Second Joke: Remember Independance Day , the film where Aliens blow up the white house? And are stopped by a basic computer virus? They're frikken OSS utopianists! With laser beams!
Although the rising levels of acidity and CO2 in oceans is benefiting CO2->O2 and acidity absorbing bacteria and algae, so we might want to block out the sun over land in specific places. The Sahara, or Australian outback seem like good ideas (CHEAP arable land! WOO!) Australia has the advantage of being close to the worlds population center, so an extra breadbasket would be fantastic.
Of course the world's energy problems (mirrored solar, is gooood), food problems (recycling, and composting, more arable land... we really did urbanize the best farm land), and transportation problems will be improved as we like each other more and urbanize more densely and closer together (what is with the pressure differentials in condominiums, why is no one ever blasting rock music on their balcony [guess I'm young], and the dry air from the air vent!). Two of these seem to be happening a bit. It's hard to imagine a world where all three have happened so much that we want to scale them back, and I suppose that makes them good things.
Sadly people who walk and read are generally intelligent and busy (looking for extra information, instead of overwhelmed by it at least) and to loose a few during their learning period probably isn't great for society as a whole. Considering how few people do this it's amazing that they're even talking about it.
It is a scary notion that this is replicating.
Actually I used to run everywhere until I was about 8, enjoyed the exercise + hey more videogames! I only stopped because of social pressure, which is sad. Running gives people more time in their lives rather than spending less time at the Gym