Main Ice Age Page | Sci.Env Page

Analysis of Lowell Ponte: The Cooling

For many years I have been tantalised by quotes from the semi-mythical book "the cooling" by Lowell Ponte. Now (thanks to the zShops second-hand booksellers program, a part of amazon) I got hold of a copy, shipped across the atlantic in little more than a week, for only $10.

The book is "popular science": as it says (remarkably) in the preface by Reid Bryson: "...There are very few pages that, as a scientist, I could accept without questions of accuracy, of precision, or of balance..." and any claim to utility it may have would have to come from bringing interesting ideas to the general public (of the time).

In this analysis, I'm interested in whether the book accurately reports the state of science as then known and what issues it chooses to focus on. Its also interesting to see what uses other people put it to, now. Its often cited in the "but 20 years ago people were predicting cooling" type pages.

Lets just prove that, shall I?

The cooling has already killed hundreds of thousands of people in poor nations... If it continues, and no strong measures are taken to deal with it, the cooling will cause world famine, world chaos, and probably world war, and this could all come by the year 2000. Lowell Ponte, The Cooling, 1976 (from

What global warming proponents don't want people to remember is that just 20 years ago, they were predicting that global COOLING would destroy the world. Lowell Ponte wrote The Cooling on the subject in 1976 (which incidentally, can be found in Hodges Library). The theory then said that particulates reflected sunlight into space, thus preventing heat from reaching the earth. Predictions of a new ice age abounded. Then the earth started warming up. Whoops. (from

Book Structure

  1. Foreward (by US Senator Claiborne Pell)
  2. Preface (by Professor Reid A Bryson)
  3. Part I: Forces that change climate (3-76)
    1. Reports of decrease is sunshine / aerosol & dust / ice-albedo feedback
    2. Cooling interrupts predicted warming / "GH" effect & CO2 / CFCs and ozone / Heat pollution / Warming vs Cooling
    3. Some dodgy climatology / Why cooling might be accompanied by warming
    4. Milankovitch-y stuff / Sunspots / Gravity weakening!?! / "Summary"
  4. Part II: The human side of climate (77-176)
  5. part III: Options in a changing climate (177-246)
  6. Appendices: (247-296)
  7. Back-cover quotes from Pell, and Stephen Schneider. Inside quote from Emilliani.
The "science" of the book in contained within part I, which I've read moderately carefully; I've skimmed parts II and III.

Ponte gets some points for noting (p13) that the "greenhouse effect" is misnamed. But that is the high point of his science.

Evidence for Pontes inability to tell sense from nonsense (or at least to check speculative results) is his assertion (p70) that gravity is weakening in the universe, and that this is proved by the moon moving away from the earth at 4 cm/year.

The first chapter starts off with stuff about decreases in sunshine (from few measurements from industrialised areas; I'd guess that was consistent with aerosols) then notes the Rasool and Schneider 1971 science paper (but only in passing. See main page for more on R+S). Ponte asserts that R+W estimate that man's potential to pollute will increase six- to eightfold in the next fifty years. I think this is wrong: R+S actually say it is still difficult to predict the rate at which global background opacity of the atmosphere will increase with increasing particulate injection by human activities. However, it is projected that man's potential to pollute will increase 6 to 8-fold in the next 50 years.... I think they are reporting other peoples estimates to use as feed for their model, not making their own.

Stephen Schneiders quote

The back cover of the book has this from Stephen Schneider:

The dramatic importance of climate changes to the worlds future has been dangerously underestimated by many, often because we have been lulled by modern technology into thinking we have conquered nature. But this well-written book points out in clear language that the climatic threat could be as awesome as any we might face, and that massive world-wide actions to hedge against that threat deserve immeadiate consideration. At a minimum, public awareness of the possibilities must commence, and Lowell Ponte's provocative work is a good place to start.

I'd say this is a regrettable quote. But its not really the ringing endorsement that it is often presented as.

Reid Brysons Preface

Bryson's preface is rather odd, because it indirectly contradicts much of what is in the "science" sections of the book. Lets read it, shall we:

The Cooling will be controversial, because among scientists, most of the matters it deals with are hotly debated. There is no agreement on whether the earth is cooling. There is not unanimous agreement on whether is has cooled, or one hemisphere has cooled and the other warmed. One would think that there might be consensus about what data there is - but there is not. There is no agreement on the causes of climatic change, or even why it should not change amongst those who so maintain. There is certainly no agreement about what the climate will do in the next century, though there is a majority opinion that it will change, more or less, one way or the other. Of that majority, a majority believe that the longer trend will be downward. Nevertheless, it is an important question, as this book points out, and it is time for some of the questions to be settled. Lowell Ponte has summarized the data and theories very well, and has reasonably concluded that a rapid change in Earths climate is possible, perhaps even likely, within the next few decades, and that this would have serious consequences for mankind.

OK, lets stop there for a moment and compare this to what Ponte has to say:

Opening words of chapter 1: "Our planets climate has been cooling for the past three decades. Most experts agree on this, for it has been carefully measured by scattered monitoring stations throughout the world. Climate in the southern half of our planet has been warming rapidly, according to the few measurements available. But in the hlaf of our world north of the equator, where most human beings live, the annual mean atmospheric temperature has plunged by 0.7 oC, more than enough to offset the southern warming and to lower the average temperature of the whole planet by 0.5 oC."

Some disparity with Bryson, I hope you can agree. Looking at Pontes words further, note how, despite asserting that there are few southern measurements, he is nonetheless happy to assert that the globe as a whole is cooling. Where he gets the 0.7 oC cooling is a mystery: he cites no source; the graph reproduced in appendix 1 of the book shows a cooling of possibly as much as 0.4 oC. [Somewhat later, p45, the 0.5 global warming is qualified as "according to available measurements".]

This failure to acknowledge uncertainty is not something trivial, to be passed over rapidly. It is crucial. Brysons central point, that people are not really sure whats going on, was a good one to make at the time and thoroughly justified by hindsight.

OK, on with the preface:

"There is surprisingly little argument among those who have actually studied climates over multi-millenial time scales that we will be in an Ice Age 10,000 years from now. There is, however, less agreement about how soon and how rapidly the transition from the present interglacial will take place...".

I quote that to point out that (AFAIK) it was indeed typical of the views of the time (at least amongst those that extrapolated the past into the future); that it is probably not accepted widely now [TS Ledley, 1995, ???]; and to wonder if "among those who have actually studied climates..." is a dig at some other group.

Skipping over, we come to: "...There are very few pages that, as a scientist, I could accept without questions of accuracy, of precision, or of balance... but he then goes on to say that the book is worth reading for its presentation of the arguments. I'm somewhat surprised the publishers let him keep that bit in, its not really very complementary.

Pontes Misuse of the 1975 NAS report

Ponte says (p4) "Are we at the dawn of a new Ice Age? In 1975 the US National Academy of Sciences issued a report saying that if the present cooling trend continues, there is a "finite" chance an Ice Age could begin "within 100 years". How much chance? The NAS panel...set the odds of this happening at no better than one in 10,000. The number was not random [Oh good, thats a relief - WMC]. As their report noted, Earths climate in the past has tended to change in fairly regular cycles, and if the past patterns continue we should now be entering a 10,000 year period of cooling climate.

The NAS report was shocking...".

The NAS report was not shocking. Anyone reading it would be more likely to describe it as "soporific". See here for some notes I made from that report. But to quote some of it here:

  1. "The climates of the earth have always been changing, and they will doubtless continue to do so in the future. How large these future changes will be, and where and how rapidly they will occur, we do not know" (from the intro; note how how this resembles Brysons initial words)
  2. The recommendations were: Establish National climatic research program; Establish Climatic data analysis program, and new facilities, and studies of impact of climate on man; Develope Climatic index monitoring program; Establish Climatic modelling and applications program, and exploration of possible future climates using coupled GCMs; Adoption and development of International climatic research program; Development of International Palaeoclimatic data network. There was no recommendation for action.


It occupies pages 296-269=27, so there are 28 pages of bibliography.

I thought it would be interesting to look in Ponte's book to see which statements are backed up by which references. Its easy, after all, to stuff a bibliography full of references - but what matters is which statements are backed up by respectable scientifc references, and which are backed up by fluff from the newspapers. But (yet another flaw in Ponte's book), you can't do this, because the bibliography is just a "selected bibliography", *not* a directed source of references for particular statements. So its impossible to tell what statement a given reference is intended to support, or indeed which statements are supported by references, and which are fluff.

Anyway: the bibliography is largely non-scientific. Page 269 (the first page):

Science (ie, as in the prestigous mag): iii
esquire: i
science news: iiii
los angeles times: iiiii
fortune: ii
readers digest: i
n y times: ii
playboy: i
"african genesis": i
"the ends of the earth (asimov)": i
smithsonian: i
unesco courier: ii
time: i
"readings in man, the env and ecology": i
sci am: ii
"lao tzu": i
"western amn and env ethics": i
"harvest of the sea": i
and I've no reason to believe that untypical.

Lazy people have complained that one needs to index the whole bibliography to be sure of the sci/non-sci content. Are you one of these people? Then please do the said indexing and send it to me.

Misc bits: peoples use of LP's misquotes of NAS 76

In January 1975 the National Academy of Sciences issued a report entitled Understanding Climatic Change: A Program for Action. There is, it said "a finite possibility that a serious worldwide cooling could befall the earth within the next hundred years...

Misc - post by mt. - by jbs

Other text

A search of the citation indices reveals that the only other publications by Ponte, L were in Readers Digest, the most recent in 1991. Read something about him here. John McCarthy has a quote that he asserts comes from the book.

Here is some text I was mailed:

For nearly three years, Lowell worked as a futurist in the high tech think tank International Research &
Technology; Inc., as first assistant to Dr. William Van Leave (who later served as chief weapons advisor to
America's SALT I delegation and as chief strategic advisor to presidential candidate Ronald Reagan in

Lowell wrote a prophetic 1976 book about global climate change, The Cooling (Prentice-Hall; forward
by U.S. Senator Claiborne Pell, preface by Univ. of Wisconsin Climatologist Reaid A Bryson), which was
widely reviewed and went through five printings.

W. M. Connolley