David Hoag

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What do you think the carrying capacity of the Earth is?

I recently read it is a popular belief amongst scientists that the Earth's carrying capacity is between 9 and 10 billion people.
If there is any truth to the idiom 'Necessity is the mother of invention', I'd wager quite a bit higher. Considering some of the factors used to make this estimate (access to freshwater, amount of arable land, etc.), I feel the number should be much higher. Invention and innovation will create more efficient things. I mean, the oceans alone offer a great deal. Growing up, not out. Changing food sources to synthetic varieties could certainly cause one to recalculate the carrying capacity.

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    Oct 14 2011: BTW I recently spotted this conversation from Hans Rosling (of the amazing animated stats talks) in which he argues (convincingly to me, at least) that the end is in sight for population growth: http://www.ted.com/conversations/39/why_do_so_many_think_that_popu.html
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    Oct 15 2011: From what I've read about E.O. Wilson's theories and Mr. Rosling's ideas, I agree. The evidence they've gathered/analyzed suggests they're right. I was merely wondering how many people COULD live on the Earth under the impression that current and future innovations alter the criteria by which the experts have chosen 9 to 10 billion (increase in birth rate, fecundity, urban expansion, building technology, energy sources, genetic science, agricultural science). I suppose, the sky's the limit, but even that isn't true.
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    Oct 14 2011: Not having read your report, it would be hard for me to comment on it, but I think you're right in one regard. Urban sprawl is a significant phenomenon. Calgary, Canada is a good example. Lots of houses. Not many apartments. Seoul, South Korea (where I live now) is closer to being the opposite. Apartments as far as the eye can see.
    Perhaps, if 'spilling...into the farmland' is something we wish to avoid, then building more 50 floor apartments with greenhouses on the roof, or building underground will become attractive options. I might even guess that we will put our diets under greater and greater scrutiny thus decreasing waste food, abolishing wasteful agricultural practices (cattle, etc.), and genetically modifying food to contain more of what we need (for example, a rainbow potato with a variety of phyto/cyto chemicals and oozing with a range of vitamins and minerals). Living in smaller spaces (no more 100 acre private estates, or even apartments greater than 800 sq.ft.), recovering lost surface area by recycling our waste entirely (I think this is possible).
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    Oct 14 2011: This could be a question with a scary answer. I read n article in Time magazine that the carrying capacity was around 21 Billion. For what it's worth I did a 2 page report on the problems of population growth and the carrying capacity of the world for World cultures class.I theorized that people would end up spilling out of cities and moving into areas of farmland. You may think "so what, a couple of acres lost isn't THAT big of a deal".Your right, it isn't.But if 10 million people do this to 20 million acres of farmland, than there won't be a sufficiant amount of food for the world.People would then move to places that had food in it. Then those places would got over populated,then THAT farmland would be gone. Until eventually there is nowhere left to grow food, and everyone dies. Kind of eeri but true
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      Oct 14 2011: yeah, nice idea, except the current trend is for people to move into cities, not out of them. time magazine's number is tabloid quality. nothing supports that number, but it can sell some more copies for them.
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        Oct 14 2011: at the time, people will move into cities.But when the populations double or triple. Places of high population will not quite as great to live in. And even though its the trend, there are still some people moving to rural areas
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    Oct 14 2011: in my opinion, with adequate technology, it is beyond a trillion.
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      Oct 14 2011: Adequate technology certainly is an enabler. Water purification advancements. Success with fusion (crosses fingers), engineering and architectural innovations to increase resistance of collapse from earthquakes paired with societal acceptance of living in gargantuan buildings (tall like the Burj Dubai only cube-shaped) and virtual reality growing so ubiquitous it becomes a new age problem.
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    Oct 14 2011: I've read that the Earth can carry another 1500 billion tons, if the weight is equally distributed. If you're average human is 50 kg, that makes 30 000 billion people?
    Right?