I wonder how these alternatives affect things in the future when they are done on such a massive scale they can actually replace fossil fuels. Enormous wind farms will have immediate effects on weather, possibly farther spread than you would think. Pretty much all energy on the face of the planet comes from the sun, which also affects weather patterns - wind, rain, everything - so what happens when mass areas are covered with solar panels. What's the environmental impact of altering ocean currents in an attempt to generate energy from them? Even fusion... what's the impact of pumping massive amounts of sea water through these systems? Wouldn't that eventually affect something? It seems like we can't win if we keep demanding more energy. At least the air will be cleaner, though.