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World Climate Conference 1979

WMO proceedings of the World Climate Conference: a conference of experts on climate and mankind. Geneva, 12-32 February 1979. WMO - No. 537. ISBN 92-63-10537-5.

Notes by W. M. Connolley. Direct quotes from the conference report are in quotes, often followed by page numbers. My interpolations thus: [text... WMC].

This is an interesting document. As usual, it was brought to my attention by a skeptic, who misrepresented it. This is common, but why? My best guess is false-memory. In weather, vol 58, august 2003, p 311, M R Morgan says: "...recall the concern that we conveyed to the public, particularly during the 1970's, when after over 30 years of cooling we were convinced that a return to Little Ice Age conditions was imminent (Hare, 1979)" and the Hare ref is to the Hare article in this volume. What Hare says is slightly complex, but doesn't support Morgan: Hare offers no predictions of future climate. However the conference declaration says, in part: "Climate will continue to vary and to change due to natural causes. The slow cooling trend in parts of the northern hemisphere during the last few decades is similar to others of natural origin in the past, and thus whether it will continue or not is unknown". (See here).


  1. Foreword (vii-ix)
  2. Preface (xi-xii)
  3. Keynote address (1-14)
  4. Overview Papers (15-693)
  5. Declaration and supporting documents (709-758)
  6. Appendices (759-791)


From the foreword: by D. A. Davies, Secretary General. Notes that WMO decided on the conference in 1977, with the purposes:
  1. Review knowledge of climatic change and variability, due both to natural and anthropogenic causes
  2. Assess possible future changes and variability and implications for human activities
"The conference noted that there was an additional issue of special importance that pervades all the above-mentioned components: the problem of possible human influence on climate."

"This publication may safely be considered as the most profound and comprehensive review of climate in relation to mankind yet published."


From the preface: by Robert M. White.

"The declaration of the conference appearing in these proceedings was prepared and unanimously adopted during the second week of the conference."

Keynote address

From the keynote address: by Robert M. White.

"The timing of our meeting is a response to several concerns. The first is the worldwide reaction to the climatic events which have so disrupted human society over the past decade [What events? See below. WMC]. The second arises from a growing apprehension that not only is humanity vulnerable to variations in climate, but climate is vulnerable to the acts of humanity. The third is a perception of a broader climatic vulnerability stemming from world population growth, increased world demand for food, energy and other resources..."

"...climatic events of the past decade... the Sahel, succumbed to a five-year drought... drought in the Soviet Union and the occurence of El Nino off Peru. In 1974 poor monsoons reduced food production in India. In 1975, cold waves in Brazil badly damaged coffee crops. In 1976, drought in Europe... In the U.S., the recent cold winters forced many industries and school to close".

"In recent years we have come to appreciate that the activities of humanity can and do affect climate. We now change the radiative processes of the atmosphere... The potential consequences of increasing atmospheric CO2 resulting from fossil fuel combustion are already a major concern...". "The implications of further projected increases [in CO2] are uncertain, but the weight of scientific predicts a significant global surface temperature increase."

"The executive committee of the WMO has specifically asked this conference to recommend whether a conference at the ministerial level should be convened to take necessary international actions." In fact, the declaration of the conference does not explicitly call for such a conference, though the conference declaration is called "An appeal to nations". It looks to me as though they ducked the issue (or maybe they just thought it was a dumb idea best ignored), in that they have neither explicitly accepted or rejected this idea.

Overview Papers

F. Kenneth Hare, U Toronto, Canada "Climatic variation and variability: empirical evidence from meteorological and other sources"

"...drought, floods, extreme cold and severe storms have impressed themselves on public memory. [p 51]"

[Fig 3, showing slow warming for the past 2000 Myr. WMC] "... we live in an abnormal phase of a planetary climate that in most epochs permitted a largely ice-free surface [no refs. WMC]... Man's entire evolution took place during this cool phase of Earth history. The cooling began in mid Tertiary times (about 50 Myr back) culminating in the series of glacial and interglacial epochs of the Quaternary times... [p 57]"

"Section 6.2 trend of mean temperatures since 1880. Fig 8 shows... 1938 the warmest year. They have since fallen by about 0.4 oC. At the end there is a suggestion that the fall ceased in about 1964, and may even have reversed.

Figure 9 challenges the view that the fall of temperature has ceased... the weight of evidence clearly favours cooling to the present date... The striking point, however, is that interannual variability of world temperatures is much larger than the trend... it is difficult to detect a genuine trend...

It is questionable, moreover, whether the trend is truly global. Calculated variations in the 5-year mean air temperature over the southern hemisphere chiefly with respect to land areas show that temperatures generally rose between 1943 and 1975. Since the 1960-64 period this rise has been strong... the scattered SH data fail to support a hypothesis of continued global cooling since 1938. [p 65]"

"The small hemispheric or global changes are actually insignificant by comparison with the large spatial anomalies that have been demonstrated. During this century there have been prolonged and persistent spatial anomalies much larger in magnitude than the hemispheric trends discussed above. [p 66]"

"Nevertheless the trends will ultimately affect the human economy, if they continue, or if they reverse and then endure. A cooling of 0.2 oC/decade would reduce world temperature by 1 oC if it continued for 50 years (i.e. to about 2027). This would be quite enough to have an impact on NH agriculture. It might affect warm temperature agriculture beneficially, since many crops are grown above their optimum temperatures. There might also be associated changes of precipitation. OTOH, if the trend reverses because of CO2 heating (see for example overview papers by Flohn, Mason, Munn and Machta, and Bolin), it will also create economic impacts. We conclude that temperature variability has much greater present impact that that due to long-term trends, but that such trends must be watched with the utmost care. [p 68]"

"Duing the 1970s drought has been a major contributor to the sudden impact of climate on the human economy... [p 74]".

Interesting discussion of El Nino (p 79) showing how little was known about it then.

"7. Conclusion. No simple conclusion emerges from this review... A first impression that one gains is of underlying stability... Overwhelmingly, however, the main climatic stress of the past decade has been due to short-term climatic anomalies of precipitation... (c) the recent trend of atmospheric and sea surface temperatures has been downward, at a rate of 0.1 to 0.2 oC per decade, at least in the NH. It may be offset by heating due to atmospheric contaminants such as added CO2, or chemical synthetics. The general trend of planetary temperatures has been downward for 50 million years [this statement is weakly supported by p 57]. The present decline, however, is probably part of a shorter-term fluctuation typical of records of the more recent past [p 79-81]".

B. J. Mason, UKMO Some results of climate experiments with numerical models

Describes and evaluates UKMO and GFDL GCM's.

"Section 5.2 Climatic effects of increasing CO2. ...Since it strongly absorbs the long-wave radiation emitted by the Earth's surface, higher concentrations of CO2 should produce higher temperatures in the troposphere by the so-called greenhouse effect but, because the CO2 in the stratosphere emits more infrared radiation to space than it absorbs, there should be a corresponding cooling of the stratosphere.

Early estimates of the warming due to increased CO2 were exaggereated because they were based on simple, globally averaged, one dimensional models... no allowance being made for the redistribution of the radiative heating by atmospheric motions.

More sophisticated one-dimensional models, making some allowance for the vertical transport of heat by convection and for the radiative properties of water vapour anc clouds, provide estimates for the globally averaged increase of surface temperature Ts, due to doubling of the CO2 concentration to 600 ppm, ranging from 1.0 to 3.0 deg K... [p 230]"

Notes deficiencies of 1-d models. Notes a very early expt with limited area type GCM (Manabe and Wetherald, 1975) and need for better models. Notes on problems of predicting climate.

Reports ("additional note") on "recent" experiments by the UKMO 11 level global (atmos-only) model. With fixed SSTs [Note: this was all that was available then: nowadays coupled ocean-atmosphere GCM's are used. WMC], 2*CO2 increases global land T by 0.4 oC; adding 2 oC to all SSTs raises all T's by 2.7 oC. Notes that the first "probably minimises" T rises; the second "probably overestimates" them. Notes need for coupled ocean/atmos models.

H. Flohn, Met Inst, U Bonn, FRG A scenario of possible future climates - natural and man-made

H. Flohn.

"Section 3.2 Initiation of a new ice age? ...At any rate, the transition from the present climate towards a large-scale glaciation - which should hardly be expected before the radiation minimum 7000-13000 years in the future - needs much more than 100 years before the ice expands beyond Baffin island and the adjacent areas of the Canadian Archipelago. This is also suggested by the fact that the cooling of the Little Ice Age, extending over 300 years, was not sufficient to expand the Baffin ice sheet much beyond the high plateaux. [p 261]"

"Thus in a scenario of probable climatic evolution during the 21st century it is unnecessary to consider the evolution of a new ice-age. [p 262]"

"Section 4 Conclusions ...In many discussions the possible occurence of a sudden cooling due to natural causes has been neglected. The probability of heavy volcanic eruptions, perhaps a cluster of them, with the intensity of Krakatoa (1883) or even Tambora (1815) can never be excluded. Indeed the very recent increase of seismic activity seems to indicate an active phase of tectonic motion of the large plates of the Earth's crust... A cluster of heavy explosions (similar to periods around 1690 or 1830) could suddenly initiate a marked period of cooling, possibly similar to the Little Ice Age. Assuming an irregular behaviour of fluctuations on the time scale of around a century with successive peaks occurring at random, the risk of such an evolution during the next 100 years can be estimated somewhere between 10 and 20 per cent. With increasing global warming, this risk may diminish gradually but never disappear."

"In contrast... the probability of a man-induced future global warming is much greater and increases with time. Soon after the turn of the century a level may possibly be reached that is exceeds all warm periods of the last 1000-2000 years;... [p 262]"

"This is the more true for an eventual transition to an ice-free Arctic Ocean. If an increase of the virtual CO2 level by a factor of 3 or 4 - assumed to be equivalent to an increase of the real CO2 content towards 750-900 pppm - cannot be impeded, the probability of such a dramatic event rises rapidly. ... The occurence of such a climatic evolution, leading - after a series of catastrophic years of extremes - to such a nearly unimaginable climate... must be avoided even at very high costs. [p 263]"

Declaration ("An appeal to nations") and supporting documents

"... it is now necessary for the nations of the world:
  1. to take full advantage of man's present knowledge of climate;
  2. to take steps to improve significantly that knowledge;
  3. to foresee and to prevent potential man-made changes in climate that might be adverse to the well-being of humanity.
" Hmm. Thats a bit dull, isn't it?

From a section headed "Climate and the future" (thats more like it!):

"Climate will continue to vary and to change due to natural causes. The slow cooling trend in parts of the northern hemisphere during the last few decades is similar to others of natural origin in the past, and thus whether it will continue or not is unknown".

Well, that seems clear enough: there is no prediction given about the future of the cooling trend. On the other hand, of possible warming from CO2 rises they say:

"...increased the amount of CO2 in the atmosphere by about 15% during the last century and it is at present increasing by about 0.4% per year. It is likely that an increase will continue in the future... it appears plausible that an increased amount of CO2 in the atmosphere can contribute to a gradual warming of the lower atmosphere, especially at high latitudes".

This isn't a prediction of warming such as you would find in the 2001 IPCC TAR, its a much weaker statement of plausiblity appropriate to the level of knowledge of those times.

From the "Conclusions and recommendations": "

  1. The world climate programme proposed by the WMO deserves the strongest support of all nations
  2. The WCP... requires leadership and co-ordination among international bodies and close collaboration among nations".
  3. There is an immeadiate need for nations to utilize existing knowledge of climate and climatic variation in the planning for social and economic development".

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