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somewhat OT, but interesting

Discussion in 'Home Power and Microgeneration' started by brian mitchell, Oct 19, 2006.

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  1. Learned today that the manufacture of portland cement, the primary
    ingredient of concrete, releases huge amounts of CO2 into the
    atmosphere. According to one site, it's the largest source of man-made
    atmospheric CO2 after transportation and electricity generation. There
    are lots of references online, just google concrete+CO2.

    I don't know all the chemistry, but cement is made by heating limestone
    to approx 2500 degrees, limestone being calcium carbonate(?) I think. So
    apparently making 1.5 tonnes of cement releases 1 tonne of CO2. Not sure
    if this includes the fuel for heating or is just the chemical change
    involved. At current rates of concrete production, that translates into
    1.8 billion tonnes of CO2 per annum, but then think of the massive
    building booms in China and other fast-developing nations.

    Something to engage the mind as you steer the gas guzzler down the
    eight-lane freeway...

    brian mitchell
  2. Eeyore

    Eeyore Guest

    Both presumably.
    Yeah well there you go !

    See my Global Cooling thread in

  3. There seem to be a number of viable --and even superior-- alternatives
    to cement as the binder for concrete, this site lists some of them

    but I bet the cement industry forms a well-muscled lobby when it comes
    to the setting of building standards.

    brian mitchell
  4. Mary Fisher

    Mary Fisher Guest

    As was always the case before power tools and transport.
    Well, probably mostly but not ALWAYS. Some of us still use our own labour
    and materials.
    I agree. I can't think of a substitute for the pc though, all of us here are
    guilty of using one and the infrastructure which supports it :-(

  5. Actually, limestone and clay. The original pozzolan cements were a natural
    volcanic ash that the portland cements mimic.

    There *is* a poartial solution.
    Magnesium cement has two desirable properties. As it 'cures' it absorbs CO2
    again, balancing the emmissions to make it, and it is much more resistant to
    salt corrosion and degradation than standard portland.

    As usual 'conservative inertia' seems to be keeping it out of sight.
  6. Alan Connor wrote:
    I think these ideas are fundamentally flawed. Human labor is
    not the most efficient or environmentally favorable method of
    getting things done and all industry is not bad.

    Gardening, for example, is a lot less efficient than farming.
    A person growing all their own food outside their back door
    would spend a lot of time and effort while a farmer could spend
    the same time and effort to grow enough food to feed thousands.

    The United States national highway system is a good example.
    When it was started they attempted to use human labor almost
    exclusively and, even though this consisted of lots of prison
    and other low cost labor, it was still too expensive and time
    consuming. It wasn't until they invented road building machines
    that the job of paving national highways was even possible.

  7. Mary Fisher

    Mary Fisher Guest

    That depends on the definition of efficient.
    But at what cost to the Earth?
    Ah - expense. In dollars, no doubt. The expense of the environment is what
    we on these groups are supposed to be considering.
    And look what happened as a result :-(

    Is it REALLY necessary to have all those leisure miles, those food miles,
    those atmosphere poisoning miles?

    Small IS beautiful.

  8. Depends on the processes used - not a simple question.

    We might also want to consider the time spent on projects, but I would
    dispute that "The expense of the environment is what we on these groups
    are supposed to be considering".

    It's certainly true that most of us seem [more] sustainable practices,
    but here on planet earth, if a project isn't financially sustainable, it
    won't go on long will it ? In short, it has to be environmentally
    better and economically viable.

    Depends what you mean by that, but I don't think all travel can be
    dismissed as a form of hedonism.

    Well sometimes.

    Cheers, J/.
  9. This seems to be a rather prejudiced way of seeing the situation.

    I'm not sure that our exploitation of a niche we discover is morally
    different from any other plant or animal that has a niche that it

    We may be more successful than some, but I'm not sure that this is a
    moral fault per se.

    And you seem to be quite keen to remove them.

    Are you concerned that the sky will fall, or do you want to bring it
    down ?

    It's funny - in all my environmental education, I've never seen that
    assumption made or implied.

    We work to improve what we have because we aren't building our
    infrastructure ab initio; we have to start from where we are !

    Well - it isn't sustainable on this scale if that's what you mean ?

    A population growth of an organism that is wired to exploit and hoard
    resources as well as do a few good things.

    Not entirely sure about that.

    And people never got miffed in the middle ages ??

    Can we borrow your rose tinted time machine please ?

    Maybe... We'll see...

    Cheers, J/.
  10. I have a lot of sympathy with the basic view that we are locked into an
    earth-destructive consumption mindset but I find your position rather
    extreme. From the very first flint axe, human beings have been
    manipulating and improving their living environment as much as they
    could; it seems to be in the nature of the beast. Your "Second Nature"
    theme is very interesting, but I think it's properly called Human
    Nature. You can take a snapshot of any period in any culture which fits
    the "pre-industrial" criterian and you'll find that it was based on a
    long history of cumulative industrial skill and investment: plant and
    animal breeding, tools and materials, transportation (ships,etc), and so
    on. So the question becomes: where do you draw the line --and *why*?

    We humans are not going to willingly go back to living conditions which
    are tougher, cruder and more uncertain than those we have now. Or not
    very far back. You might persuade someone to do without an ipod or a
    dishwasher, but not without electricity or antibiotics. So the task, I'd
    think, is to collectively come up with a set of guiding principles
    against which our actions should be measured. Sustainability (you don't
    take more than the natural systems can replace within a specified time)
    would be one obvious one but there's undoubtedly others. Within such
    guidelines, all manner of technological advance might be allowable.

    It may well be that the momentum of our appetites will propel us over
    some catastrophic cliff, but if that can be avoided I think it should
    be. You might welcome it, being Disaster Prepared, but bear in mind what
    else would be lost. All the progress in civilisation we've made --arts,
    law, health, rights and freedoms, etc-- have always been contingent on a
    necessary degree of material prosperity; you don't get one without the
    other. So I'm in favour of whatever measures can be taken to ameliorate
    the damage done. If present industry can be reformed, or diverted to the
    service of environmental sanity, I'm all for it. Better than just
    throwing up our hands and searching the attic for that flint axe-head.

    brian mitchell
  11. Cite it if you can...

    Unless he means the rural / global landscape as man has adapted
    it ?

    Sustainability ?

    Exceeding carrying capacity ?

    You don't extract resources at a greater rate that can be replenished by
    the supporting ecosystem.

    Quite so !


    Cheers, J/.
  12. Of course! I've been proposing shrinking both our population and
    our environmental footprint by shrinking the size of the average
    human being. Come to think of it, it would shrink the actual
    size of the human footprint as well.

  13. Mary Fisher

    Mary Fisher Guest

    Not guilty M'Lud.

    But it wasn't deliberate - I didn't want ANY children.
    Done that. The Fisher family ranges from 4'11" to 5'8" - he's a giant
    compared with the rest of us.
    We try our best.

  14. Toby Kelsey

    Toby Kelsey Guest

    That's incorrect and shows an ignorance of history. The deforestation of
    Europe, the agricultural failure of Tunisia (once the breadbasket of the Roman
    Empire), the denuding of Greece (noted by Plato), and the desertification of
    Mesopotamia are all examples of pre-industrial ecocide. Recent damage has
    occurred more rapidly largely because of the weight of numbers, not because of
    modern technology per se.

    Modern efforts towards sustainability have to correct over 10,000 years of bad
    habits, and some modern technologies and industries can help us do that.

  15. :) Maybe both then !

    I don't think the problem is with technology. If we only used a quarter
    of the energy and materials, I'm sure that technology, and maybe far
    more efficient technology, would still be part of the picture.

    None the less, man has had influence on the landscape, crops and animals
    for many thousands of years, and environmental and ecological impacts
    that go with them.

    Our effect didn't begin with steam power.

    Yes - that describes the industrial revolution. But he said

    "You can take a snapshot of any period in any culture which fits
    the "pre-industrial" criterian and you'll find that it was based on
    a long history of cumulative industrial skill and investment:
    plant and animal breeding, tools and materials, transportation
    (ships,etc), and so on. So the question becomes: where do you
    draw the line --and *why*?"

    Seems a fair question to me. In essence, I think he's asking at what
    point did our population and its technology become unsustainable ? Or
    to put it another way, at what point did we exceed the earths carrying

    No. One is set of techniques, the other is physical infrastructure.

    The fact that you fail to differentiate speaks volumes for your
    prejudice and wooly thinking.

    So is it your view that we were sustainable until that point ? I
    suspect that some research suggests that we may not have exceeded the
    carrying capacity until the 70s.

    Depends what you mean by progress.

    If you mean the quest for eternal economic growth I agree.

    If you mean the quest for smaller faster microelectronics I don't.

    Specifically ?

    Yes - here I think we agree.

    OK - though I'd put it another way as discussed in another post.

    Sustainability if generally held to matter at the social/societal,
    economic AND environmental levels.

    While it's true that society will collapse if the ecosystems fails, it
    will also collapse if the economy fails, or if the maintenance of social
    norms fails.

    While the ecological requirement is perhaps the most fundamental to a
    biologist, a psychologist or banker are bound to see it other ways.

    OK - personally I'd be happy to live without bankers - as long as
    there was a better alternative to banking.

    Well - no. It's not obvious, because you couldn't sensibly make those
    judgements without LCA, and even then, the interpretation is non trivial
    and 'value laden'.

    Cheers, J/.
  16. I can think of at least one other, which concerns an ethic of not
    wasting. Some resources, such as metallic ores, are not going to be
    replenished, so sustainability is not applicable. My second guideline,
    then, is: use sparingly and recycle to exhaustion.

    brian mitchell
  17. Actually, I was wondering if Alan could define at what point the natural
    impulse to improve our environment and living conditions becomes
    illegitmate. Your question, and answer, might be useful in purely
    resources vs consumption terms, but can't take account of quality of
    life issues. I think it was Abraham Lincoln who said when you can see
    the smoke from your neighbour's chimney it's time to move on.
    Yes. 'rate of replenishment' is a good concise term. Perhaps you could
    smarten up my second principle...
  18. And you are using emotive language and completely missing the
    point !

    But it hasn't failed - it has simply failed to have enough grip on
    industry. That doesn't mean that the environment movement is wrong, or
    that hiding in the woods is right.

    Well - not on a global scale anyway ! Nor has there been a reaction to
    the destruction of the environment on the scale offered by the
    environmental movement at the moment.

    Perhaps the question is, will environmentalists act to support each
    other and act collectively, or will half of them go and live in the
    hills, thereby leaving industry to do its worst ?

    It's not an "experiment" and it's not a 'rehearsal'.

    Unfortunately, THIS IS IT !

  19. Depends how broad your definition of sustainability is, though I confess
    to being more interested in the biological than the socio-economic.

    Sorry... Loosing the plot... Which was the 2nd ?

    Cheers, J/.
  20. ?

    On the other hand, the extraction of metals from their ores, and the
    subsequent manufacture of goods makes the metals available for reuse in
    highly refined form. Metals are not destroyed by use and recycling,
    though the energy inputs to the process are significant.

    The real question is

    'where are the metals now' ?

    It's about money and geographical distribution.

    See the way scrap metal prices have risen due to China sucking up raw

    Yes, though you might apply the whole 'waste hierarchy'. Most local
    authorities think there are only three Rs. Any advances on 5 ?

    (consumption/packaging etc).

    (pass on/hand down etc until worn out, then...)

    (rather than replace until BER).

    (and separate materials rather than landfilling the whole items).

    (materials to avoid refining virgin raw materials).

    A side order might be avoid the use of composite materials from which it
    is hard to recover materials for recycling.

    Another side dish is that for best results, eco design must allow goods
    to be repairable, and there must be skilled people out there to do that

    Cheers, J/.
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