David Henderson questions today’s received opinion on climate change

This is a very readable and concise summing up of reasons to be skeptical of the IPCC. I have converted David Henderson‘s speech to an html page here

[Note by WSH, this post re-written 24 May. The webpage speech of David Henderson is unchanged]


David Henderson recently commented on a major presentation by Professor Mohan Munasinghe, a Vice-Chair of the IPCC. He argues that today’s received opinion on climate change issues incorporates three mutually reinforcing and unwarranted

  1. That the official policy consensus, as widely interpreted today by governments and international agencies, mirrors prevailing scientific opinion and goes no further than it would warrant.
  2. That prevailing scientific opinion must now be viewed as no longer open to serious question.
  3. That the process of review and inquiry from which prevailing scientific opinion has emerged, and in particular the IPCC process as its leading element, are professionally above reproach.

In his view, all these beliefs are unfounded. They show a lack of awareness respectively of the present extent of overstatement, overconfidence, and ingrained bias.

Not for the first time, Henderson draws attention to the failure on the part of treasuries and finance ministries across the world to treat climate change issues in an inforrned and resourceful way.

4 thoughts on “David Henderson questions today’s received opinion on climate change”

  1. Off Topic

    Warwick: If you haven’t seen this, here’s an alternate theory for anomalous Siberian warming. It’s from comment 15 at this post at ClimateAudit:

    “This thing with the SSTs reminds me of the revelation after the Cold War that in many Russian cities, mayors or other local leadership would have their ‘offical’ daily temperatures exaggerated in order to make it look as if it were really colder than it was, in order to get more money for fuel from Moscow. After 1990 we see a sudden jump in Siberian temperatures-coincidence?”

    Interesting. I wonder if he has anything hard to back it up.


  2. Warwick, I noticed something odd. You see the net inflow/outflow of Perth dams at the link below. Yesterday, June 10 to 11, there was a net outflow of 720 million liters. This is substantially larger than the total water consumption from the dams, about 500 ML, at this time of year.

    It rained some yesterday and there was heavy rain the day before, shown by the large net inflow the previous day (1500 ML). This should have led to substantial inflow yesterday.

    The numbers just don’t add up. On the face of it, over 1000 megaliters (and I’d say more like 15000 ML) has just gone missing.


  3. Until WaterCorporation publish say a detailed monthly water balance on its website we will never know what is contributing to dam levels changes. I have read that production from the Kwinana desal plant is stored in Canning dam. There can also be transfers between dams, from the south plus transfers to he Kalgoorlie pipeline. In order to know what catchment runoff is contributing to dam levels, it is essential to have a tally of all these other transfers.
    Open and transparent.
    Not likely.

  4. Dear Sirs/Ms

    Below is the official explanation of the UK Governments policy on climate. I am extremely concerned by it articulately as the world is now cooling, according to the Heartland Institute Scientists and NASA has apparently recently announced that it cannot find any evidence of AGW and has also admitted that the NASA satellite temperatures have been 15 degrees overstated.

    I would like some help with my response please.

    I notice, for example, that hedge funds are buying up enormous tracts of arm land in anticipation of the world not being able to grow sufficient food.

    My MP, Jeremy Hunt has a totally closed mind about these matters which worries me greatly

    Scientists (palaeoclimatologists) studying the Earths historical climates are sure that the climate varies on all time scales, ranging from years to millions of years and more caused by factors including plate tectonics (causing the redistribution of oceans and continents), meteorite impacts, changes in volcanic activity, changes in the Suns activity and variations in the Earths orbit around the Sun.

    However, the pattern and pace of warming observed since the start of the twentieth century is highly unusual world-wide warming of this type has probably been unprecedented in at least the last 1300 years.

    The pace and pattern of this current warming has been compared to that expected to result from all natural factors known to change the climate in the past and none of them – such as changes in the Earths orbit, volcanic or solar activity – can account for this warming. In contrast, rising greenhouse gas concentrations explain the warming convincingly.

    The physical properties of these gases in the atmosphere have been understood for more than a century they are known to trap outgoing radiation, warming the Earth. Since the Industrial Revolution, humans have raised the levels of these heat-trapping gases; by around 38% for carbon dioxide. This gives a very convincing explanation for most of the warming observed (around 0.75C) in the past century.

    Human activities are increasing the levels of CO2 and other greenhouse gases in the atmosphere.
    Burning fossil fuels, other industrial processes, clearing forests and other agricultural practices are major contributors to CO2.
    CO2 levels in the atmosphere have gone up 38% since pre-industrial times, to 387 parts per million today.
    Ice cores show that CO2 concentrations are now at their highest level for at least 800,000 years (and probably much longer).
    Carbon dioxide produced from burning fossil fuels has a distinct chemical fingerprint (isotopic ratio). Scientists have seen a change in this ratio through time showing that the increasing concentration of greenhouse gases in the air can be linked to human activities.

    Ecosystems are finely adapted to local climatic conditions. As human activities are forcing global temperatures to rise, these climates are already beginning to change.

    At low levels of temperature rise, warming is predicted to have some positive impacts in some places, and negative impacts in others. However, as warming increases and particularly if it exceeds 2C any benefits are predicted to drop off sharply, with negative impacts projected for global food production, fresh water availability and vulnerable ecosystems.

    Ecosystems (and people) can adapt to changing climates but the more quickly warming happens, the harder (and more costly for human communities and societies) it will be to adapt effectively. Limiting warming is also vital to manage and reduce the risk of triggering potentially dangerous, rapid or irreversible changes to the climate system.

    For these reasons, the UK and as part of the Copenhagen Accord – has committed to a goal of preventing warming exceeding 2C above pre-industrial levels.

    The instrumental mean surface air temperature record is the primary evidence that the Earth has been warming since the end of the 19th century. The two main versions of this record are produced by the Goddard Institute of Space Studies (part of NASA) in the USA and the Climatic Research Unit/Met Office Hadley Centre in the UK, though the IPCC additionally cite two other surface temperature records in their recent Fourth Assessment Report (AR4). These datasets are subject to stringent quality control procedures , but it is not possible to completely eliminate errors and uncertainties from the data, which tend to increase the further back in time one goes. In general, taken over a century, the cumulative error in the data is approximately an order of magnitude less than the total temperature change over this period. Shown below is the UK dataset with uncertainty estimates shown by the grey bars.

    The marked slowdown in the rate of warming between 1998 and 2007 (about 0.04C/decade compared with 0.17C/decade over the last 30 years is the result of intrinsic variability arising from the many physical elements in the climate system. This means that mean global temperature does not rise smoothly in response to the steady increase in radiative forcing from accumulating greenhouse gases in the atmosphere. Over decadal intervals, the response amplitude from natural climate variability can be greater than the long term warming trend from greenhouse gas increases, resulting in some years with little or no warming and other years with very rapid warming. This behaviour is entirely consistent with scientific understanding of natural fluctuations of the climate within a trend of continued long term warming. Also, the fall in global temperatures over the past three years is not significant because it has happened several times before, as can be seen by inspecting the red bars in!
    the above graph.
    The cooling effects of the strong La Nina conditions that recently prevailed in the Pacific has now given way to an emerging El Nino (which tends to warm the climate), after which global temperatures are expected to resume trending upwards and re-attain the long term warming trend. The point to note is that over short term intervals natural climatic variations can temporarily mask the long term warming effects of rising greenhouse gas concentrations.
    Now that we know the Earth is warming, the cause must be identified. While useful, CO2 time histories derived from ice cores and hockey stick type graphs of past temperature variability are not in themselves sufficient to claim human activities are warming the climate, though they do contribute to the evidence that climate change is happening. The formal process of identifying a link between human greenhouse gas emissions and rising global temperatures is known as detection and attribution.
    Put simply, a climate change is detected in observations if its likelihood of occurrence by chance due to internal variability alone is determined to be small. This has been shown to be the case for the temperature fluctuation since 1900 shown in the above graph. Attribution is the process of identifying which of the likely climatic forcings (changes in greenhouse gases, aerosols, ozone changes, solar variability and volcanic eruptions) causes a climate response most consistent with the observed response. An application of a statistical method called optimal detection analysis, in which the spatial and temporal model calculated global warming patterns for each of the above climate forcings is matched to the observed warming pattern, results in a climate response amplitude to each of the likely climate forcings. The contribution to the mean global surface air temperature from the various forcings over the past 50 years can be derived from such an analysis and is shown in!
    the following graph . This graph is the basis of the IPCCs often quoted statement in the AR4 Summary for Policymakers that most of the observed increase in global average temperatures since the mid 20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.

    In the above graph, for the period 1950 to 1999 red is the estimated contribution from greenhouse gases, green is that from other anthropogenic such as aerosols and blue is the estimated contribution from solar variability and volcanic eruptions. The horizontal black line is the observed temperature change.
    In the above attribution analysis changes in solar irradiance was the only solar activity index considered. There have been conjectures that solar variability might also influence climate in other ways, e.g. the cosmic ray flux affecting Earth (the strength of this flux being controlled by the solar magnetic field) modifying global low cloud cover, but there is no hard evidence for this effect. In any case, since about 1985 all known solar activity indicators have been trending in a direction opposite to what one would expect if solar activity was the dominant cause of the warming trend over the past 30 years. (See Lockwood & Frhlich, 2007, Recent oppositely directed trends in solar climate forcings and the global mean surface air temperatures, Proc of the Royal Society A).
    Having established a likely dominant human influence on the present climate, information on how this might affect future climate, if greenhouse gas emissions continue to increase, can only be obtained from climate model projections. Scientists have considerable confidence that climate models can provide credible quantitative estimates of future climate change. This confidence stems from the foundation of the models in known physical principles, their ability to simulate important aspects of the current climate, the accurate reproduction of the global temperature trend over the past century when both human and natural factors that influence climate are included, and the ability of models to reproduce the main features of past climates such as the last glacial maximum (See chapters 6 and 9 of the IPCC Report on the Physical Science Basis of Climate Change).
    The models calculate that if CO2 is doubled in concentration from pre-industrial to 560ppm (very likely to occur during this century), the mean global temperature will increase by a value between 2 and 4.5C, possibly higher depending on the future behaviour of the oceanic and vegetation carbon sinks which are not well understood at present. The upper end of this temperature range is comparable to the warming that occurred following the end of the last ice age which resulted in massive changes to the Earths surface geography. However, that warming took place over a few thousand years, whereas the CO2 warming is projected to occur over one to a few centuries, thus imposing severe stresses on global ecosystems.
    The Working Group II contribution to the IPCC AR4, on Impacts, adaptation and vulnerability suggests that the severity of the impacts of climate change on such sectors as global ecology, food supply and water resources progressively increase the further global temperatures rise above 2C relative to pre-industrial. To minimise the risk of this happening, substantial reductions in global greenhouse gas emissions are imperative. The independent (of Government) Committee on Climate Change led by former CBI Director Lord Adair Turner recommended to the Government (which it has accepted) that the UK reduce greenhouse gas emissions by 80% below 1990 levels, having judged that it was a fair contribution to a future global climate deal and that it could be achieved without compromising the UK electricity supply. The Committees report can be read at www.decc.gov.uk .
    Assertions that the IPCC Reports (or indeed other sources of information the Government uses) are politically edited is a myth promoted by various sceptic web sites who, unable to discredit the science, try to discredit the organisation. The Assessment Reports, including the summaries, are written solely by reputable scientists. The UK Government fully supports the work of the IPCC.
    In October 2007, Sir Nicholas Stern, former chief economist at the World Bank, published his Review for the UK government on the Economics of Climate Change. The Stern Review stated that the scientific evidence was now overwhelming. This Review is another of the Governments key documents on climate change. However, a number of responses to and critiques of the Stern Review have been published. Many of them contain basic errors and misunderstandings, and the Stern team have already provided robust responses to these – with documents published on their website. They are also working on a final paper that will discuss many of these critiques. Government fully supports the team in these efforts. We think it is important for an independent Review of this significance to be discussed in the public – and many critiques have helped to build on, illuminate or explore particular areas of the Review and its recommendations.
    However, the careful sensitivity analysis the Stern team have done since the Review was published demonstrates clearly that the basic message of the Review withstands these critiques – that there is a need for an urgent and scaled-up response to the challenge. We agreed with that at the Review’s launch, and still do.
    In conclusion, we believe the Government’s responses to global warming is proportionate to the level of clear, repeatable and verifiable scientific evidence that is currently available.

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