[LMB] [OT] May I do this?

[James Nicoll]

On Wed, 20 Dec 2006, I wrote:

> At 10:19 PM 19/12/2006, M Traber wrote:
>
>> Heavy population.
>> 
>> I see a "green" world - very stringent controls on emissions of various 
>> sorts [air, water, particulates, solid waste] heavy reliance on recycling. 
>> Instead of petroleum products or stopgap electric hybrids we might frex see 
>> main reliance on biodiesel [http://www.biodieselhomekit.com/]
>> If we can whip the air pollution aspect of infernal combustion, or improve 
>> it to where the particulates are almost nonexistant.
> Water recycling: water is a MAJOR problem in Australia, which is approaching 
> population limits already, and also in Africa. The increases here would 
> strain Europe heavily, with most of the rest stressed. This problem may be 
> exacerbated by deforestation.
>
 	I'm sure everyone will be happy to know that if this world uses 
only desalinated water and even if none of the water they draw from the 
oceans ever gets back (which seems quite unlikely, to understate it) and 
if their per capita water use is the same as North America's, they only
draw down the oceans by 1/100,000th per year.

 	I was checking to make sure they don't need to worry about 
increasing the ocean's salinity because that has climate implications. The 
more saline the seas are, the smaller the Artic seas ice build up is and 
the lower the Earth's albedo. Our current cycle of ice ages may owe 
something to the fact that a lot of salt is locked away at the bottom
of the Med.

 	Of course, if we think up a better way to turning sunlight into 
food, we can cut back on water use (and our ecological footprint) by quite 
a lot. As I recall, about 40% of the land surface of Earth is devoted to 
agriculture in one form or another but since humans only require 100 Watts
to run and since about 340 W reach each square meter of the Earth, it is 
clear that this is a very lossy way of making food. If we thought up some 
method that only turned 10% of sunlight into chemical bonds that we can 
use, we could feed all 6.5 B of us off a patch of ground 140 km on an 
edge. This would be somewhat less than 40% of the land surface of Earth.

 	The fraction of the land mass not used for cities (and at typical 
urban densities, you can fit 36 billion people onto a patch a bit smaller 
than Canada) could be encouraged to host complex ecosystems, if not 
necessarily the ones that were there in the first place. I have great 
hopes for a parrot-derived predator filling the rough niche of a smart 
terror-bird. I think eco-tourists would love them.