Growth Has an Expiration Date

Just a quickie.  A few weeks back, I tried to cram four Do the Math posts into a 20 minute talk, delivered at the Compass Summit.  For those of you who would rather watch 23 minutes of video than sit down to read four posts, here is a link to the video of the talk.  Perhaps you’ll see why I should stick to writing.

Growth Has an Expiration Date from Compass Summit on

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13 thoughts on “Growth Has an Expiration Date

  1. Hi Tom,
    Just watched your talk. Good job. That’s a lot of material to cover in just 20 minutes. A little rough around the edges but a few more runs and you’ll be as smooth as Al Gore 😉
    Keep you blog going. It gives me hope that someone else is thinking the same things. Now, if we can convince everyone else to start thinking…

  2. Thanks for the video. For the sheeple, every word from an entertaining speaker is worth a thousand words in print. While priorcreading the posts in your blog were definitely helpful, the talk itself was a good synopsis. And while the writing is most definitely worthwhile, one may have to do as television does, and aim at an 8th grade (or lower) level if one wishes to hit the bulk of the sheeple. And in that case the visual cues are essential. Practice, however, makes perfect.

  3. Tom, Your writing is great and the video lecture was very good. With the credentials you have, please please find a way to do more video presentations. I am quessing that I am part of the, say 5%? 2%? of the american public acutely aware and concerned (frankly terrified) of energy/economic slow mo train wreck I see occurring this decade. I am amazed how many intellegent politicians, businessmen, engineers don’t even have this on their radar yet, let alone the man on the street. I was hoping for a “manhattan project” kind of focus of government funded science research on things like algeaoil, ocean wave/tidal energy producing anhydrous amonia for liquid fuel, even coal to liquids to help tide us over. But until a crisis is recognized, there is no action taken.
    I’ ve written politicians, written, argued, and passed resolutions before the WV electoral degations but can get no politician to take action or even listen with half an ear….I’m a figurative sculptor, not a physicist from cal tec.

  4. Brilliant talk. You hit all the important points. Thanks.

    I am struggling to understand the implications of efficiency gains. You argue that we might continue to grow faster than energy availability via efficiency gains.

    Dr. Timothy Garrett argues that increased energy efficiency leads to faster growth which results in higher energy consumption (aka Jevon’s paradox).

    Can you please elaborate a bit on energy efficiency?

    • Yes, Jevons’ paradox is a nasty bit of work. Buy a more efficient refrigerator, and put the old one in the garage to keep a bunch of beer cold. But more generally, as you point out, increased efficiency lubricates growth, increasing overall demand. But it’s still growth. More activity, more service (even if a sensitive soul would deem it wasteful). So increased efficiency lets us do more with the same amount of energy (or do a whole lot more with a little more energy). Whatever the case, efficiency will contribute to growth—and efficiency limits are capped, so this form of growth is capped. This is really the main point I wanted to make.

      • I have read it somewhere (long lost in the mist of time) that Jevon’s paradox doesn’t apply at a macro level when limits to growth in primary energy supply are reached. I recall that the argument was a fairly cogent one, but it didn’t come with any numbers attached. It is intellectually (and morally) appealing that after the peak in primary energy supply, efficiency gains might be spent on increasing equality – that is shared with the community rather than spent on the beer fridge in the garage. Can you think of a thought experiment that works the numbers to explore how such an outcome might come about?

  5. I just wanted to let you know that, despite your worry that “Perhaps you’ll see why I should stick to writing”, you’re a fantastic speaker: Clear, humble, concise, convincing, and brilliant. Thanks for the video. I’m going to try to get as many people to watch it as I can. 🙂

  6. Great job on this! Your points/slides on growth in energy-consumption and the power of exponentials are compelling and well presented.


  7. What an excellent blog. Thanks for your contributions.

    I’m interested in what you think a sustainable population would be, and what birth rate you calculate would be required to reach that limit in a reasonable time. My preliminary calculations say a birthrate of 1 per couple would be needed for the next 25 years, which is troubling. See .

    • The level of sustainable population really depends on what standard of living you want and the level of environmental degradation you can tolerate. In order for the whole planet to provide the lifestyle enjoyed in the “developed world” (think North America, Europe, Australia, Japan , etc) without any further environmental degradation I have seen estimated ranging from 300 million to 1 billion. But there are a lot of assumptions and cveats surrounding those numbers.

      As to reducing the population, China has been doing that for two(?) generations now and looks like continuing for at least another two. Don’t forget that even with that kind of behaviour there is a considerable time lag before the population peaks and then declines.

  8. I work and teach in the renewables and sustainability fields (mainly) and I have been banging on about this for years. Some people get it, but many don’t. The most frustrating and depressing response I get is something like “Oh yes, I understand all that, but it can’t apply to the planet because it’s..well.. so big!” But, like you, I take heart in each person who does “get it”.

    But, when you see the tell tale signs on peoples faces as they start to appreciate how our societies are so dependent on all this “growth” and the implications of it not being there, it is marvelous transformation to watch.

    Great blog

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