The Productive Way to Address Global Warming

Most of the discussion of global warming is about the wrong questions.  The important debate is about the level of risk, the consequences of inaction and the cost of action.

The debate about scientific uncertainty is secondary, and exploited as a distraction.  So as to minimise the continuing spurious discussions here and elsewhere, I’ll set it out as I see it.


There is always uncertainty in science.  There is uncertainty in the accuracy of measurements, in the completeness of measurements and in the adequacy of our understanding.  For a system as complex as the climate system there will always be uncertainty.  Nevertheless climate science is a lot stronger than is claimed by sceptics.  The main conclusions are supported by multiple independent lines of evidence, so nit-picking one line like “models” does not invalidate it.

Uncertainty cuts both ways

It’s true that global warming might not turn out as bad as we thought.  It’s also true that it might turn out worse than we thought.  In significant ways it is turning out worse than projections from 5 or 10 years ago.


Given the uncertainty combined with the indications of human-caused warming, we need to estimate risks.

• What is the risk that global warming will continue?

• What is the risk that we are causing global warming?

• What is the risk that global warming will have bad or catastrophic consequences?

How do we evaluate the risks?

These risks are not quantifiable.  The best we can hope for is to make well-informed judgements.

Who is best-place to make these judgements?

The judgements obviously require a good grasp of the evidence and a good grasp of our current understanding of how the climate system works.  The people who know these things best are climate scientists.

Who else might make such judgements?  Certainly not politicians, attack-dog journalists and shock jocks, who don’t have the beginning of an understanding of the subject.  Certainly not those whose vested interest is to deny any human-caused global warming.  If you would trust any of them ahead of the scientists who spend their lives working to understand the climate system, then you subscribe to a highly implausible conspiracy theory and ignore a very obvious conspiracy (to spread confusion), and I have nothing more to say to you.

Have such judgements been made?

Yes, and they have been stated clearly.  The most comprehensive have been by the IPCC (Inter-governmental Panel on Climate Change).

The IPCC in 2007 stated that global warming is occurring, and it is highly likely (90% probability) that humans are causing it.  (Here I will not go into the science behind these judgements, because this is precisely where the debate gets deflected from the one we should be having.)

Can the IPCC judgements be trusted?

Not entirely.  Their conclusions were vetted by politicians and some of the more challenging conclusions were removed at the insistence of China, the US and other countries with big vested interests in fossil fuels – that’s why it’s called an inter-governmental panel.  Their process was also rather slow and conservative, so even the un-vetted conclusions may have been dated and too conservative.

Many climate scientists soon pointed out that the situation is likely to be worse than portrayed in the 2007 IPCC report, though that is not the bias climate sceptics usually mention.  Also some sceptics challenge the IPCC’s use of probabilities, without making clear that they are an attempt to clarify the meaning of qualitative terms like “likely” and “highly likely”.  They are attempts to convey the reliability of the judgements, not the science.

Nevertheless the IPCC message is clear and alarming (the news is alarming, not the messengers).

How certain should we be before we act?

The response of the climate system to greenhouse gas emissions is delayed by two or three decades.  By the time we agree the uncertainty is acceptably low, it will be too late.  We must, if we are to avoid disaster, act before we have reasonably complete knowledge.

Our politicians do that all the time, and with far less evidence, on many important topics.

What are the costs of reducing greenhouse gas emissions?

If we are causing global warming through our emissions of greenhouse gases, which of the following options best conveys the cost of reducing and eventually eliminating those emissions?

a)  it would wreck most countries’ economies

b)  it would be a substantial but bearable cost

c)  it would be a minor cost

d)  it would save more money than it would cost

You may be surprised to learn that many economists these days would say (c), though  some diehards cling to (b).  Many environmentalists say (b), and point to the moral imperative to sacrifice, but they could be better informed.  Many fossil fuel companies and other vested interests promote the myth of (a).  (Well, you could wreck economies by going about it the wrong way, like relying on “clean coal” and other such distant, expensive, risky and uncertain fantasies.)

However most economists are not actually very knowledgable about technology or business (or many other things you’d think they ought to know about).

A minority of economists, business people, technologists, town planners, etc. point out that many better designs, technologies and ways of organising our societies already exist that dramatically cut greenhouse gas emissions while saving money, or at a cost that is a very sensible investment.  People who assess the prospects of this approach argue that emissions could be reduced to near zero by 2050 at small or negative cost (eg. RMI, Circular, and many other studies).  They assume only present technology or modest and plausible developments of it – technology is not the limitation.

So the best answer is

no more than (c, a minor cost), but (d, a saving), if we do it right.

What if we do nothing, or not enough?

At some point global warming is likely to run out of control and ramp up to 4, 6 or more degrees Celsius (at present it is about 0.8°C), because natural processes like release of gases from warming tundra kick in and tip it into runaway warming.

We don’t really know where the tipping point might be.  New science is suggesting it might be below 2°C of warming.  It could conceivably be happening now, for all we know (those uncertainties again).  James Hanson thinks we should limit warming to no more than 1°C, and bring it down quickly even from that.  That would, by now, be a big but not impossible challenge.

What are the consequences of doing nothing, or not enough?

I did not ask what are the costs, because the consequences go far beyond any meaningful dollar values.  The consequences go far beyond a few extra heat waves, fires, storms and floods.  The Earth would become an unfamiliar place, unlike anything since our fragile civilisation began around 10,000 years ago.  Here are a few plausible possibilities.

The Great Barrier Reef an early casualty (it may already be too late).

The present global industrial system another early casualty (victim of severe weather, disrupted supply lines, peak oil, political disruptions, and its own internal fragility among other factors).  Real hardship for many people, with rising death rates.

Half the world’s cities flooded within 100-200 years, and continuing sea level rise for centuries.

Food production dramatically disrupted, resulting in millions, possibly hundreds of millions, conceivably billions of deaths.

Up to half of the world’s species extinct.

On the way to those extinctions, severe disruption of ecosystems resulting in plagues and pandemics.

Wars over territory and dwindling resources.

A dark time for humanity.

What would be left?

Life on Earth would certainly survive, though diminished by a significant mass extinction.  Humans would survive, though in an impoverished world.  Settled communities would be challenged by continuing climate instability, probably for thousands of years.  A much diminished form of civilisation might survive, though not with certainty.  Global inter-dependence would be severely weakened, local economies would be necessary.  Of the current richness of human culture and knowledge, who knows?


So there you have it.  The risk is high and the consequences potentially catastrophic or apocalyptic.  That is the best judgement of those best-placed to know.

The cost of avoiding disaster is not large, but we have to act soon.  We just have to be willing to change many of our current habits.  The good news is that we can solve all the other global crises at the same time (peak oil, peak water, depleting soil, depleting forests etc.) if we do it right.  The further good news is that our health would improve, and we can focus on living more satisfying lives than just accumulating stuff.

The best news is we would avoid catastrophe and pass a still-rich and wondrous world to our grandchildren.

15 thoughts on “The Productive Way to Address Global Warming

  1. Peg Job

    I like this clear explanation very much Geoff. I wonder if you are aware of the excellent you might consider publishing this there.


  2. Kevin Cox


    Perhaps you do not want to be accused of scare mongering but isn’t the most likely scenario of the do nothing scenario is that life as we know it disappears as the temperature rises to the boiling point of water.


  3. Geoff Davies Post author

    Kevin –
    The Earth seems to have a series of buffers that will kick in and limit any runaway (though not before our way of life has been considerably disrupted). So hopefully it’s extremely unlikely that all of those buffers will be over-ridden and we’ll end up like Venus, cooked.

    Thanks. I’m trying it somewhere else first, but good suggestion.


  4. Greig

    “The IPCC in 2007 stated that global warming is occurring, and it is highly likely (90% probability) that humans are causing it.”

    So climate scientists agree that AGW is real. But is there consensus on how much of observed warming is caused by humans? And is there agreement that climate change will be catastrophic, or even bad? Sorry Geoff, you article does not address those fundamental points.

    Further, you declare that there are tipping points. There is certainly no more than a cursory support for that view within the peer reviewed literature on that point, and the IPCC apparently does not agree with you.

    Unfortunately, whilst the article starts with the right question, it leaps progressively from the sublime to the ridiculous and provides no supporting references for its many alarmist claims.


  5. Geoff Davies

    Loose paraphrasing in my part. I could more accurately have said “that humans are the main cause”.

    Tipping points – a quick Google search reveals , that lists many of the dozen or more possible drivers. They are well supported in the peer reviewed literature and well recognised among climate scientists.

    Positive feedbacks (that can lead to tipping) are explained further at and

    The Wikipedia entry on feedback quotes the IPCC: “Anthropogenic warming could lead to some effects that are abrupt or irreversible, depending upon the rate and magnitude of the climate change.” The IPCC, overseen and censored by governments, was very cautious but still pointed to the potential for runaways.

    There is a large academic literature on the consequences of climate change, as you can easily discover by Googling “consequences of climate change”.

    None of your claims withstands even cursory checking.

    As usual Greig you resolutely refuse to do anything to remedy your ignorance, though it would be easy to do, as I have just done. As usual I conclude you are more interested in harassment than in learning. I’ve blocked you before and I’ll do it again if you persist.


  6. Greig


    Thanks for your response.

    You Wiki articles cannot remedy any perceived ignorance, since I am quite aware that there are POTENTIAL climate tipping points. I am merely stating that the reality of CO2 emissions actually reaching/exceeding such a tipping point is not well supported in the peer review literature. And as you have acknowledged, is not supported by the IPCC.

    It is very obvious that many advocates of climate alarm correctly declare the support of the vast majority of climate scientists for AGW being real (as acknowledged by the IPCC), but then disingenuously extends that fact to declaring that climate scientists support a conclusion that AGW will be catastrophic and therefore urgent action is required regardless of the cost. The above article demonstrates this false dichotomy.

    Thanks again for your response and article.


  7. Geoff Davies Post author

    Just to correct the usual misrepresentations Greig perpetrates:

    The possibility of actually reaching tipping points is well-acknowleged in peer-reviewed literature

    IPCC’s words (above) clearly acknowledge the possibility of runaways, as anyone but Greig can see.

    AGW potentially catastrophic – already covered.

    All of the major relevant scientific societies have made clear statements that actions to reduce AGW should urgently be undertaken. Stop wasting this space Greig.

    “regardless of the cost”. As Greig well knows, and my article repeats, I argue the costs of avoidance are not great. He doesn’t believe this, and simply reframes my argument through his distorting lens.


  8. Greig


    Thanks again.

    But you know that the “possibility” of “potentially” reaching tipping points being acknowleged in peer-reviewed literature, does not suggest that it is considered likely, nor does it imply that such a likelihood has the consensus support of climate scientists. Tipping points are actually considered outliers in climate science.

    Hal Lewis resigned because scientific academies around the world were expressing weazel words in their rush to not be singled out as “deniers”.

    Indeed, I do believe the cost of reducing emissions are very high. Your assurances otherwise have not convinced me, nor apparently anyone else in the world, as evidenced by the Copenhagen conference outcome.

    As always, Geoff, an interesting discourse.


  9. Geoff Davies Post author

    You never cite any sources for your bald assertions, though you demand complete documentation from me. Enough of this nonsense.


  10. Greig

    Sources for bold assertions:

    Tipping Points: Excellent paper here:
    “… the IPCC states that tipping points and thresholds are poorly determined (O’Neill and Oppenheimer 2002; Lowe et al. 2006; Corfee-Morlot and Höhne 2003) … the IPCC ultimately concludes in their assessment that some of these systems, such as the melting of the Greenland Ice Sheet and changes in the AMOC, are unlikely to reach their tipping point within the 21st century (Meehl et al. p. 818). … “future abrupt changes cannot be predicted with confidence” because of the insufficiencies of current climate models, which are, to a large extent, a reflection of limits of present understanding.”

    “While the current research has alerted scientists to potential large events, continued monitoring, research, and modeling will be required, especially of the systems that have greater potential impacts, in order to produce specific recommendations for policy decisions.”

    Geoff, please note the extensive reference list at the end of this article. Were they all paid by the fossil fuel industry?

    On Hal Lewis:


  11. Geoff Davies Post author


    You’re doing a great job of the usual distraction and confusion. The very small minority of climate scientists who think humans are not causing GW (e.g. Richard Lindzen) has not been able to convince the rest of their colleagues. It is dead easy to feed a virtually-unlimited stream of misconceptions, misinformation and disinformation into the discussion and keep it confused indefinitely. Scientists have a way of filtering out most of this garbage, and they do not share your conclusion.

    I told you IPCC was cautious. Tipping points are difficult to pin down, even if you know they’re there in a model system.
    btw a four degree increase was the subject of papers here

    Of course it’s all rather uncertain. Read my piece again. The question is risk: probability plus potential magnitude of consequences.

    I never heard of Hal Lewis, but if he, and you, are guided by Monckton and “Climategate” then you are sadly misled.

    No more such comments on this post.


  12. Greig

    Message to Geoff.

    You may declare that my intent is to distract and confuse. But I am actually trying to get to the crux of this issue. Your argument is that AGW is real (the experts agree), so therefore we must take action. There is a bit missing in the middle which is worthy of discussion. What is the actual risk of serious consequences? You dismiss this, stating “These risks are not quantifiable”. And you declare that reducing emissions is cheap, that the cost-benefit equation supports taking action, though the experts in that field are far from reaching consensus.

    As long as you continue to simplify the debate down to “climate scientists agree that AGW is real, therefore we are all doomed.” you will fail to convince those of us with enough intelligence and education to seek to understand and quantify the deeper issues that are important in formulating policy.


  13. Geoff Davies Post author

    Greig, here’s something you don’t seem to have grasped: I’m not trying to convince you, it’s not worth my time. That’s why I don’t comprehensively reference everything all the time, nor answer your every query, and why you shouldn’t take my unwillingness to do so as a victory for you.

    I speak rather to those more receptive than people like you. I only comment on your comments so the misinformation you bring doesn’t go unchallenged here. If you have “enough intelligence and education”, and an open enough mind, then spend several years or more properly studying the science and how science works before presuming to know better than people who have spent their lives studying these things.

    You, again, oversimplify my views and minimise the evidence for the dangers resulting from global warming. Regardless of your intention, the effect of your comments is to distract and confuse.


  14. Greig

    Geoff, here’s something you are not understanding. I don’t need you to educate me. I have spent over 25 years studying this subject. I am trained in science at a tertiary level. You keep speaking down to me as if you are more qualified than myself, but you are not. I am not the one presenting misinformation, rather informing those who would otherwise be “receptive” to your arguments, the logical fallacy in your presentation, your oversimplification of the scientific basis for “dangerous” climate change, and the lack of evidence and lack of expert support (not for AGW itself but rather) for your alarmist views.

    I understand that from your viewpoint you may see this as an attempt to “distract and confuse”. From my viewpoint, it is an attempt to discuss and debate. I would have thought that is what this blog would have been for? Perhaps I have misunderstood the purpose of this website?



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