Repeat After Me: Carbon Dioxide Is Good for Us, by Ian Plimer

The opinion essay that begins in the third paragraph below was published on August 7, 2018 in The Australian, the most widely circulated daily newspaper in Australia. Ian Plimer is an Australian geologist, professor and former Head of the School of Earth Sciences, University of Melbourne. He is the author of several books including Heaven + Earth: Global Warming: The Missing Science (2009).

The essay addresses the conventional narrative that human activity is causing potentially dangerous global warming. In the current politicized debate about the Earth’s climate, an internet search will turn up detailed commentary criticizing the essay and impugning the author’s motives. Dr. Plimer’s credentials and his analysis speak to the validity of his argument. He has had a long and distinguished academic career. For nearly twenty years Professor Plimer has devoted much of his thought to the hypothesis that human activities are causing a change in climate that will lead to dangerous global warming.

Repeat After Me: Carbon Dioxide Is Good for Us, by Ian Plimer

Climate policy is underpinned by two fallacies. The first is that human emissions of carbon dioxide drive global warming. The second is that future climate can be predicted from computer models.

It has yet to be shown that human emissions of carbon dioxide drive climate change. More than 100 climate models over the past 30 years did not predict what actually happened because it was assumed carbon dioxide had the pivotal role in driving climate change and that the effects of clouds, back-radiation and the sun were trivial.

Climate projections also assume that planet Earth is not dynamic and that a temporary terrestrial vertebrate on an evolving planet can change major planetary and extraterrestrial systems

Unless the past is understood, climate projections can be only highly speculative. Even in our own lifetimes, there is no relationship between temperature and carbon dioxide emissions by ­humans, yet there is a very close relationship between solar activity and temperature.

Since the beginning of time, water vapour has been the main greenhouse gas and carbon dioxide has had a minuscule effect on global climate.

Carbon dioxide is a trace gas in the atmosphere. We are expected to believe that emission of traces of a trace gas into the atmosphere is a major planetary driving force. If the atmosphere comprised 85,000 molecules, the total carbon dioxide emissions added annually would be 33 molecules, of which only one molecule would be from human emissions and the other 32 from natural emissions. Do we really believe that one bellowing fan in a crowd of 85,000 at the MCG can completely change the course of a game? 1

For the past 4567 million years, the sun and the Earth’s orbit have driven climate change cycles. In the past, the atmospheric carbon dioxide content has been orders of magnitude higher than now, yet there were ice ages.

We currently live in an interglacial during an ice age with alternating cycles of glaciations and interglacials. The current interglacial reached a peak about 5000 years ago. Since then, the planet has been cooling on a millennial scale and no amount of hot air, agreements, taxes, environmental wailing or legislation can change the fact that the Earth’s orbit is slowly taking us farther from the sun.

Just 1.25 per cent of the carbon dioxide in the atmosphere-ocean system has been released by ­humans in the past 250 years. The ­atmospheric residency time of carbon dioxide is five years and it is quickly sequestered into plants, marine life, oceans and sediments. 2

If human emissions of carbon dioxide drive global warming, why have there been slight warmings and coolings since the Industrial Revolution? Why is it that human emissions of carbon dioxide drive global warming yet natural emissions do not?

Carbon dioxide is plant food. Horticulturalists pump warm carbon dioxide into glasshouses to stimulate growth. Over the past 30 years, planet Earth has greened due to a slight increase in atmospheric carbon dioxide.

Without carbon dioxide, there would be no complex life on earth. It is neither pollution nor a poison, and in the past the atmospheric carbon dioxide content has varied enormously.

When the atmospheric carbon dioxide content was low, plants struggled. When it was high, there was an expansion and increasing diversity of vegetation.

In addition, when it was warm, life expanded, whereas when it was cold, life contracted. Over historical times, when it was cold there was human depopulation. When it was warm, economies thrived.

Biological, geological and planetary systems are extremely robust. Our evolving dynamic planet has survived sea level changes of hundreds of metres, super volcanoes filling the atmosphere with dust, asteroid impacts, mass extinctions, ice ages and global warming. For most of time, Earth has been a warm, wet volcanic planet with no polar ice.

Australia has uranium, coal and gas for generations. Fracking for tight gas and oil could further extend energy resources. We are the envy of the world. Australia once had cheap, reliable electricity and the states competed to provide cheap, long-term, reliable energy to attract industry.

Now the states rely on the weather and compete to reach the bottom. South Australia is winning: it has the most unreliable grid in the world outside Africa and the most expensive electricity. When South Australians buy electricity at $14,200/MWh, they are paying the equivalent of $400 a litre for petrol.

As soon as the word emissions entered the language and became part of a religious ideology, electricity prices skyrocketed, electricity supply became more unreliable, subsidies for wind and solar energy went through the roof and employers and consumers had massive cost increases. Never mind that the emissions of carbon dioxide to make and maintain a wind or solar industrial complex are far greater than they will ever save.

The Paris accord is non-binding. This is recognised by the major carbon dioxide emitters such as China, India and the US, which don’t comply. No EU state has met its target. Why should Australia be the only country out of step and aim for an impossible, bankrupting reduction of 26 per cent or more of our 2005 carbon dioxide emissions?

Pragmatism and principled inaction is the correct policy to ­address the non-problem of human-induced climate change promoted by the Paris accord. But do our politicians have the courage to thoughtfully do nothing?

We are in an electricity crisis because we are trying to decrease human emissions of carbon dioxide and have tied climate policy and electricity generation costs to emissions. A reality check is needed. Even if human-induced global warming could be shown, a reduction in Australian emissions, comprising 1.3 per cent of global annual emissions, is dwarfed by annual increases of 2 per cent globally and 4 per cent by China.

Australia’s symbolic suicidal climate policy just makes everybody poorer.

We face further turnover of prime ministers and governments until the costs and reliability of electricity are addressed and until the fundamentalist religious mantra that emissions drive global warming is rejected.

Politicians need to realise that the electorate wants cheap electricity and a reduction of emissions concurrent with subsidies for unreliable weather-dependent electricity can neither reduce costs nor increase reliability.

Meanwhile, employment-generating businesses will close, household costs will become impossibly high, international competitiveness will fall and governments will change.

Emissions must be banned. From the language. Not from coal-fired power stations that have provided cheap, reliable electricity for generations. It is only then that we will have stable government and cheap reliable electricity again.

Emeritus professor Ian Plimer’s latest book, Climate Delusion and the Great Electricity Rip-Off, is published by Connor Court.




  1. MCG is the accronym for Melbourne Cricket Grounds, a large sports stadium in Melbourne, Australia
  2. For the source of this statement see “Isotopic mass balance calculation (Segalstad 1992, and later) finds an air CO2 lifetime (halflife) ~5 years, like many other studies with other methods. ~18% of air CO2 is exchanged annually in nature, about 20 times more than added anthropogenically.” Quoted from “Web info about CO2 and the asserted “Greenhouse Effect” Doom” by Tom V. Segalstad, Assoc. Professor Emeritus of Geochemistry, University of Oslo, Norway, at 
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10 Responses to Repeat After Me: Carbon Dioxide Is Good for Us, by Ian Plimer

  1. David L. Wood, M.D. says:

    Besides the Mueller Investigation, the political intent to “carbon tax” and propound the idea of man’s influence on global climate is a far larger hoax and destructive conception. CO2 is only 3.6% of the atmospheric “greenhouse” gas, while water vapor is 97%. Mann’s contribution is a small percent of that. For us less-than-scientific individuals, to look at the huge amount of atmosphere over the oceans, the uninhabited land masses and the poles, to even think that all of man’s industrial output and engine emissions could put enough carbon into that atmosphere to alter it is preposterous. Perhaps locally as in LA, Beijing, Pittsburg, etc. the air contamination is worth cleaning up, but that’s it. The vast majority of CO2 in the air comes from the oceans and the deep volcanoes there. I have some pretty clear studies to detail all this, should you desire to read it. However, for those persons believing otherwise, absolute closed-mindedness is the rule.

    • fgmarks says:

      David: You are right. However, to me it is incontestable that in some important ways human activity is harming the environment in a way that is or will be become harmful to human beings. Testing atomic and hydrogen bombs in the atmosphere was one such activity. Disposal of human and industrial waste in rivers and the oceans is another. The amount of plastic in the oceans could in time amount in mass to more than the mass of all the fish in the sea.

      Fortunately, the best remedy for human pollution and despoliation of the environment is knowledge and free enterprise, that together allow accumulation of wealth in a society. It is the wealthy societies on earth that have done the most to mitigate or remediate the harmful effects of human activity. Wealth and the ability to protect the environment come from the productivity allowed by free enterprise.

      Most of the political solutions to degradation of the environment are avowedly or unintentionally restrictive on free enterprise.

  2. Ron Zamarin says:

    In my opinion, here is another excellent, sensible, well written, article written by an extremely qualified individual which will be probably be ignored or worse by the “Green” group in their misguided religious fervor to gain perfection while bankrupting gullible nations. Thanks again for including me in your fascinating and highly informative emails. Hope you are enjoying your semi-retirement in good health and happiness.

    • fgmarks says:

      Ron: Yes, I am enjoying semi-retirement, living in Humboldt County where the trees are tall, automobile traffic is slight, and the climate is usually cool and comfortable. Ian Plimer is a big annoyance to those for whom AGW has become a near religious belief.

  3. Richard Boren says:

    The claims made by Ian Plimer in his Op-Ed are what virtually every human would like to hear: humans aren’t causing harmful climate change. The exception would be those who benefit in some way from the belief that they are.

    Plimer makes it all seem so simple–black and white, really. Models don’t work, and the amount of CO2 in the atmosphere is too little to do any harm. Rather, it is a net benefit. I’ve heard these things from credible sources for about 40 years, and have believed that they are probably true. I’ve heard it said that the anthropogenic global warming (AGW) hypothesis has been “discredited” and I’ve read papers and seen graphs that purport to show this.

    So why doesn’t AGW go away? Are the (probably) thousands of scientists and technicians who support it stupid? Or are they intellectually dishonest? Have they been, in effect, bribed by means of employment and research grants to say anything that will ensure a continuation of their income?

    Plimer’s article provoked negative responses from scientists, some of which can be seen here .

    In the spirit of intellectual honesty I encourage everyone who wants to believe that Plimer is right to go to the above link and see the very specific criticisms of virtually everything he said. Are these people all stupid or corrupt? As a layman without the ability to analyze their claims, I cannot say. But this is an example of why I am no longer as convinced that they must be because people I respect say so.

    • fgmarks says:

      Richard: You are right that the AGW hypothesis is endorsed and embraced by many people who are trained and employed in science. That does not make them right and Plimer wrong. Henry
      David Thoreau observed that any individual more right than others constitutes a majority of one. Thomas Jefferson said that each individual must make up his own mind about important questions. I agree with that. Personally, I have purchased and read parts or all of more than 25 books on climate and geology. Some of the authors embrace the AGW hypothesis; others do not. I have read material regarding climate on a number of websites and in a number of articles published online. I have delved into websites devoted to falsifying and debunking scientists who dissent from the AGW hypothesis. Authors who are scientists that I respect embrace or at least do not dismiss the AGW hypothesis.

      In the big picture of the entire 4.57 billion years of the geologic history of the earth, phenomena that Plimer points out are not in dispute by anyone. For example, for much of geologic history, covering hundreds of millions of years, earth was warmer than now and did not have polar ice caps; sea level has been more than 100 meters higher and lower than at present at times when no humans were in existence; there is no striking correlation between atmospheric concentration of CO 2 and temperature over long and short periods of time in both geologic history and modern times; all greenhouse gases including water vapor are trace elements in the atmosphere; CO 2 is a trace gas within the atmospheric gases of which water vapor is by far the largest element; CO 2 concentration at present levels is trivial compared to the overall composition of the atmosphere.

      The AGW hypothesis is a manifestation of the concept that correlation shows causation; however, in logic and science that is an erroneous concept; the test of any hypothesis about nature is observation; when observation shows that a hypothesis has not correctly predicted what actually occurs, the hypothesis is falsified; specifically the computer models on which AGW is based have all failed to match what actually occurred.

      On specific points that Plimer makes where others disagree, this is not unusual in science. There have often been disagreements about what data shows. Some AGW adherents in the scientific community say that once a CO 2 molecule enters the atmosphere, it resides there for a hundred or more years. Plimer says it resides in the atmosphere for about five years. Plimer is not alone in saying that. On every point in which Plimer’s assertions are disputed one can find support for what Plimer says.

      More than 100 sub-specialties in the physical sciences have some relation to climate. No one scientist is expert in more than one or two such sub-specialties. Therefore, there are no experts who know everything worth knowing about climate.

      Atmospheric scientist Richard Lindzen has observed that climate is the product of the interaction of two very large and tumultuous systems, the oceans and the atmosphere, and the relation of the atmosphere to the irregular surface of land. I would add that the earth itself is tumultuous as shown by the composition of the planet, with its molten iron core, a semi-molten mantle that comprises 80% of the volume of Earth, and a thin crust about 100 miles deep at most that is also tumultuous as shown by the recently discovered knowledge of plate tectonics.

      With all these influences on climate, the AGW hypothesis, focusing just on a trace atmospheric gas seems to me to be a gross over-simplification of what is going on in the climate.

      Consider the ice ages for example. Climate science has a reasonable seeming explanation for warming and cooling within the current Pleistocene ice age that began 2.6 million years ago and is ongoing. That is the Milankovitch astronomical hypothesis. Its focus is on warming and cooling over cycles of insolation ranging from 11,000 years to 100,000 years. By its own terms the Milankovitch hypothesis cannot explain the four great ice ages of the past that each lasted tens of millions of years.

      The Milankovitch astronomical hypothesis does not explain the Cretaceous period of Earth’s geologic history. During the Cretaceous period that lasted tens of millions of years no polar ice caps existed. Climate was so warm and the sea level so high that most of the North American mid-continent was inundated by the seas.

      Human science is the search for better explanations. So far there have been no explanations for the essential causes of the hundreds of millions of years when Earth experienced alternating ice ages and warm periods when Earth was ice-free. Geological science has established that those conditions existed. It has not explained why.

      If science cannot yet explain the causes that drove the enormous variations in climate over two thousand million years in Earth’s history, it is questionable for proponents of the AGW hypothesis to rule out natural causes for the 0.85 degree Celsius increase in Earth’s average surface temperature over the past 140 years.

      • The reason I provided a link to some of Plimer’s critics is to show that they appear to be credible people, at least to the extent that Plimer appears credible. And to me, their criticisms are at least as plausible as Plimer’s claims. For example, the quote below is from that link (which , in my experience, few or no readers of this will inspect), and it goes to your opinion that focusing on a trace gas (CO2) seems to be an oversimplification. Here’s the quote:

        “Do we really believe that one player in a stadium with an audience of 85,000 can make a difference?

        Naturally also small concentration can matter. Many substances are, for example, poisonous at much smaller concentrations.

        What matters is the amount of CO2. That there are also inert molecules in the atmosphere does not change the radiative influence of CO2.

        It is pretty amazing that Plimer states in this same article that ‘Over the past 30 years, planet Earth has greened due to a slight increase in atmospheric carbon dioxide.’ Suddenly it is no problem that CO2 is a trace gas.”

        When scientists can have such diametrically opposed opinions we laymen are stuck. In principle, we need Plimer’s answer to this, and then the critic’s answer to that answer, and so on. We would probably not see such an exchange should it occur.

        Both sides of the AGW question imply that the other side is corrupt or stupid. Meanwhile the politicians, almost all of them non-scientists, and always in need of votes and more power, will take any position that generates more of each.

        • fgmarks says:

          Richard: In 2009 Ian Plimer published Heaven + Earth: Global Warming—The Missing Science. It is the most comprehensive treatment of the subject that I have seen. There are nearly 500 pages and over 2,200 notes provided to authenticate statements in the book.

          In my opinion one cannot read even two or three pages in the book without being impressed by the care and thoughtfulness of the presentation of evidence about the climate of Earth. The book is evidence-based science.

          To me, much of the writing by those who embrace AGW, including comments by scientists who endorse the concept, is hypothesis and speculation offered as evidence.

          Here is an example. A few years ago it was been discovered that evidence of past climate found in ice cores shows that warming of the atmosphere precedes a rise in atmospheric CO 2 concentration with a lag of hundreds of years.

          That means CO 2 cannot be causing warming. It is the other way around.

          AGW advocates responded by claiming that nevertheless increasing CO 2 concentration was warming the ocean, causing more evaporation and thus more water vapor, and it was the increased water vapor that caused global warming.

          This comment begs the question. It presents as proof that which it has not proven. It has not been proven that CO 2 causes a rise in the temperature of the surface of the ocean. It is also incompatible with the way water vapor acts. The global average atmospheric humidity is about 70%. When water vapor increase causes humidity to go to 100% the result is precipitation that reduces humidity. That is it reduces the amount of water vapor in the atmosphere. Precipitation is a negative feedback that stabilizes temperature rather than forcing it higher.

          I am not asking anyone to judge who is right between Ian Plimer and his critics.

          That he has received fierce criticism is due to the politicization of the global warming issue. It has been political since its inception in the first publication of the United Nations Intergovernmental Panel on Climate Change (IPCC).

          In 2003 author Michael Crichton made two talks, one at Cal Tech and one at the Commonwealth Club of San Francisco.

          The text of these talks is available online at the URL citations below. The Cal Tech talk is entitled “Aliens Cause Global Warming,” January 17, 2003, published at

          A principal premise of this talk is that the use of computer models to project future global warming is not science but rather is a means to substantiate a claim that has been made that has not been substantiated by evidence. There is no data about and can be no data about what will be happening in the climate in the future, just conjecture and supposition. However, the computer projections are being treated as data. They are not data. Data is something that has been observed.

          The principal premise of the Commonwealth Talk is that “the greatest challenge facing mankind is the challenge of distinguishing reality from fantasy, truth from propaganda.” Michael Crichton, Remarks to the Commonwealth Club, San Francisco, September 15, 2003

          Crichton concluded his remarks in San Francisco by stating that “. . . science offers us the only way out of politics. And if we allow science to become politicized, then we are lost. We will enter the Internet version of the dark ages, an era of shifting fears and wild prejudices, transmitted to people who don’t know any better. That’s not a good future for the human race. That’s our past.”

  4. Kevin Maldonado says:

    The key phrase to me is “fundamentalist religious mantra.” There are too many similarities of climate change (global cooling, global warming or whatever they will call it next…) activists and religious zealots to deny their common intellectual links. This is the new confluence of church and State for the benefit of the connected elites at the determent of the average producers.

    • fgmarks says:

      Kevin: To borrow an observation of a professor of geology, Marcia Bjornerud, in another context, “the fierceness of the debate . . . suggests that there are larger philosophical and political agendas . . .” involved.

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