[ExI] Greening the Sahara

[Henrique Moraes Machado]

--- On Fri, 7/17/09, Henrique Moraes Machado <cetico.iconoclasta at gmail.com> 
wrote:
> Dan> Any ideas on how to do this?
>> An idea I had was to cover strategic swaths of it with
>> dark material, thereby causing its daytime temperature to
>> rise causing the air to rise faster pulling in more moist
>> air from the costs. Once rainfall is higher, it seems the
>> greening would take care of itself.
>
> The Sahara is a sand desert and it´s surface is highly
> mobile. The wind blows the sand and the dunes move a lot. I
> think that any dark material covering the sand would be
> quickly covered back with sand by the blowing winds.

Dan>Yes, I mentioned just this in another email.

Sorry I didn't see it. Good to know that I'm not so far out then.

Dan>There are, however, areas of some deserts -- perhaps, including the 
Sahara; I forget at this time -- 
>where there is little sand and the surface is mostly exposed rock or 
>similar hard soil.
>This can be covered and the covering can be replaced -- as if the wind or 
>sand doesn't foil it, eventually rains will.

Kalahari in central Africa is like this.
http://en.wikipedia.org/wiki/Kalahari_Desert


> Here´s a thought. And this can be a complete nonsensical
> idea (almost certainly is). I don´t know how deep is the
> sand layer and what lies beneath, but what about digging big
> potholes (too bad we can´t use thermonuclear blasts to do
> this, because of the residual radiation) and fill them with
> seawater. These potholes evenly distributed across the
> desert could provide a lot of water for evaporation.

Dan>Well, if you're going that far, one might use space based mirrors to 
bring in more radiation.
>That might warm the surface, fueling the desired convection.
>Alternatively, one might nuke mountains to change weather patterns.
> I believe someone proposed this a long time ago for the Western US.

Yes. Go that far. If one wants to do something big, one must bring on the 
big tools.