The Motives of Scientists

[John McCarthy]

Jefferson Hopewell includes:

     OK, here's my shot at naming two resources that are being
     used at a rate that can neither be sustained nor replaced.

     1) Fossil Fuels
	     Coal, oil and natural gas reserves are finite and
     took millions of years to form. They will be essentially
     exhausted at some time in the near future (estimates vary).

	  2) Arable Land
	Being depleted by unsustainable agriculture practises 
	ie. Mismanaged irrigation schemes leading to salt build-up
	    Loss of topsoil (especially in semi-arid regions)
 	    Monocultures that require excessive external inputs
	    Land redevelopment
 
     Any other resources?  What about fresh water?  Where I live,
     supplies of potable water become alarmingly low recently as
     a result of increased demand due to population
     growth. Overfishing? It can take decades to recover fish
     stocks.

Hmm. I see I didn't say precisely what I meant when I used the word
"replaced".  Coal, oil and natural gas are to be replaced as sources
of energy, not replaced by more coal, oil and natural gas.  They can
be replaced by nuclear or even solar energy.

Salt-buildup is fixable by subsurface drainage.  It requires water
though.

Topsoil can be (expensively) transported from regions of surplus to
regions of scarcity.  It can also be rebuilt (expensively).  What is
this about "excessive external inputs".  To say "excessive" without
explanation is just sloganeering.  What fraction of Australian land
has been consumed by redevelopment?  I'd guess 0.01 percent.  What is
your guess?

Water for drinking is not a problem anywhere.  Water for agriculture
is the problem.  Many long term problems will correctly be ignored as
long as agricultural products are in such surplus.

We have the decades required to recover from overfishing.

There are real problems, but doing any good about them requires beng
precise.
-- 
John McCarthy, Computer Science Department, Stanford, CA 94305
*
He who refuses to do arithmetic is doomed to talk nonsense.
http://www-formal.stanford.edu/jmc/progress/