There will always remain uncertainties in climate models due to the complexity of climate interactions. As an example scientists still cannot model the dynamics of past glaciations nor predict when the next one will occur. Another ice age would be far more catastrophic than global warming.
  8. The largest model uncertainties are clouds. Clouds play the same role as the white daisies do in Lovelock’s daisy world.

In general AR5 is good news for the world and good news for the UK. The world has more time to adapt to a low carbon future than previously assumed. Professor Dieter Helm makes a strong argument in “The Carbon Crunch” for gas as a low carbon transition path. Other implications for UK energy policy are:

  • Carbon targets can be relaxed. Investment in new wind generation too quickly is counter-productive as costs begin to outweigh benefits above 20% intrusion on the grid [1].
  • More resources could then be invested in research and development on future technologies. For example:
    • Energy storage
    • Next generation solar, artificial photosynthesis
    • Compact nuclear, thorium reactors
    • Nuclear fusion, hybrid fusion/fission

Overall fit to 162 years of global temperature data

Fig 1: An overall fit to 162 years of global temperature data

Fig 2: Comparison of CMIP5 models and observed temperature trends.

Fig 2: Comparison of CMIP5 models and observed temperature trends.


1. A cost Benefit Analysis of Wind Power, Eleanor Denny, PhD. Thesis , 2007 University College Dublin.

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26 Responses to Clive Best – written submission to ECC select committee on AR5

  1. Willem Post says:

    You asked about a reference for the climate cycles of the past 10,000 years. Here is an excerpt from my article and the reference.

    The current ice age started about 2.5 million years ago and has NOT ended. Ice ages have melting (warming) periods and cooling (glaciation) periods. The melting phase of the last major glaciation period began about 15,000 years ago. Before the melting started the WAT was about 11.5 C.

    By about 10,000 years ago, this melting phase had ended, ice sheets that were about a mile thick had mostly melted, i.e., shrunk in surface area and thickness, rocky surfaces, bolders and sand layers were exposed and top soil could eventually begin to form as fauna and flora spread to these areas.

    During the past 10,000 years, there have been 7 warming periods with increasing WATs and 7 cooling periods with decreasing WATs. During the two Holocene Climate Optima (warming periods), 8,000 to 6,000 and 4,800 to 3,600 years ago, the WAT peaked at about 16 C; some areas were 1.5 C to 5 C warmer than the WAT, others cooler.

    During the RWP, the WAT peaked at about 15.7 C
    During the MWP, the WAT peaked at about 15.6 C.
    During the PWP, it is about 15.5 C.

    Between the RWP and the MWP was a moderate warming period that coincided with the Dark Ages.
    Between the MWP and the PWP was the LIA from about 1450 to 1850.

    Note: LIA is a misnomer, as it was merely a glaciation period within the present ice age.

  2. Roger Andrews says:

    First, congrats to Clive on a fine submission. I hope it and others like it make a difference.

    Whether they will, however, remains to be seen. The problem is this. What would happen if the IPCC admitted that they really didn’t have any idea how the Earth’s climate works and no good evidence that man-made emissions were having any impact whatever on anything? More than a few prominent politicians would be out of office, thousands of bureaucrats would be out of a job, thousands of scientists could wave bye-bye to their research grants, wind and solar companies would be filing for bankruptcy, carbon traders would have to find new employment and the whole $1 billion-a-day climate change industry would go down the tubes, So don’t expect any quick breakthroughs.

    • Euan Mearns says:

      Roger, a few years ago now I actually gave a talk at UK MET Hadley. Extremely well attended and received. This was post CRU email, charm offensive in full bloom. I was told then if warming didn’t resume in a couple of years, AGW and they were stuffed. It appears not to be the case 🙁

      Discussing this with son Duncan walking dogs this pm he pointed out that for science to be science requires a falsifiable hypothesis. So what is the falsifiable hypothesis for AGW or CAGW? They have managed to get away with 15 years with no lower troposphere warming and to blame the arctic vortex freezing of N America on “climate change”. What evidence would prove “the consensus” to be unproven?

      • Roger Andrews says:

        Euan: You’ve put your finger on the difficulty. How can you falsify a theory that projects what’s going to happen a hundred years or more into the future? You can’t, unless you have a time machine handy. You either believe it or you don’t.

        However, we can gauge the reliability of the projections by seeing how well the climate models that are used to make them replicate historic temperature observations. And the answer is; they flunk, although the IPCC doesn’t want anyone to find out about it. Details below:

  3. A C Osborn says:

    Roger Andrews says: January 13, 2014 at 5:32 pm

    Roger, it is getting closer to them having to own up all the time, they have scaled back their best guess on the results of Climate Sensitivity in the future and are no longer using the Model Outputs and openly admit in their latest summary that they they don’t know what the actual Climate Sensitivity is.

  4. Richard Miller says:

    Some thoughts.

    1. The trouble with expressing a probability between two outcomes is that either outcome may occur, and you still don’t know how accurate your probabilities were.
    2. The Derby paradox: suppose 30 horses run the race. Suppose the favourite is running at 3:1, and suppose that all odds reflect a horse’s chances of winning. Which horse is most likely to win? The favourite. What’s the most likely result? That the favourite loses.
    3. Figure 1 does not convince me that warming has gone away, not by a very long chalk.

    • Roger Andrews says:

      Well, what would it take to convince you that the warming has gone away?

    • Euan Mearns says:

      Richard, for a number of years I have expressed the view that late 20th C warming was likely a combination of human and natural cyclic activity (and have been vilified for this). A natural consequence of this that most geologists (like you) can do in their head is that climate sensitivity is likely at the low end of IPCC scenarios (even though the MET office needs a huge black box that I’ve seen), most folks can do this on a Casio calculator (1/2 = 0.5).

      Clive says:

      The current pause in warming may well continue until 2030 due to a natural 60-year cycle in ocean dynamics (AMO/PDO) – see figure 1. Thereafter we can expect another period of rapid warming.

      I agree in part with this but do not know what the distribution of probabilities are – those who have received billions in funding should ideally be able to tell me! At some point very soon the DO – Bond cycle may turn, and it could overwhelm the anthropogenic signal. Or maybe we go back into natural warming reinforced by AGW.

      • Clive Best says:

        There is a simple argument as to why feedbacks cannot be positive(linear) based on the faint sun paradox. The sun is a main sequence star whose brightness evolves with age. 4 billion years ago geological evidence shows that liquid oceans existed on earth when radiant energy from the sun was 30% less than today. Only a negative feedback from water can explain why the oceans haven’t boiled away eons ago – see below.

  5. clivebest says:

    I think the falsifiable hypothesis will be the prediction of a positive H2O feedback. If this can be shown to be false (water vapour and clouds) then global warming is no big deal.

    One specific prediction which has been falsified is the hotspot in the upper tropical troposphere expected due to enhanced evaporation in models. I suspect the next one will be clouds. If net cloud cover is shown to have increased then the models are wrong.

    The Sherwood paper is an attempt to bolster high sensitivity models but it has very dubious evidence which doesn’t even convince the readers of realclimate.

    • Roger Andrews says:

      Clive: The difficulty there is that every climate sensitivity estimate greater than one implies some kind of positive feedback, and there are very few estimates from either side of the fence that give a value of less than one.

      The problem with climate sensitivity estimates, however, is that they all assume that CO2 contributed to the temperature increase. The results are a) a relationship between CO2 and temperature is always detected and b) that natural forcings often get counted as CO2.

      • clivebest says:

        We have to home in on what if anything the problem is:

        Is CO2 a greenhouse gas ? – Yes
        Are we emitting more CO2 than 1000 years ago? – Yes
        Is it a problem we need to address immediately? – Probably Not and certainly not for the UK
        Do we need to do something before the price of fossil fuel drive a switch to alternatives? Only if climate sensitivity > 2C.

        The climate change act 2008 and vested green interests are ruling out the last two choices and will resort to non scientific means to defend their turf.
        So we have to prove that there is no real problem in the long term. This is not easy.

        • Roger Andrews says:

          It’s not easy. It’s impossible. There is no way of conclusively proving that CO2 won’t have fried the Earth by AD 2300 any more than there is of conclusively proving that the Earth won’t get annihilated by an asteroid a hundred years from now. The future scares people, and the Greens know it.

          That’s why I’m beginning to think that the only solution is political. My hope is that after a few years at current rates of progress even the dumbest politicians will begin to realize that we can’t cut emissions without severely damaging the economy, whereupon they will start to look for reasons not to have to cut them. That’s when the “science” will begin to come under scrutiny.

  6. Steve Fawkes says:

    The submission is an excellent summary and the subsequent posts are all really useful. This is exactly the kind of discussion we should be having about climate and energy futures. It seems that the current government has shifted to a more realistic position but of course they find it very difficult to admit that their previous position was wrong. They also still want to present single technologies as “the answer” to complex energy problems – last month new nuclear, this month shale gas.

  7. JamieB says:

    Can someone please help me here because I’m struggling to match some of Clive’s “relevant new conclusions of AR5” with what AR5 itself says.

    CB: The acknowledgement that up to half the observed warming since 1950 is due to natural effects.

    Comment: Yes it does say this but if you look at the numbers it reveals a considerably more nuanced view than the casual reader of this point might take away from this statement. What the SPM says is:

    “Greenhouse gases contributed a global mean surface warming likely to be in the range of 0.5C to 1.3C over the period 1951 to 2010, with the contributions from other anthropogenic forcings, including the cooling effect of aerosols, likely to be in the range of -0.6C to 0.1C. The contribution from natural forcings is likely to be in the range of -0.1C to 0.1C, and from natural internal variability is likely to be in the range of -0.1C to 0.1C.”

    So there’s an outside chance that if the actual values are at the ends of our error bands then they could account for up to half of the warming but essentially natural effects probably account for close to zero of the observed warming trend.

    CB: That climate sensitivity estimates have now been reduced. Manmade warming is likely to be less than 2C for a doubling of CO2 (560 ppm).

    Comment: It’s correct to say that the lower bound of ECS has been reduced (the upper has remained the same) but the SPM says that “equilibrium climate sensitivity is likely in the range 1.5C to 4.5C (high confidence), extremely unlikely less than 1C (high confidence), and very unlikely greater than 6C (medium confidence)”. So it’s not concluding that warming is likely to be less than 2C, it’s concluing that it’s likely to be 1.5C to 4.5C.

    CB: The current pause in warming may well continue until 2030 due to a natural 60-year cycle in ocean dynamics (AMO/PDO) – see figure 1. Thereafter we can expect another period of rapid warming.

    Comment: Can you please point out where it says this because I can’t find any reference to this.

    • Euan Mearns says:

      Thanks for your comment, I’ve sent an email to Clive asking him to respond. He may well be away from his desk for the day.

    • Clive Best says:


      Let me try and answer your points.

      1)CB: The acknowledgement that up to half the observed warming since 1950 is due to natural effects.
      This is based on the following statement in SPM.

      It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together”

      This essentially states that with 5% probability half of the observed warming is due to natural causes. Therefore I use the phrase “up to half” of observed warming could be natural.

      2) CB: That climate sensitivity estimates have now been reduced. Manmade warming is likely to be less than 2C for a doubling of CO2 (560 ppm).

      What really matters for policy makers is TCR, because when in ~2090 CO2 reaches 560ppm it will be the temperature rise then that will determine public response. This figure will indeed very likely be less than 2C based on the latest measurements by OTTO et al. and on the estimates in the IPCC AR5. ECS on the other hand means waiting for another 50 years to see how the climate stabilizes, but that is an impossible thing to do because CO2 and the climate is always changing. In addition the real uncertainties in the models are for the values of feedbacks – particularly clouds and not climate sensitivity. These are measured in Watts/m2/deg.C ± error. The temperature response however is not symmetric with feedback and is skewed to high sensitivities – hence the extreme top ends values. The most likely value is always nearer the low end – so even ECS is “likely” ~ 2.5 deg.C.

      3) CB: The current pause in warming may well continue until 2030 due to a natural 60-year cycle in ocean dynamics (AMO/PDO) – see figure 1. Thereafter we can expect another period of rapid warming.

      OK – youv’e got me there! This is not explicitly written in AR5 but instead it is my interpretation of the global temperature data. There have also been several papers by Nicola Scappeta, and many other observers have reported on the 60 year oscillation apparent in the data. To understand what I am talking about you can look at for example
      A fit to global temperature data. The predicted trends for different scenarios are shown here. They show a flat temperature response till 2030.

      The comments about energy policy are also in the same vein – informed opinion.

      • JamieB says:

        Thanks for the response Clive.

        1) You missed out the important bit from that quote: “The best estimate of the human-induced contribution to warming is similar to the observed warming over this period.” i.e. the best estimate is that natural forcings and internal variability are close to zero and that anthropogenic GHGs and aerosols account for all of the observed warming.

        I find it odd that the IPCC used those words as one of the lead statements in the first place as it’s quite open to misinterpretation. It was probably their conservative approach and the nature of the IPCC process that led to it.

        2) Point taken about ECS vs TCS (although personally speaking I’m more concerned about what we’re lumbering humanity and our ecosystems with in the coming centuries than the coming decades, but I appreciate there are still considerable uncertainties when looking out that far).

        3) I find it more than a little concerning that you presented this point as a “relevant new finding” of AR5 in your submission.

        • Euan Mearns says:

          3) I find it more than a little concerning that you presented this point as a “relevant new finding” of AR5 in your submission.

          I agree and also accept I should have been a bit more careful verifying Clive’s points. But blogging and this form of peer review serves its purpose well. I think when Clive began by saying…

          The fifth assessment report is a comprehensive and impressive review of the current status of climate science.

          …about a report that I dare say he has extensive disagreement with that he has got lost between what the report actually said and what he feels it should have said. But to move on, I think discussing the Nature report is far more important.

      • clivebest says:


        Nature has just published a report which confirms my point 3. The 60 year cycle is due to changes in ocean heat dynamics. This conclusion is supported also by Kevin Trenberth and NCAR. Therefore models which do not include this natural waring from 1970-2000 have over-estimated climate sensitivity


        and in particular look at this graph

        So even though it was not explicitly written in AR5, IPCC scientists have now confirmed it.

        • Euan Mearns says:

          Clive, thanks for the link. I did a course on climatology at University of Aberdeen about 37 years ago and learned then that The Pacific Ocean controlled Earth’s climate. It is therefore incredible that climate science is only just awakening to this reality and to the reality of natural cycles. Accepting the Nature report as “fact” has consequence that all climate models are wrong (we knew that already) and their replication of past climate change as “fraud” – basically tuning variables to produce the desired outcome and calling it science. Without including natural cycles they can have no predictive power.

          The PDO 60 year oscillation is only one of a number of natural cycles that climate models currently lack. A more important one is the 1000±500 year Bond / DO cycle. IF the Bond 2001 data are reliable (and they are contested) then what they describe is periodic ingress of the Labrador current into the N Atlantic and this truncates the Gulf Stream correlating with cold periods in NW Europe. A simplistic view of the consequence would be less evaporation from the Gulf Stream in the N Atlantic leading to reduced GH warming and regional cooling.

          I discuss some of this in The Ice Man Cometh and a modified version of the key chart showing Bond cycles is here.

        • Roger Andrews says:

          I claim prior rights on this one:

          And Bob Tisdale came before me:

          Ninety-nine point something percent of the heat in the atmosphere and the oceans is in the oceans, and as Euan points out the dominant influence of ocean cycles on the Earth’s climate has been known about for at least 37 years. It’s good that the Team have finally found this out for themselves, but a pity that they’re using it as yet another ad-hoc explanation for the warming “hiatus”, as they call it. If they dug into the data a little deeper they might find that ENSO cycles can in fact explain ALL of the recent warming.

          • Euan Mearns says:

            Roger, thought you had fallen asleep under your palm tree 😉
            Mass of oceans = 1.4*10^21 kg (actually mass of hydrosphere)
            Mass of atmosphere = 5.15*10^18 kg

            So the oceans are 272 times more massive and contain 99.6% of the of the combined mass of atmosphere and hydrosphere. Trying to warm the oceans from a GHG warmed atmosphere would be like trying to warm a rock using a feather. I’m guessing principle mechanism for warming the oceans is direct sunlight absorption that will vary over time with dCloud.

            It seems blindingly obvious that with all the mass the oceans can easily warm the atmosphere. Just change the way they are stirring a bit, put some warm (or cold) water in the “wrong” place and you will get weather change.

  8. JamieB says:

    Thanks Euan.

  9. Roger Andrews says:

    Sleeping under a palm tree? Perish the thought. I’m actually busy working with an interactive spreadsheet that predicts when the lights are going to go out in UK. Stay tuned 🙂

    I’m working on clouds too, but that’s a little tougher.

    While I’m here I will add that unlike its three predecessors the 2010/11 Niño/Niña combination has not caused a stair-step increase in surface temperature, suggesting that the oceans have indeed run out of surplus heat.

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