One of the problems with global warming is all the CO2 from cars, especially cars idling in traffic. I had a brainstorm the other day: I'm sure this will be a good idea. We should eliminate cars inside cities and use only public transit and horses. Yes, horses. OK, donkeys and mules too. Horses are generally pleasant creatures (unless ill-used), they go by themselves, they produce new horses at regular intervals with only vegetable inputs, and while they exhale carbon dioxide just as we do, they certainly don't put out as much as an idling SUV. And they use zero fossil fuels.
But they're slow, you say. Um, so is most city traffic. Would we really go that much more slowly on or behind a horse than we do in a traffic jam now? Look at how the bicycles whizz past you when you're stuck. Besides, we move too fast these days. Going more slowly would be good for us. We could still use cars on the freeway for long distances, where they get better mileage. I freely admit horses aren't so good for long distance travel.
What about the road apples? People welcomed cars as a solution to pollution in the last century because cars don't poop in the street. There's the brilliant idea. The streets were full of horse poop in the 19th century because it was waste; nobody could think of a use for it except fertilizer, and farmers had their own supply. Some farms are now taking their manure dumps and processing them to extract methane which they burn for heat and power. With today's technology, it could conceivably be profitable to pay for recycled horse manure to feed into a power generation plant. Once people know they will be paid for it, they'll pick it up; look at what they do with cans and bottles. Homes could have their own small co-generation plants, for the local horse's poop; it's another way to go off the grid.
Energy independence through horse manure! It's the wave of the future.