Oil prices and birdsong
Markie and I spent a few days at her friends' farm in Raymond, Washington. They have 152 acres of timber (it would have been 160 except for the road) so it's extremely quiet; just the birds, the wind in the leaves and the sound four people and a dog make while reading on the porch.
I don't think we realize how we've destroyed birdsong with our urban development. Silence, sure, we all want more peace and quiet, but when you get out here you're overwhelmed by the birdsong. I had forgotten how much it was part of walking at the Sea Ranch when I was growing up (there are white crown sparrows here, I haven't seen any, but I remember their call).
All the cars growl in a low roar in the city. It's amazing how it drones even at 4 am, after the drunks have passed out but before the early risers have headed to the gym.
If we do actually transition from internal combustion to electric vehicles, we may get some of that birdsong back. Cities are getting more forested as they mature, so the canopy is back, even if the meadows aren't.
Of course there will be leaf blowers, exhaust fans, and booming music. Heck the amount of noise that four adults makes isn't negligible. Chit chat, clanking of pots and pans, yelling at the dog... Multiply that by a million people in a greater metro area and there's still a low roar.
But maybe it will be a roar that doesn't carry as far and we'll be able to hear the birds again in the city...