By Brian Davey: Limits to Economic Growth?

These notes from a lecture recently given by Brian Davey are a very nice primer and refresher on limits to growth.

The most interesting thing about limits growth is that it is, by far, the most important issue we should be discussing as a species, yet it is pretty much the only issue that we never discuss.

Denial is amazing!






This diagram by Charles Hall (and reproduced in my book Credo) can be thought of as illustrating the idea of the techno-fix transition if it were possible. It shows two diagrams of the economy and energy system in 1970 and 2030. There are no figures – the point of the pictures are to show the way that more energy is extracted out of the global system and then used in the global economic process between the two dates – and to show the different proportions in which the global economic output is divided up. Although more energy is being used at the later date a much higher proportion of the output of the society has to take the form of investment goods – machinery, equipment and infrastructure – with a smaller proportion in the form of final consumer goods. The higher machinery, equipment and infrastructure has to be applied to extracting energy because more resources are needed for pollution and waste control, for reducing greenhouse gases, for coping with the depletion of energy minerals, for investing in energy sources like solar or biofuels that give a very low energy return on energy invested and to cope with intermittency. In other words – the higher investment in energy does not mean higher output of energy – it is necessary to cope with the declining efficiency, declining returns of the energy system past the limits to growth.

Since a large proportion of total production is being devoted to investment goods to cope with depletion and pollution, less is left over for consumer goods and particularly for discretionary consumer goods – luxuries, the goodies of a consumer society. But what consequences would this have? As people have to pay more for clean energy they would have less for the knick-knacks on sale in the luxury shops in airport lounges, if indeed people could any longer afford to fly. The argument here is that this would be crushing to a consumer society and there would be a permanent recession in the consumer goods sectors – indeed there would be a political crisis in such a society.

In summary, the theorists of 1972 argued that growth would run out as more and more resources would have to be devoted to the work arounds and techno-fixes to deal with depletion and pollution. They did not deny that techno-fixes would be available – what they were drawing attention to was that adopting them would take resources away from growing production to fixing the problems. Eventually fixing the problems would become too expensive so industrial production and food production would turn downwards. They were right. That’s exactly what is happening…

18 thoughts on “By Brian Davey: Limits to Economic Growth?”

  1. If I pedal a generator at 70W, it takes 42 hours to generate 3 kHw. Maybe you meant to say “3 kWh per week”, instead of “p/day”. I hope the rest of your calculations are more accurate, but cannot so easily verify them. I’ve also read that an adult can crank 100W for 10 hours a day, a nice round 1 kWh. So, as a professional turner of generator cranks, my time would be worth about 1.5 cents per hour. Another figure that I’ve heard is that a gallon of gasoline contains the energy of 240 hours of human labor. Regardless of the details, we will be truly fully fracked as oil becomes more expensive.


    1. Thanks for pointing out an error in Brian Davey’s calculation. I did not check his calculations because I’ve read enough similar arguments to know he is in the ballpark . Using your estimate of 100W for 10 hours a day, and assuming Davey’s other numbers are correct, this means we enjoy 3 times the number of energy slaves that Davey’s claims, which makes an even stronger case for the severity of human overshoot.


    2. Disagree. David MacKay in his book Sustainable Energy Without The Hot Air estimated the UK energy consumption to be 200 kWh per day per person. His book can be read online for free at

      1 kWh/day will light a 40W light bulb for 25 hours

      The last time I calculated it, the UK produced less than 2 kWh per day per person from renewables.


      1. just to make myself clear. I disagree with the figures of original article that calculated the energy consumption of a US person as 612 kWh/day (204 x 3 kWh/day) and a UK person as 330 kWh/day (119 x 3 kWh/day) and agree with Lathechuck


        1. Assuming MacKay’s consumption numbers are correct and assuming Lathechuck’s estimate of human labor is correct we arrive at 200 energy slaves per person in the UK. Which is twice the number estimated by Brian Davey, which only strengthens the argument he is trying to make. What is the point you are trying to make?


          1. No point really just an observation. Each of us use about 200 kWh/day in the UK but less than 2 KWh/day was obtained from renewable sources in 2016. Net energy from fossil fuels will be close to zero by the end of this century by my reckoning. Therefore even if renewables were to go through 4 doublings (which is very unlikely)from 2 to 4 to 8 to 16 to 32 kWh/day each (also assuming our population remains constant, which it won’t also) renewables would not produce anywhere near the amount of energy that we currently consume.

            Out of the 32 kWh/day each we would have to reserve maybe 8 kWh/day each to renew the renewable (assuming a very optimistic energy return of 1:4 (1/4of 32=8)). Storage and transmission of the electricity would reduce this further. Therefore the very very optimistic outlook for our energy production beyond the end of the century is about 20 kWh/day each.


            1. Yes, we have a really big problem. Isn’t it remarkable that this is not even whispered about as an issue in elections? Or on the front page of newspapers. Or taught in schools? What could possibly be more important for us to acknowledge?


              1. Many call it a predicament rather than a problem – a problem without a solution. This is the main reason that most people can’t deal with it and prefer to deny that it exists instead. By the end of this century we will be back to being an agrarian society whether we like it or not. The only choice we have left is whether we engineer a soft transition or a crash transition.

                Liked by 1 person

                    1. I was being sarcastic by the way, but summarises how most people think. Short term rewards trumps long term consequences. Ever wondered why 67% of people are overweight for example?


                    2. Given that most of our “wealth” is debt, and given that debt needs growth to retain its value, reasonable people might disagree on whether we should try to shrink the economy in a planned and civilized manner, or take our chances with a future crash. What fascinates me is that we do not even the debate the options. In fact most people don’t even know what the options are.


                    3. Keep up my eating analogy. Most people accept that eating too much is bad for their long term health but they continue to do so. The issue gets debated all the time but makes very little difference. So the question is, why?

                      It must be programmed into our genes. We need to maximise our energy intake (food) at all times to maximise our survival chances in the short term. This can be extended to the National scale. A Nation needs to maximise its energy consumption at all times to maximise its survival chances in the short term too. A Nation who doesn’t do so is vulnerable to take over by other stronger Nations.

                      ps You are confusing money with wealth. Wealth is stored energy and resources while money is a human construct, created as debt in our fiat system, that is used as a claim on future energy and resources.


                    4. Most people don’t even know or have a sense of the severity of the problem. Although the basics of limits to growth and pollution are not that difficult to understand, it requires abstract thinking, thinking in a systems perspective, and analysis of much data to get the details.
                      But there is no public talk about our predicament. The consequences of our current trajectory would have to be made clear to people in simple terms and on a personal level.
                      There is talk about sustainibility and our renewable future in the energy sector, automotive sector, etc. and also talk about Co2 and climate agreements. But I don’t think most people know how serious and immediate these problems are; they tend to think things will go on as in the past, but don’t seem to be aware that if the abovementioned plans don’t work out (and they won’t), it’s game over.
                      The peak of conventional oil 2010 is mostly unknown to the public, population & economic growth is not discussed/condemned, and climate change is pretty much out of control already, certainly if we keep going.
                      We know why this is not being talked about in public. Leaders are in denial or have realized that it is too late to change course, our debt based financial system requires growth, therefore discussing our predicament publicly would only hasten collapse. Nobody wants to risk that.


                    5. The future will be bad. I think we could choose to make the future less bad. Most overshoot aware people I know think we should party on and enjoy whatever time we have left. I disagree.


                    6. 5 stages of grief when confronting a loss. In our case, the loss of our finite fossil energy legacy.

                      Denial, Anger, Bargaining, Despair, and Acceptance. To this I add a pre-stage: ignorance.

                      We are all at different points in the process, Rob. I’m personally at the last stage.


                  1. Hi Chris. The course being followed by the establishment at the moment is keeping the unsustainable going for as long as possible. If too many people knew about our predicament they might lose control.


    3. Thanks for setting me right on the maths – I was a bit slap dash on that. My aim was to convey a general idea of what the energy/ work that the human body can generate compared to a society based on powered maachinery. If you go into the concept of energy slaves in more depth it gets more complicated – because the body at rest also requires energy. According to this article “In first approximation, a body working hard will use about 5 kWh of food per day.” which is much more than my 3kWh a day


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s