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Power Technology

Limits On Growth of Energy Use and Economies 482

snoop.daub writes "Dr. Tom Murphy, professor of astrophysics at UCSD, has a new blog called 'Do The Math,' and the first few posts are doozies. In the first, he shows the impossibility of continued exponential growth in energy use. Even if a new, 'free' energy source is developed, thermodynamic limits on efficiency mean that the heat associated with converting this energy into useful work will increase the temperature of the earth to unbearable levels within 300 years. In the second, he extends the argument to economic growth. The timescales there are faster, only 50-100 years. Fascinating stuff. Time to stop breeding, folks, or to get our butts into space."
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Limits On Growth of Energy Use and Economies

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  • by MikeB0Lton ( 962403 ) on Tuesday August 02, 2011 @08:15PM (#36966812)
    If/when we ever get to the point that the human population is too large to be sustainable, it will correct itself. History shows us that famine, war, and plague occur when we run out of resources or populate an area too densely. Some of the strong, smart, and lucky will survive to repopulate.
  • Re:No One (Score:4, Interesting)

    by blair1q ( 305137 ) on Tuesday August 02, 2011 @08:24PM (#36966896) Journal

    Did he do this one?

    Calculate how long it will be until, at given birth and death rates, the bounding surface of the volume of human flesh on the planet will be expanding outward at a rate equal to the speed of light?

    Hint: The answer is in the low 4 figures.

  • by stereoroid ( 234317 ) on Tuesday August 02, 2011 @08:32PM (#36966982) Homepage Journal

    I'm almost all the way through it. Very sobering stuff [], only a few bits I have quibbles with. Or, if you don't have the time, read the synopsis [].

    The point about the assumption of growth is an important one. The world's financial systems are built on that assumption i.e. anyone who lends money expects to make a profit on the loan, after inflation if applicable. That's true of all loans, from the smallest micro-loan to the trillions in sovereign debt owed by the USA.

  • Re:No One (Score:2, Interesting)

    by HornWumpus ( 783565 ) on Tuesday August 02, 2011 @08:36PM (#36967010)

    He's not predicting the 'end of the world' he's setting up a strawman (that anybody expects exponential growth forever) then knocking it down like a high school freshman who's just discovered exponents lead to big numbers.

    Why it got on /. is another question. Lame editors feeding a blog pimp.

  • by rubycodez ( 864176 ) on Tuesday August 02, 2011 @08:40PM (#36967042)
    Soon we'll grow everything we need, we'll feed our equipment and housing rather than fuel it, let stuff grow rather than mine and refine.. Problem solved, population of ten or twelve billion humans living wealthy and prosperous lifetyles, energy needs go through the floor. As to the "Monsanto Type Personalty" problem that might arise with this, we use the time honored French Revolution solution.
  • by green1 ( 322787 ) on Tuesday August 02, 2011 @09:15PM (#36967314)

    But who is to say that increasing technology even needs increasing energy consumption?

    Every appliance today uses less electricity than the equivalent one manufactured 20-30 years ago, and some replace more than one device using less power than either one did individually. I use far less energy at home now than I did 15 years ago, and I've got more technology too, my furnace is more than twice as efficient, my insulation is significantly better, my light bulbs use about 1/3 the energy, my fridge uses less, even my stereo uses less power. The electric bill each month confirms that I'm just not using as much as I once did, despite adding 2 computers, wireless network router, network storage device, a DVD player, 2 smart phones, and various other gadgets that never even existed 15 years ago.

    There are just so many different unknowns that making any long term predictions that far out, or that all encompassing is just absurd.

  • by rsilvergun ( 571051 ) on Tuesday August 02, 2011 @09:48PM (#36967568)
    Uh, mankind has survived, but I think the point is that for all but the top 1% survival has been a brutal and unpleasant ordeal. Things like leaving your children on the side of the road to die (happening right now in Africa, as a matter of fact)...

    I see no evidence that those bad decisions have stopped. People still treat people like shit and let them breed uncontrollably. OTOH, a nice big WWIII with a few hundred million going off to die in the trenches'll solve that. Don't forget, when it comes to trench warfare it doesn't matter how smart you are. We sent Physicists off to die too.
  • by Anonymous Coward on Tuesday August 02, 2011 @10:00PM (#36967654)

    This was taken verbatim from a post from Usenet. I am not the author.

    I think we can support about five hundred billion at the levels of present day affluent American suburbia or Singaporean city:

    The more people, the more skills and human energy. But at some point we will start to run short of room on planet earth, resources, entropy sinks, and food.

    With a population of five hundred billion to one trillion, most of them living a western middle class lifestyle, we could solve the human genome problem in a few months with the money one would get by passing around your hat and free voluntary donations of time and labor. The boy scouts would have sufficient resources to build colonies on the moon and in the Kuiper belt. We would have sufficient resources not merely to map the human genome, but to understand it, and rework it, and redesign it, perhaps for purposes such as growing artificial organs and ending and reversing old age. (A project vastly larger and more difficult than merely mapping it.)

    Another area where a vast population would come in handy is the biotechnology and nanotechnology project of making useful devices that look after themselves like cats and breed like rabbits, completely absorbing the biosphere into the technosphere. Again the main obstacle to us producing such things today is the vast complexity of such things.

    The laws of physics make it impossible to move hundreds of billions of people to the stars rapidly using known or reasonably foreseeable technology, but with immortality, we would have the time and patience to travel to the stars using less rapid forms of transport. Immortality is basically a problem of understanding and reworking an immensely complicated system, thus it is a classic example the kind of scientific and technological project that would benefit from a substantially higher population.

    The question then is what are the likely physical limitations that could prevent such a desirable outcome: what would we run out of first?

    raw materials and energy:

    The cost of separating rock into its various pure chemical compounds is roughly comparable to the cost of refining ore: Therefore if we were reduced to mining rock, rather than ore that has already been separated for us by natural processes, this would increase raw materials refining costs by roughly five or ten times, since rock is roughly ten or twenty percent useful ores, depending on what one counts as useful. We are already processing low grades of iron ore which not very long ago would have been considered rock, not ore.

    Since the refining and raw material cost of ore is an insignificant fraction of total costs in an advanced industrial society, this would not have a substantial mpact. A gradual and orderly conversion to lower and lower grades of ore, until we are refining rock rather than extracting ore, will not have any large economic impact.

    A ton of granite contains uranium and thorium roughly equal to one hundred tons of coal, assuming breeder reactors and nuclear waste reprocessing. This ratio is typical of continental rocks, but is not typical of the earth has a whole: Once we strip mine the entire continental surface of the earth to about thirty or forty miles deep, we will no longer be able to employ fission power. For a population of several hundred billion immortals, people with a vastly longer perspective than ours, fission power would eventually come to be seen as disturbingly finite. Fortunately this leave more than ample time and resources to create space based solar power systems.

    For some sufficiently large population the waste heat from all this is going to cook the earth, but if we assume one trillion people consuming as much energy per head as people in the USA consume , this is not going to heat up the earth substantially.

    The total energy of sunlight falling on the earth is one hundred and ten million gigawatts. A population of one thousand billion people, consuming energy at about the rate

  • Re: I love this (Score:2, Interesting)

    by timeOday ( 582209 ) on Wednesday August 03, 2011 @01:07AM (#36968728)

    So you approve of an unfair society where people are given things that they did not earn by having it forcefully taken from someone who did earn it?

    There is no magic, infallible formula handed down from god to give the One True answer as to who "earned" what (though some answers are much more reasonable than others). NOTHING is made by an individual without building on contributions of countless other people both past and present. Not even a thought or a sentence. Thus who "earned" what equates to an argument about who deserves how much credit. Thus, for example, the inescapable complexity of property law (including all of corporate law, intellectual property law, contracts, bankruptcy, taxation) and endless arguments (lawsuits) about it.

    Pure capitalism and pure communism both lead to obviously bad solutions, so we muddle along with a messy mix of both and argue a lot about moving a little either way. But any reasonable mix is far better than either extreme.

  • Re: I love this (Score:4, Interesting)

    by ultranova ( 717540 ) on Wednesday August 03, 2011 @07:14AM (#36970300)

    So you approve of an unfair society where people are given things that they did not earn by having it forcefully taken from someone who did earn it?

    No, I think he approves the extremely fair society where people are given things that they did not earn by having them forcefully taken from someone who didn't earn it either, such as a CEO, banker, high frequency stock trader, etc. Seeing how most of the nation's wealth is currently in the hands of people who didn't earn it, there shouldn't be a shortage of things that can be justly redistributed any time soon.

    Call me crazy, but doesn't the dictionary define that sort of behavior as "theft"?

    No, thievery means taking something you don't own, not something you didn't earn.

    Also, I find it horribly ironic that you talk about the evil "greedy" people, yet you fail to see the greed in thinking you should get something that you didn't earn.

    The alternative to people getting things they didn't earn is the return to feudalism, where the local lord owns the means of production and other people obey him or die. Capitalism concentrates a larger and larger share of the wealth into fewer and fewer hands, so you either have mechanisms to redistribute it or accept that most people will get a life of miserable poverty.

Trap full -- please empty.