Re: The Great Wall of Oz
I think the value here is how easily it gets us all talking about something as important as climate change and our responsibility to the environment. When we talk about things like the Dutbowl (perfect example, Dave, and you made me want to watch that documentary), that really tugs at a core human issue we can't avoid - what do we owe back to the planet that gives us so much, will we ever fully understand it, and what our the consquences if we mess up? For some of these issues, it will not affect us, but instead, our children -what about our responsibility to them? Is technology or progress always the answer? A giant wall won't answer that question, but at least it will get us talking about it.
As for the wall itself, I'll agree that it's more sky than pie of an idea. Maybe it would work, scientifically, but the cost-benefit ends up awful sketchy any way you slice it. About offsetting the cost by putting people, vertical farming, etc. in it? It all seems very speculative - none of us are qualified to to talk about any of that, and as we've seen many times, often the 'experts' aren't either. As for the general notion that we should spend less money on war and more on humanitarian efforts? Here here, you won't find me disagreeing. Maybe it's not that simple, but I think in the year 2014 our priorities could do with a little re-evaluating at the least.