7 ms·

Energy and Human Ambitions on a Finite Planet

55 points by eleitl 5y ago

pdonis 5y ago
The basic M.O. here is not new: (1) Present the basic math of exponential growth to show that exponential growth cannot continue indefinitely; (2) claim that sustaining our present lifestyle would require exponential growth to continue indefinitely; (3) conclude that our present lifestyle cannot be sustained. The issue, of course, is in step 2.
- chordalkeyboard 5y ago
  what's the issue with step 2? Our present lifestyle does seem to require constant growth, and if this is not the case it would be nice for someone to explain how we can keep getting more out of the system without contributing more to the system.
  - danbruc 5y ago
    Why does our current lifestyle require constant growth, could we not just stop at our current energy consumption level?
    - chordalkeyboard 5y ago
      lots of reasons but population growth and our dependence on technology are two of the major ones.
      - danbruc 5y ago
        I was about to add ignoring population growth to my comment because developed countries are generally close to replacement-level fertility rate and I don't think having more children is part of or current lifestyle. Also lifting everyone to the living standard of highly developed countries will require significant amounts of resources and significantly increase energy consumption, this however is also more like a one-time expense and I would therefore ignore it, too. How does dependence on technology demand growth? Because resource extraction becomes less efficient as we deplete available sources?
        chordalkeyboard 5y ago
        > I was about to add ignoring population growth to my comment because developed countries are generally close to replacement-level fertility rate and I don't think having more children is part of or current lifestyle. actually they are generally below replacement level, which (if not augmented by immigration) would itself lead to a collapse as people leave the workforce and there are fewer laborers to replace them. But people think we manage this labor shortage with technology, which leads us back to the requirements for more energy and capital development to maintain the same lifestyle. > Also lifting everyone to the living standard of highly developed countries will require significant amounts of resources and significantly increase energy consumption, this however is also more like a one-time expense and I would therefore ignore it, too. why do 'highly developed' countries need vastly greater resources to maintain this living standard if its a one-time expense? the greater standard of living your referring to requires continually expanding quantities of inputs in terms of energy and labor, aka 'economic growth'. > How does dependence on technology demand growth? its more related to the specific technologies we've chosen to build our society upon, but this technologies generally depend on these improvements to sustain themselves. For example, electric cars require batteries which require raw materials to be mined, recycling batteries requires chemical industry that is predicated on all sorts of inputs, themselves coming from nonrenewable sources.
        danbruc 5y ago
        actually they are generally below replacement level, which (if not augmented by immigration) would itself lead to a collapse as people leave the workforce and there are fewer laborers to replace them. Which is extra good as this offsets other parts of the world. I would also guess that it is probably easier to provide incentives for people to have more children once this becomes necessary than trying to prevent them from having too many children, but that is not much more than a gut feeling. But people think we manage this labor shortage with technology, which leads us back to the requirements for more energy and capital development to maintain the same lifestyle. If we permanently fall below replacement-level fertility, we will just die out and no amount of investment will fix this. The only solution is to match replacement-level fertility which will provide a stable population and workforce and hence require a stable amount of economic activity to achieve a stable lifestyle. The obvious caveat is of course that the economic activity must not deplete any non-renewable resources. why do 'highly developed' countries need vastly greater resources to maintain this living standard if its a one-time expense? the greater standard of living your referring to requires continually expanding quantities of inputs in terms of energy and labor, aka 'economic growth'. The one-time expense is to lift someone from say 2,000 kWh/a to 40,000 kWh/a which requires adding the difference in production capacity. After that this person will of course consume 40,000 kWh every year and we will have to produce those 40,000 kWh every year, but I don't think that constitutes economic growth. Economic output is quantified as absolute output over some period of time, not as cumulative absolute output. For example, electric cars require batteries which require raw materials to be mined, recycling batteries requires chemical industry that is predicated on all sorts of inputs, themselves coming from nonrenewable sources. I still don't see how this requires continued growth if we assume constant output.
  - pdonis 5y ago
    > Our present lifestyle does seem to require constant growth No, it doesn't. The obvious cause of the huge economic growth over the past 150 years, which is what the author focuses on, is population growth. World population is expected to level off in this century. The author also assumes, incorrectly, that GDP--money spent on goods and services--is the right measure of overall wealth. It's not. The author even discusses "decoupling", the fact that many types of wealth require little or no physical resources to produce, but fails to realize that the long term outcome of this will not be to raise monetary GDP more and more, but to make monetary GDP less and less of an accurate measure of wealth production. Finally, the author misunderstands basic economics when he says (p. 25): "A limited life-essential resource will always carry a moderately high value." This is a common misconception. An obvious counterexample is air: air is a limited resource (Earth's atmosphere contains only a finite quantity of it), it is life-essential, but it is free. Why? Because it costs nothing to produce. And if the cost of production of other life-essential resources, like food, were reduced, those things would also become cheaper. (In fact, that has already happened to a large extent in the developed world: over the past 150 years, the fraction of people involved in food production has dropped from about 19 in 20 to about 1 in 20. The main reason food is not much cheaper as a result of this is political: governments artificially manipulate the markets for food, for example by paying farmers not to grow certain crops. This is fixable without any increase at all in our expenditure of physical resources.)
    - chordalkeyboard 5y ago
      > No, it doesn't. The obvious cause of the huge economic growth over the past 150 years, which is what the author focuses on, is population growth. World population is expected to level off in this century. world population is leveling off because we're approaching many of these limits to growth and that's affecting the enabling factors for continued population growth. > The author also assumes, incorrectly, that GDP--money spent on goods and services--is the right measure of overall wealth. It's not. The author even discusses "decoupling", the fact that many types of wealth require little or no physical resources to produce, but fails to realize that the long term outcome of this will not be to raise monetary GDP more and more, but to make monetary GDP less and less of an accurate measure of wealth production. I agree with this. > "A limited life-essential resource will always carry a moderately high value." This is a common misconception. An obvious counterexample is air: air is a limited resource (Earth's atmosphere contains only a finite quantity of it), it is life-essential, but it is free. Why? Because it costs nothing to produce. you conflate value and price here. obviously atmosphere is not currently metered. That doesn't mean we don't place a high value on clean air. > And if the cost of production of other life-essential resources, like food, were reduced, those things would also become cheaper. https://en.wikipedia.org/wiki/Jevons_paradox https://en.wikipedia.org/wiki/Jevons_paradox
- arrosenberg 5y ago
  Author even acknowledges it on page 27, but thinks this time Malthus must be right.
- adamsmith143 5y ago
  https://en.wikipedia.org/wiki/The_Limits_to_Growth https://en.wikipedia.org/wiki/The_Limits_to_Growth Figured this out decades ago.
makerofspoons 5y ago
"Salvaging a decent future requires keen awareness, quantitative assessment, deliberate preventive action, and—above all—recognition that prevailing assumptions about human identity and destiny have been cruelly misshapen by the profoundly unsustainable trajectory of the last 150 years." Brilliantly said. I believe a lot of resistance to the idea that our way of life is unsustainable stem from grief that the future that we were "promised" by the last century of media and marketing isn't coming. The first step towards adapting to the imminent collapse of the high-consumption lifestyle due to energy and resource limitations is to process this grief.
- ben_w 5y ago
  The way you’re phrasing that gives me a certain impression of your beliefs about what is and isn’t sustainable that may not be warranted, so I should ask explicitly: What do you think a sustainable way of life looks like? In terms of both global population size and typical life experiences.
  - makerofspoons 5y ago
    To me a sustainable lifestyle would be one where if every person alive today's annual consumption was at the same level humanity’s demand for ecological resources and services could be regenerated over the course of that year- effectively balanced. I'm a fan of Earth Overshoot Day and their approach to this problem so I am using their definition: https://www.overshootday.org/about-earth-overshoot-day/ https://www.overshootday.org/about-earth-overshoot-day/. A sustainable way of life therefore looks like the average life of someone in Bangladesh, Sri Lanka, Nepal etc. I'm not holding up the average lives of people in these places as ideal (and I'm not considering anything other than consumption) but instead realistic about what level we can consume at with our current level of technology. Within that consumption envelope we need to figure out how to improve healthcare and education outcomes. That's why I expect we're headed for tragedy- we can't and won't collapse everyone's consumption to that level. The people who consume the least will be the most hurt by the ecological consequences of what we in the high-consumption regions of the world do.
Retric 5y ago
This is filled with a lot of hand waving bad math, which distracts from some reasonable points. rule of 70tells us that the time it will take a system or collection to double in size is 70 divided by thepercentage growth rate. The time units depend on how the time over which percentage growthis expressed—like 2%per dayor 2%per year, for instance. The rule works most accurately forsmaller growth rates, under 10%. Actually showing 1.10^7 = 1.949 vs 1.01^70 = 2.007, so you can approximate by dividing percentage by 70 between 1% and 10% is fine. Stating it as true in the text then adding a note well no not actually latter on is problematic.
- zaphod4prez 5y ago
  Sorry if I’m missing something, but… what’s the problem with that quote? That’s a widely-used heuristic that helps to estimate doubling times without using a calculator (see [the Wikipedia entry](https://en.m.wikipedia.org/wiki/Rule_of_72 https://en.m.wikipedia.org/wiki/Rule_of_72). He does walk the reader through a lot of “back of the napkin” math, in order to help the reader get an intuitive sense of the models he’s using. But my impression overall is that he backs those hand-wavey calculations up with more serious calculations throughout the book.
  - Retric 5y ago
    The issue is he then uses the approximations to do with math without calling them approximations. 1.10^7 is reasonably close to 2, but 1.1^21 is 7.4 which is a fair distance from 8. He goes so far as asks someone to do the approximation across several hundred years of compounding. And sure it get’s a big number but one no even close to accurate.
    - Loanor 5y ago
      You do realize the rule of 70 is used to approximate continuous compounding not periodic compounding right?
      - Retric 5y ago
fallingfrog 5y ago
Here's a fun little exercise: Open up a spreadsheet. Label the first column C for capital. This starts at 1. Label the second column T for total resources extracted. This starts at 0. Label the third column r for resources extracted this step. Label the fourth column E for extraction efficiency. Label the 5th column m for maintenance. Make it proportional to capital. Now, for each step: E is some positive function of T with a negative slope. It doesn't have to have a finite area under the curve (you don't have to assume total resources to be finite, in other words). You just have to assume that the next unit of resources to be extracted requires a bit more effort than the last one. Use E = .1*exp(-.01*T) or something like that. r = C*E m = C*k where k is any positive number between 1 and 0- .01 is a good constant to use. C += r*q - m where q is again some constant, say .2 T += r Now observe the behavior of the system. Plot the value of C over time. For the above constants you'll want to include about 3000 steps. (Edit: forgot the maintenance term)
- reedjosh 5y ago
  Because human economics in the realm of energy and or resource extraction are easily predicted by simple equations in a spreadsheet. So much so that this trivial exercise imparts real wisdom and is definitely not mental masturbation.
  - fallingfrog 5y ago
    Unfair - I didn't say that all human economics are easily predicted by a spreadsheet. It's an exercise. A starting point for discussion. As in: to start with, point out the assumption that is wrong. Rather than just insult me.
    - reedjosh 5y ago
      > Unfair Kinda I suppose. But the whole spreadsheet 'try this' trope is already unnecessarily hostile. You could put everything that spreadsheet exercise demonstrates into words. And that's my main argument too. This equation/exercise is so simple as to be useless. Human systems are multi-variate to the degree that a simple equation -- in this case showing that reliance on extractables is bad because their availability exponentially increases at the same time humans exponentially rely upon them more -- does not mean much of anything in the larger picture. This equation sidesteps human ingenuity, free market adjustments that will be made, predicted population decline in developed countries, and if the equation did apply, where on the timeline of the curve would we be. And those are just some of the criticisms of viewing the world through such a simple myopic lens.
1053r 5y ago
The entire book falls apart because of two facts, both of which are in the book itself! "Hands down, solar is the only renewable resource capable of matching our current societal energy demand. Not only can it reach 18 TW, it can exceed the mark by orders of magnitude." (Section 13.9) "We would likely not be discussing a finite planet or limits to growth or climate change if only one million humans inhabited the planet, even living at United States standards. We would perceive no meaningful limit to natural resources and ecosystem services." (Section 3.5) An energy source that is thousands of times more abundant than fossil fuels is basically equivalent to having one one thousandth the population. While I must acknowledge the truth that converting things to run on electricity will be a large engineering and logistical challenge, and that battery production must be scaled up (as well as converting some loads to run where the sun is shining), both of these challenges pale in comparison to the money part of that first quote: "exceed the mark by orders of magnitude." In other words, even if we could only store electricity at an efficiency of 1%, we'd be fine. (In actuality, we ALREADY store electricity at efficiencies over 80 times that.) Ecosystem services, availability of raw materials, and many other challenges exist as well. However, all of them are meaningless in the face of "we would perceive no meaningful limit to natural resources." Having an energy source that is thousands to millions of times more abundant than the ones we use today lets us substitute energy for basically all of our needs. (Need clean water? Energy + dirty water = clean water. Need more steel? Dirt + energy = steel. Need to remove CO2 from the atmosphere? You can do it, at only the cost of several times the energy you got putting the CO2 into the atmosphere, which is only a few % of the future energy budget from solar. Think of it this way. In the past, we relied on cutting down forests for heat. Putting the forests back would have seemed like an insurmountable task, because our fuel came from the forests. But now that we run on fossil fuels, which are approximately 100x more abundant than forests, putting the forests back is a matter of politics and land usage discussions, not one of practicality.) In other words, we are the only ones we have to blame if the future is not MUCH wealthier than the past, both per person and also for our total economy.
- justbrowsingthx 5y ago
  I'm not sure I understand your point. Perhaps you disagree with the author on the desirability of a future in which virtually unlimited energy is available to humankind in its current state (see the upshot on nuclear fusion p. 269, for example). His cautious take on our collective ability to manage our energetic needs[0] does not seem unwarranted to me. Regardless, I think the book remains useful for its intended audiences as a quantitative assessment of available energy sources given our growth path. [0] "The rookie mistake here is assuming that adults are in charge." (p. 134)
ben_w 5y ago
> 18.4 Fermi Paradox Explained? I’m currently leaning in this direction myself. Not necessarily just this, but “big filter ahead” (or lots of small filters). Perhaps it will be this, perhaps it will be a Jonestown massacre but with entire O’Neill cylinders instead of individual people, leading to a Kardashev II scale Kessler syndrome.
westcort 5y ago
I like the last chapter, which shows some strategies for reducing energy use.
ZeroGravitas 5y ago
I feel like the author may have posted this to HN before, at least I remember a similar, book length take on this topic.
f0e4c2f7 5y ago
Ctrl+f fusion. > "Fusion is therefore a complicated and not particularly cheap way to generate electricity. Meanwhile, we are not running terribly short on renewable ways to produce electricity: solar; wind; hydroelectric; geother- mal; tidal." Fusion is the key to long term success for humanity. It paves the way to essentially unlimited cheap burstable power. In the even longer term plasma fusion offers a way to create the heavier elements that we are running out of here on earth. Forged in a manmade nuclear furnace. These pesky climate problems can be solved. We just have to mine ideas out of nature now instead of minerals. If you're trying to think about humanity's long term prospects fusion should be the crown jewel, not an after thought you handwave away. I believe today we spend somewhere on the order of 1% of what we should be spending on fusion research.
- bsedlm 5y ago
  disagree essentially because I believe we'd get into a situation where the problem becomes heat dissipation. the problem is the human psique, not technological capabilities.
  - stouset 5y ago
    If we find a cheap new way to generate orders of magnitude more energy, we'll use orders of magnitude more energy. And you're right. We're only a bit over two hundred years away at 2.3% annualized growth in energy use from noticeably raising Earth's surface temperatures just from a thermodynamic perspective. And that's completely ignoring the effects of greenhouse gases.
    - saiya-jin 5y ago
      You and parent project this in some theoretical universe where these effects would be ignored. Why on earth do you think so? With semi-unlimited energy at our palms, we can do serious geoengineering. We can put these furnaces into high orbits, or moon and beam down just raw output energy with lasers. Or whatever, even the sky isn't a proverbial limit.
deleted 5y ago
[deleted]
notRacistSir 5y ago

55 points by eleitl 5y ago

The basic M.O. here is not new: (1) Present the basic math of exponential growth to show that exponential growth cannot continue indefinitely; (2) claim that sustaining our present lifestyle would require exponential growth to continue indefinitely; (3) conclude that our present lifestyle cannot be sustained. The issue, of course, is in step 2.

chordalkeyboard 5y ago
what's the issue with step 2? Our present lifestyle does seem to require constant growth, and if this is not the case it would be nice for someone to explain how we can keep getting more out of the system without contributing more to the system.
- danbruc 5y ago
  Why does our current lifestyle require constant growth, could we not just stop at our current energy consumption level?
  - chordalkeyboard 5y ago
    lots of reasons but population growth and our dependence on technology are two of the major ones.
    - danbruc 5y ago
      I was about to add ignoring population growth to my comment because developed countries are generally close to replacement-level fertility rate and I don't think having more children is part of or current lifestyle. Also lifting everyone to the living standard of highly developed countries will require significant amounts of resources and significantly increase energy consumption, this however is also more like a one-time expense and I would therefore ignore it, too. How does dependence on technology demand growth? Because resource extraction becomes less efficient as we deplete available sources?
      - chordalkeyboard 5y ago
        > I was about to add ignoring population growth to my comment because developed countries are generally close to replacement-level fertility rate and I don't think having more children is part of or current lifestyle. actually they are generally below replacement level, which (if not augmented by immigration) would itself lead to a collapse as people leave the workforce and there are fewer laborers to replace them. But people think we manage this labor shortage with technology, which leads us back to the requirements for more energy and capital development to maintain the same lifestyle. > Also lifting everyone to the living standard of highly developed countries will require significant amounts of resources and significantly increase energy consumption, this however is also more like a one-time expense and I would therefore ignore it, too. why do 'highly developed' countries need vastly greater resources to maintain this living standard if its a one-time expense? the greater standard of living your referring to requires continually expanding quantities of inputs in terms of energy and labor, aka 'economic growth'. > How does dependence on technology demand growth? its more related to the specific technologies we've chosen to build our society upon, but this technologies generally depend on these improvements to sustain themselves. For example, electric cars require batteries which require raw materials to be mined, recycling batteries requires chemical industry that is predicated on all sorts of inputs, themselves coming from nonrenewable sources.
        danbruc 5y ago
        actually they are generally below replacement level, which (if not augmented by immigration) would itself lead to a collapse as people leave the workforce and there are fewer laborers to replace them. Which is extra good as this offsets other parts of the world. I would also guess that it is probably easier to provide incentives for people to have more children once this becomes necessary than trying to prevent them from having too many children, but that is not much more than a gut feeling. But people think we manage this labor shortage with technology, which leads us back to the requirements for more energy and capital development to maintain the same lifestyle. If we permanently fall below replacement-level fertility, we will just die out and no amount of investment will fix this. The only solution is to match replacement-level fertility which will provide a stable population and workforce and hence require a stable amount of economic activity to achieve a stable lifestyle. The obvious caveat is of course that the economic activity must not deplete any non-renewable resources. why do 'highly developed' countries need vastly greater resources to maintain this living standard if its a one-time expense? the greater standard of living your referring to requires continually expanding quantities of inputs in terms of energy and labor, aka 'economic growth'. The one-time expense is to lift someone from say 2,000 kWh/a to 40,000 kWh/a which requires adding the difference in production capacity. After that this person will of course consume 40,000 kWh every year and we will have to produce those 40,000 kWh every year, but I don't think that constitutes economic growth. Economic output is quantified as absolute output over some period of time, not as cumulative absolute output. For example, electric cars require batteries which require raw materials to be mined, recycling batteries requires chemical industry that is predicated on all sorts of inputs, themselves coming from nonrenewable sources. I still don't see how this requires continued growth if we assume constant output.
- pdonis 5y ago
  > Our present lifestyle does seem to require constant growth No, it doesn't. The obvious cause of the huge economic growth over the past 150 years, which is what the author focuses on, is population growth. World population is expected to level off in this century. The author also assumes, incorrectly, that GDP--money spent on goods and services--is the right measure of overall wealth. It's not. The author even discusses "decoupling", the fact that many types of wealth require little or no physical resources to produce, but fails to realize that the long term outcome of this will not be to raise monetary GDP more and more, but to make monetary GDP less and less of an accurate measure of wealth production. Finally, the author misunderstands basic economics when he says (p. 25): "A limited life-essential resource will always carry a moderately high value." This is a common misconception. An obvious counterexample is air: air is a limited resource (Earth's atmosphere contains only a finite quantity of it), it is life-essential, but it is free. Why? Because it costs nothing to produce. And if the cost of production of other life-essential resources, like food, were reduced, those things would also become cheaper. (In fact, that has already happened to a large extent in the developed world: over the past 150 years, the fraction of people involved in food production has dropped from about 19 in 20 to about 1 in 20. The main reason food is not much cheaper as a result of this is political: governments artificially manipulate the markets for food, for example by paying farmers not to grow certain crops. This is fixable without any increase at all in our expenditure of physical resources.)
  - chordalkeyboard 5y ago
    > No, it doesn't. The obvious cause of the huge economic growth over the past 150 years, which is what the author focuses on, is population growth. World population is expected to level off in this century. world population is leveling off because we're approaching many of these limits to growth and that's affecting the enabling factors for continued population growth. > The author also assumes, incorrectly, that GDP--money spent on goods and services--is the right measure of overall wealth. It's not. The author even discusses "decoupling", the fact that many types of wealth require little or no physical resources to produce, but fails to realize that the long term outcome of this will not be to raise monetary GDP more and more, but to make monetary GDP less and less of an accurate measure of wealth production. I agree with this. > "A limited life-essential resource will always carry a moderately high value." This is a common misconception. An obvious counterexample is air: air is a limited resource (Earth's atmosphere contains only a finite quantity of it), it is life-essential, but it is free. Why? Because it costs nothing to produce. you conflate value and price here. obviously atmosphere is not currently metered. That doesn't mean we don't place a high value on clean air. > And if the cost of production of other life-essential resources, like food, were reduced, those things would also become cheaper. https://en.wikipedia.org/wiki/Jevons_paradox https://en.wikipedia.org/wiki/Jevons_paradox
arrosenberg 5y ago
Author even acknowledges it on page 27, but thinks this time Malthus must be right.
adamsmith143 5y ago
https://en.wikipedia.org/wiki/The_Limits_to_Growth https://en.wikipedia.org/wiki/The_Limits_to_Growth Figured this out decades ago.

makerofspoons 5y ago

"Salvaging a decent future requires keen awareness, quantitative assessment, deliberate preventive action, and—above all—recognition that prevailing assumptions about human identity and destiny have been cruelly misshapen by the profoundly unsustainable trajectory of the last 150 years." Brilliantly said. I believe a lot of resistance to the idea that our way of life is unsustainable stem from grief that the future that we were "promised" by the last century of media and marketing isn't coming. The first step towards adapting to the imminent collapse of the high-consumption lifestyle due to energy and resource limitations is to process this grief.

ben_w 5y ago
The way you’re phrasing that gives me a certain impression of your beliefs about what is and isn’t sustainable that may not be warranted, so I should ask explicitly: What do you think a sustainable way of life looks like? In terms of both global population size and typical life experiences.
- makerofspoons 5y ago
  To me a sustainable lifestyle would be one where if every person alive today's annual consumption was at the same level humanity’s demand for ecological resources and services could be regenerated over the course of that year- effectively balanced. I'm a fan of Earth Overshoot Day and their approach to this problem so I am using their definition: https://www.overshootday.org/about-earth-overshoot-day/ https://www.overshootday.org/about-earth-overshoot-day/. A sustainable way of life therefore looks like the average life of someone in Bangladesh, Sri Lanka, Nepal etc. I'm not holding up the average lives of people in these places as ideal (and I'm not considering anything other than consumption) but instead realistic about what level we can consume at with our current level of technology. Within that consumption envelope we need to figure out how to improve healthcare and education outcomes. That's why I expect we're headed for tragedy- we can't and won't collapse everyone's consumption to that level. The people who consume the least will be the most hurt by the ecological consequences of what we in the high-consumption regions of the world do.

Retric 5y ago

This is filled with a lot of hand waving bad math, which distracts from some reasonable points. rule of 70tells us that the time it will take a system or collection to double in size is 70 divided by thepercentage growth rate. The time units depend on how the time over which percentage growthis expressed—like 2%per dayor 2%per year, for instance. The rule works most accurately forsmaller growth rates, under 10%. Actually showing 1.10^7 = 1.949 vs 1.01^70 = 2.007, so you can approximate by dividing percentage by 70 between 1% and 10% is fine. Stating it as true in the text then adding a note well no not actually latter on is problematic.

zaphod4prez 5y ago
Sorry if I’m missing something, but… what’s the problem with that quote? That’s a widely-used heuristic that helps to estimate doubling times without using a calculator (see [the Wikipedia entry](https://en.m.wikipedia.org/wiki/Rule_of_72 https://en.m.wikipedia.org/wiki/Rule_of_72). He does walk the reader through a lot of “back of the napkin” math, in order to help the reader get an intuitive sense of the models he’s using. But my impression overall is that he backs those hand-wavey calculations up with more serious calculations throughout the book.
- Retric 5y ago
  The issue is he then uses the approximations to do with math without calling them approximations. 1.10^7 is reasonably close to 2, but 1.1^21 is 7.4 which is a fair distance from 8. He goes so far as asks someone to do the approximation across several hundred years of compounding. And sure it get’s a big number but one no even close to accurate.
  - Loanor 5y ago
    You do realize the rule of 70 is used to approximate continuous compounding not periodic compounding right?
    - Retric 5y ago

fallingfrog 5y ago

Here's a fun little exercise: Open up a spreadsheet. Label the first column C for capital. This starts at 1. Label the second column T for total resources extracted. This starts at 0. Label the third column r for resources extracted this step. Label the fourth column E for extraction efficiency. Label the 5th column m for maintenance. Make it proportional to capital. Now, for each step: E is some positive function of T with a negative slope. It doesn't have to have a finite area under the curve (you don't have to assume total resources to be finite, in other words). You just have to assume that the next unit of resources to be extracted requires a bit more effort than the last one. Use E = .1*exp(-.01*T) or something like that. r = C*E m = C*k where k is any positive number between 1 and 0- .01 is a good constant to use. C += r*q - m where q is again some constant, say .2 T += r Now observe the behavior of the system. Plot the value of C over time. For the above constants you'll want to include about 3000 steps. (Edit: forgot the maintenance term)

reedjosh 5y ago
Because human economics in the realm of energy and or resource extraction are easily predicted by simple equations in a spreadsheet. So much so that this trivial exercise imparts real wisdom and is definitely not mental masturbation.
- fallingfrog 5y ago
  Unfair - I didn't say that all human economics are easily predicted by a spreadsheet. It's an exercise. A starting point for discussion. As in: to start with, point out the assumption that is wrong. Rather than just insult me.
  - reedjosh 5y ago
    > Unfair Kinda I suppose. But the whole spreadsheet 'try this' trope is already unnecessarily hostile. You could put everything that spreadsheet exercise demonstrates into words. And that's my main argument too. This equation/exercise is so simple as to be useless. Human systems are multi-variate to the degree that a simple equation -- in this case showing that reliance on extractables is bad because their availability exponentially increases at the same time humans exponentially rely upon them more -- does not mean much of anything in the larger picture. This equation sidesteps human ingenuity, free market adjustments that will be made, predicted population decline in developed countries, and if the equation did apply, where on the timeline of the curve would we be. And those are just some of the criticisms of viewing the world through such a simple myopic lens.

1053r 5y ago

The entire book falls apart because of two facts, both of which are in the book itself! "Hands down, solar is the only renewable resource capable of matching our current societal energy demand. Not only can it reach 18 TW, it can exceed the mark by orders of magnitude." (Section 13.9) "We would likely not be discussing a finite planet or limits to growth or climate change if only one million humans inhabited the planet, even living at United States standards. We would perceive no meaningful limit to natural resources and ecosystem services." (Section 3.5) An energy source that is thousands of times more abundant than fossil fuels is basically equivalent to having one one thousandth the population. While I must acknowledge the truth that converting things to run on electricity will be a large engineering and logistical challenge, and that battery production must be scaled up (as well as converting some loads to run where the sun is shining), both of these challenges pale in comparison to the money part of that first quote: "exceed the mark by orders of magnitude." In other words, even if we could only store electricity at an efficiency of 1%, we'd be fine. (In actuality, we ALREADY store electricity at efficiencies over 80 times that.) Ecosystem services, availability of raw materials, and many other challenges exist as well. However, all of them are meaningless in the face of "we would perceive no meaningful limit to natural resources." Having an energy source that is thousands to millions of times more abundant than the ones we use today lets us substitute energy for basically all of our needs. (Need clean water? Energy + dirty water = clean water. Need more steel? Dirt + energy = steel. Need to remove CO2 from the atmosphere? You can do it, at only the cost of several times the energy you got putting the CO2 into the atmosphere, which is only a few % of the future energy budget from solar. Think of it this way. In the past, we relied on cutting down forests for heat. Putting the forests back would have seemed like an insurmountable task, because our fuel came from the forests. But now that we run on fossil fuels, which are approximately 100x more abundant than forests, putting the forests back is a matter of politics and land usage discussions, not one of practicality.) In other words, we are the only ones we have to blame if the future is not MUCH wealthier than the past, both per person and also for our total economy.

justbrowsingthx 5y ago
I'm not sure I understand your point. Perhaps you disagree with the author on the desirability of a future in which virtually unlimited energy is available to humankind in its current state (see the upshot on nuclear fusion p. 269, for example). His cautious take on our collective ability to manage our energetic needs[0] does not seem unwarranted to me. Regardless, I think the book remains useful for its intended audiences as a quantitative assessment of available energy sources given our growth path. [0] "The rookie mistake here is assuming that adults are in charge." (p. 134)

ben_w 5y ago

> 18.4 Fermi Paradox Explained? I’m currently leaning in this direction myself. Not necessarily just this, but “big filter ahead” (or lots of small filters). Perhaps it will be this, perhaps it will be a Jonestown massacre but with entire O’Neill cylinders instead of individual people, leading to a Kardashev II scale Kessler syndrome.

westcort 5y ago

I like the last chapter, which shows some strategies for reducing energy use.

ZeroGravitas 5y ago

I feel like the author may have posted this to HN before, at least I remember a similar, book length take on this topic.

f0e4c2f7 5y ago

Ctrl+f fusion. > "Fusion is therefore a complicated and not particularly cheap way to generate electricity. Meanwhile, we are not running terribly short on renewable ways to produce electricity: solar; wind; hydroelectric; geother- mal; tidal." Fusion is the key to long term success for humanity. It paves the way to essentially unlimited cheap burstable power. In the even longer term plasma fusion offers a way to create the heavier elements that we are running out of here on earth. Forged in a manmade nuclear furnace. These pesky climate problems can be solved. We just have to mine ideas out of nature now instead of minerals. If you're trying to think about humanity's long term prospects fusion should be the crown jewel, not an after thought you handwave away. I believe today we spend somewhere on the order of 1% of what we should be spending on fusion research.

bsedlm 5y ago
disagree essentially because I believe we'd get into a situation where the problem becomes heat dissipation. the problem is the human psique, not technological capabilities.
- stouset 5y ago
  If we find a cheap new way to generate orders of magnitude more energy, we'll use orders of magnitude more energy. And you're right. We're only a bit over two hundred years away at 2.3% annualized growth in energy use from noticeably raising Earth's surface temperatures just from a thermodynamic perspective. And that's completely ignoring the effects of greenhouse gases.
  - saiya-jin 5y ago
    You and parent project this in some theoretical universe where these effects would be ignored. Why on earth do you think so? With semi-unlimited energy at our palms, we can do serious geoengineering. We can put these furnaces into high orbits, or moon and beam down just raw output energy with lasers. Or whatever, even the sky isn't a proverbial limit.

deleted 5y ago

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notRacistSir 5y ago