Global Warming's Pause For Thought

by | Oct 22, 2009

Stu has an article up on Spiked about the reaction to Paul Hudson’s BBC article ‘What Happened to Global Warming?’:

A BBC News journalist’s willingness to report more than climate orthodoxy should be encouraged not condemned…

While we’re on the subject, it’s strange that no one seems to have mentioned the far more pronounced temperature plateau/decline that occurred between the mid-1940s and the early 1970s. The orthodox explanation for that one is that the cooling effect of white aerosols such as sulphates – released from coal and oil burning – was masking the warming effect of greenhouse gases until various clean air acts allowed the anthropogenic warming trend to re-emerge.

We wrote last year about how alarmists have wielded the aerosol-masking theory to beat down anyone who suggests that the post-war slump is a problem. Here’s George Monbiot:

Temperatures declined after the Second World War as a result of sulphate pollution from heavy industry, causing global dimming. This is well-known to all climate scientists. The exclusion of this information from [The Great Global Warming Swindle] was straightforward scientific dishonesty.

For Bob Ward, the Swindle‘s omission represented one of ‘five major misrepresentations of the scientific evidence’ in the programme.

The Independent’s Steve Connor also made a meal of it:

The programme failed to point out that scientists had now explained the period of “global cooling” between 1940 and 1970. It was caused by industrial emissions of sulphate pollutants, which tend to reflect sunlight. Subsequent clean-air laws have cleared up some of this pollution, revealing the true scale of global warming – a point that the film failed to mention.

The trouble is that there remains little empirical evidence to support the idea, as we were surprised to find out when we talked to UC San Diego atmospheric physicist Veerabhadran Ramanathan about his research showing that another type of aerosol – black carbon – had a significant warming effect:

Climate Resistance: What are the implications of this work for the idea that the post-war temperature decline is the result of sulphate aerosols masking the warming effect of CO2 emissions?

Veerabhadran Ramanathan: After the 1970s, when the West was cleaning up pollution, there was a rise in temperatures. We stopped burning coal in cities etc, and coal puts out a lot of sulphates, and sulphates mask global warming. At the same time, in the tropics, China and India, they were growing fast and putting a lot more Black Carbon.

CR: So the sulphate component must have been reduced more than the Black Carbon component for the aerosol masking theory to hold? We now need empirical data to compare the effect of black and white aerosols during the post-war temperature slump?

VR: Exactly.

CR: Do we have that empirical data?

VR: No. The data we have is for 2002-2003. We don’t know what happened in the ’50s, ’60s and ’70s. The implication of this study is that we have to understand what is the relative change in the sulphur emissions versus the Black Carbon emissions – and we don’t know that.

CR: So what is the empirical evidence that, 50 years ago, white aerosols were masking GW due to CO2?

VR: It’s pretty flimsy. The main information we have […] is our understanding of the SO2 emissions by coal combustion, and oil. But we need to know not so much how much SO2 we put out, but how much was converted to sulphates, how much was removed [etc]

CR: So you don’t even know the life cycle of the SO2 and sulphates?

VR: No. All the information we have is from models… It could still be true [that white aerosols account for the post-war temperature slump]

CR: But it could not be true?

VR: Yes. The picture is complicated. But this paper is not saying it is wrong[…]

CR: So we now have a better idea of what is happening aerosol-wise in the present, but what was going on in the 1950s/’60s is still elusive?

VR: Yes, There’s a lot of research needs to be done on that – what happened in the ’50s and ’60s, and then why the rapid ramp up [from the ’70s]. I’m not saying our current understanding is wrong, just that it is a more complicated picture. I would say it’s uncertain.

We wouldn’t suggest the aerosol-masking theory is wrong either. What’s interesting is how a neat idea is sold as an established fact, how a working hypothesis has become a truth ‘well-known to all climate scientists’, how ‘scientists are investigating’ becomes scientists ‘have explained’. Without the masking theory, the orthodoxy would have a serious problem. The research that shows that decade-long periods of static/declining temperatures are to be expected against the background of a warming trend (see the Spiked article above) makes no claims that such natural variation could account for the much longer post-war slump.

Meanwhile, it will be worth watching to see how the tactics of the climate orthodoxy change as – and if – the present slowdown in temperature rise continues. The slump has already robbed the orthodoxy of much of its potential for short-term alarmism about record temperatures, and the Met, for example, seems already to have ditched its yearly climate forecast in favour of a decadal one. And how long before serious efforts are made to explain the slump in causal terms – not to mention how quickly those investigations are deployed as proof that climate science has nailed it?


  1. Douglas Hoyt

    There were lots of studies of atmospheric transmission (and hence aerosol optical depth) starting with the work of Marvin and later Hand of the National Weather Service. Their papers can be found in Monthly Weather Review. Measurements start around 1880 and continue to 1940. They show no trends in atmospheric transmission except for volcanic eruptions.

    There have been a number of other studies along the same lines and they are referenced in a paper of mine (Hoyt, D. V. and C. Frohlich, 1983. Atmospheric transmission at Davos, Switzerland, 1909-1979. Climatic Change, 5, 61-72). This paper shows no changes in atmospheric transmission except for the occasional volcanic eruption. The measurements were made in central Europe where the GCMs claim the largest long-term aerosol changes occurred. The input to the GCMs are themselves modeled values (e.g., Charlson, 1991).

    Thus, the case for the cooling from 1940 to 1970 being caused by increased aerosols is not supported by the available measurements.

  2. geoffchambers

    Thanks to Douglas Hoyt for providing the science which justifies your scepticism. As you say:
    “What’s interesting is how a neat idea is sold as an established fact, how a working hypothesis has become a truth ‘well-known to all climate scientists’, how ’scientists are investigating’ becomes scientists ‘have explained’.”
    In other words, this article is not about the science, but about the reporting of the science by Monbiot of the Guardian, and Connor of the Independent, who will cite any ad hoc comment by a scientist which counters a sceptical argument, as if the simple fact that it is uttered by a scientist demolished the sceptical argument. The Global Warming Religion is moving from faith in Holy Writ to a doctrine of Papal Infallibility.

  3. artwest

    If the current slowdown continues or temperatures drop I’d expect alarmists to go, as a Plan A, for the Y2K excuse, “all our vastly-expensive work averted disaster”, (despite the fact that countries or organisations which did nothing suffered few or no ill-effects which weren’t easily fixed). For the Y2K alarmists it largely worked. They are still in lucrative employment and none were hanged from lampposts or bankrupted by lawsuits. Apart from the odd wry jibe in the media, they got away with it and with their pockets well-lined.

    As you say, if some serious carbon-reduction measures happen then that will make any climate/YK2 excuse slightly more plausible to the uninformed.

    Plan B, or an addition to Plan A, I’d expect to be the hyping of an “even more urgent” problem to deflect attention from the “problem” which wasn’t. The ramping up of Climate alarmism certainly made Y2K old news pretty fast.

    Whatever happens, unless there’s a perfect storm tipping point with a smoking gun and a non-partisan, credible, crusading political, scientific, media or legal entity pushing for the truth I’m afraid there may not be a real accounting for even the most fraudulent climate alarmists.
    The trouble is that such a crusading entity is unlikely to be one which is tainted by alarmism itself as they would have too much to lose, or be so politically extreme as to lack credibility with most of the public.

    Sadly, it’s difficult to imagine what or where that entity would be.

  4. George Carty

    China is currently suffering from horrendous air pollution caused by its huge numbers of coal-fired power stations.

    I’m surprised that these aerosol hasn’t been blamed for the falling temperatures in the last decade, just as Western coal- and oil-burning was blamed for the 1940-through-1970 global cooling…

  5. Douglas Hoyt

    There have been some regional aerosol clouds due to mankind’s activity. One them occurred in Great Britain starting with the Industrial Revolution. Its areal extent can be seen by examining W. F. MacDonald’s Atlas of Climatic Charts of the Oceans, published in 1938. These charts show a cloud of haze in the North Sea extending almost to Norway which is certainly due to coal burning. There are many accounts of these aerosols, perhaps the most famous being the London fogs. MacDonald’s atlas shows 12 other aerosol clouds all being downwind from desert regions and likely natural. The most famous of these dust clouds is the one blowing off the Sahara.

    The Chinese dust cloud probably started in the 1980’s and cannot explain the 1940-970 cooling.

    There are also anecdotal accounts of a major dust cloud in eastern Europe produced by heavy industry.

    All these aerosol clouds are regional and not global phenomena as postulated by the IPCC.

  6. John Bailo

    I think your line of reasoning is absolutely right.

    But I would be more emphatic.

    The “cooling theory” of aerosols is not just an add-on to CO2 “heating theory”. That is, the aerosol theory is a completely new and unverified hypothesis. So, you would need the equivalent amount of research, papers, investigation and so on, to make the case that it can answer why the CO2 theory could not account for the cooling. You can’t just stick it on top of AGW and say, oh, and yes, this would explain the cooling — it’s completely ludicrous!

    Meanwhile, I invite everyone to continue to follow the work of Svensmark, especially the Cloud 9 experiments at CERN. And we should also take note that this years cooling is perfectly in synch with a real minimum of solar activity. (You may remember that Svensmark says that solar activity is like a dimmer switch for cosmic rays…cosmic rays create clouds cooling the earth. Therefore, more solar activity, less cosmic rays, less clouds, more heat. It’s a system involving 3 factors working in the classic rheostat, or transistor design, so I imagine its a bit hard for the linearly inclined typical climatologist to digest).

  7. Douglas Hoyt

    The climate modelers introduced a large upward trend in global aerosols because, without them, their models ran too hot, predicting a global warming of circa 2C in the 20th century, as opposed to the observed 0.6C warming.

    As I have pointed out, there is no evidence that the claimed global trend in aerosols existed. At best there were a few regional aerosol clouds covering less than 1% of the globe.

    The proper solution to their problem would have been to lower the climate sensitivity to 1C or less. In fact. Lindzen has a convincing paper out recently showing the climate sensitivity is about 0.6C for a CO2 doubling.

    The scientific solution to the problem: No large global trend trend in aerosols and low climate sensitivity.

    The political “solution” is: Unsupported claims of large aerosol increases which allows the fiction of the a high climate sensitivity to be maintained, leading to alarming and false predictions of catastropic future warming.

  8. PeterK

    Up at Realclimate, they dismiss Svensmark because – as far as I can make out – he only submitted one set of data. Does anyone understand the issue here?

  9. JamesG

    A perfect summary Douglas. I wonder if a 3rd party review might have fixed it. There are times when you get a weird modeling result and you can’t find the problem so you rationalize it or add a fiddle factor. Only later do you see where the mistake was. Also sometimes throwing money at a group to investigate a problem can fail due to an over-riding need to justify the money and claim more of it.

  10. Blaggarde

    Great article. But I’m entering:

    “…The research that shows that decade-long periods of static/declining temperatures are to be expected against the background of a warming trend (see the Spiked article above) makes no claims that such natural variation could account for the much longer post-war slump…”

    for the gobbledegook awards in the Plain English campaign.

  11. Stefan

    Incidentally, has anyone read “The Way” by Edward Goldsmith? I used to have a copy on my shelf but never got round to reading it.

    Look at his Wikipedia entry and there’s a lot of “anti-human” potential on there (relevant to the other thread–perhaps as founder of The Ecologist is is indeed true that the “real core” of environmentalism is anti-human).

    Funnily enough it ends with mentioning a spat with Monbiot. Apparently Edward can seem a little too far-Right, which maybe has something to do with his nephew Zac becoming a green Conservative, as seen on Newsnight recently (yet another thread).

    Is it just me that’s woken up? Did everyone else here already know this was all connected?

    I really should have got round to reading that book–instead I think I gave it away of Oxfam.

  12. Stefan

    Kinda fascinating to go back and read an issue of The Ecologist from 1970 (they all seem to be available as nice scans on their web site!)

    “In what are, in evolutionary terms, very recent times, its surface or biosphere has been seriously disturbed by two events giving rise to tendencies which, if unchecked, could transform it into a lifeless waste. The first of these events was the agricultural revolution that occurred some 10,000 years ago…”

    Perhaps some would argue that native tribes are humanity’s only “sustainable” form of life on the planet…? (Purple in SD terms).

  13. geoffchambers

    Stefan #11
    No, I don’t think everyone else knew all this was connected. I think we all rely on each other to make connections…
    Just as your reading of back numbers of the Ecologist renders a service to us all. (It’s a crap job, but someone’s got to do it).
    I loved this:
    “its surface or biosphere has been seriously disturbed by two events giving rise to tendencies which, if unchecked, could transform it into a lifeless waste. The first of these events was the agricultural revolution …”
    Too right. Growing things makes things die.
    or to quote the peer-reviewed Ecclesiastes:
    One generation passeth away, and another generation cometh: but the earth abideth for ever. The sun also ariseth, and the sun goeth down, and hasteth to his place where he arose. The wind goeth toward the south, and turneth about unto the north; it whirleth about continually, and the wind returneth again according to his circuits. All the rivers run into the sea; yet the sea is not full: unto the place from whence the rivers come, thither they return again… also when they shall be afraid of that which is high, and fears shall be in the way, and the almond tree shall flourish, and the grasshopper shall be a burden, and desire shall fail: because man goeth to his long home, and the mourners go about the streets..

  14. Alex Cull

    There are some quotes from The Hitchhiker’s Guide to the Galaxy by Douglas Adams, which also seem reasonably apt:

    “In the beginning the Universe was created. This has made a lot of people very angry and has been widely regarded as a bad move.”

    “This planet has – or rather had – a problem, which was this: most of the people on it were unhappy for pretty much of the time… Many were increasingly of the opinion that they’d all made a big mistake in coming down from the trees in the first place. And some said that even the trees had been a bad move, and that no one should ever have left the oceans.”

    On the subject of putting the technological genie back into the bottle and returning to a more basic mode of existence (or preparing for it, chiefly by writing poems and novels about the general theme, as you do), has anyone had a look at Uncivilisation, i.e., Paul Kingsnorth and his Dark Mountain Project?

    Some interesting reading here:

    And here (comments as well):

    And a rather thoughtful essay by Josie Appleton here:–towards-human-species-consciousness

    More about the Appleton essay here, with comments by Paul Kingsnorth:

    Being someone who Paul would probably describe as a spiked! gang-type techno- and futurephiliac myself (the future I’d like to see has humans colonising the solar system and billions living in orbiting space habitats, as per The High Frontier by Gerard K O’Neill) I’m puzzled by the Uncivilisation concept. Even George Monbiot makes sense by comparison. What am I missing here? What is the vision? Or is that the point – there isn’t one?

  15. George Carty

    The Chinese dust cloud probably started in the 1980’s and cannot explain the 1940-970 cooling.

    I was talking about the post-2000 cooling, not the 1940-1970 cooling…


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