Michael Tobis wrote:
> 10 billion has the disadvantage that it is worse than 9 billion, but
> it has the advantage that it is close enough for these sorts of
> calculations and makes the arithmetic easier! I'd like something more
> precise than "too many", but an error of less than 11.11% seems close
> enough for a first cut.
>
> The solar power driving the weather and the ocean circulation is still
> about 4 orders of magnitude larger than human energy usage. Let's
> stipulate that the current energy consumption of the average American
> can be scaled up by 25; let's stipulate fusion power for instance if
> you can't bring yourself to believe in that much wind and solar.
>
> The thing I am wondering is what we will be eating. For one thing, I
> understand that natural gas is involved in bulk in obtaining nitrogen
> fertilizer. What are the impacts of the gas running out? This is a
> chemical process and I believe that alternative energy supplies don't
> figure into it directly.
I don't think that is correct. Natural gas is currently used as a
convenient source of hydrogen, but this could in principle be replaced
by electrolysis of water - it is really energy that is needed, not
specific chemicals (nitrogen gas is also common enough). (We do mine for
potash which is also needed as a fertiliser, and I don't know what
alternatives there are.)
Of course we can make copious amounts of fresh water too, given enough
energy. And crop yields could easily be raised massively in many regions
of the world given unlimited water, fertiliser and (mechanical) labour.
So really it seems that it all can be boiled down to energy if one is
prepared to assume that sustainable energy supplies can grow hugely (and
at a low price). I wouldn't like to guess whether there is currently
enough farmland to feed everyone to USA standards were it all farmed
with modern methods and high inputs, but that would certainly produce a
whole lot more food than we have at present.
> This is nothing new of course, but I wonder if it is ethical to
> consume at the current average American rate (never mind much higher
> rates common among the wealthy)? People have asked this question many
> times before, and more than a few have answered in the negative. I'm
> reserving judgment even on that yes/no question. I'd like to see the
> arithmetic either way. In the end this is not a binary question. The
> sustainable mean impact is a quantitative question and an important
> one. It should be answered in a quantitative way.
Well, if you take "ethical" as synonymous with sustainable, and use your
previous definition of sustainable, then the answer is clearly no for
the present and foreseeable future. I don't think any detailed sums are
required for that. If you want to talk about ultimate physical and
biological limitations then the answer will be yes if you are prepared
to assume enough miraculous technology. I suppose we can talk about how
much miraculous technology would be required...it seems to me that the
most immediate issue is energy, and this is also pretty fundamental to
other aspects of the problem.
James
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