>but if this is the only solution, why not?
It's not the only solution, and government didn't create it. People are causing global warming, not government. It's people who decide to use cars and get stuck in traffic instead taking a bus, bus will go that route anyway, people in cars will cause more traffic and generate more pollution.
People who don't turn off lights (also TVs, computers) at their homes over night. I met a lot of them, one of the dumbest excuse was... light bulbs break if we turn on and off the lights frequently, so they were leaving 3x 100W lightbulbs overnight, irony, they were working as council of Greenest Capital of Europe :)))
People who burn coal and wood to heat homes, burn coal = more CO2, burn wood = less forests.
People who don't recycle stuff - I'll just throw away that TV on a street or drop from 2nd flow window for fun! Ha! People who buy new phones and computers because that's a new fashion.
People who eat food that was grown in places were 10years ago we could see amazon rainforests.
People are too lazy and it's too hard for masses to leave their comfort zones.