About the global warming post:
1) We could revert it, but we need to reduce the CO2 emissions continuously. It also seems that we would need to actively remove some of it from the atmosphere.
2) I'm not sure about our margin of time safety, but we already see some effects. Also, as I said in 1), we would need to remove CO2 from the atmosphere.
3) A major part of the extra heat and CO2 Earth is gaining actually goes to the oceans. Before we even notice right above the land, catastrophic changes are going to happen on sea ecosystems. Then the climate, because the oceans.
4) That's a more complicated issue.
It's inportant to fix the bigger, more general issues, like energy generation. We need to stop burning coal and oil. And we need stop deforestation.
We need to support the environment before (immediate) economy.
With that conscience, maybe people will adopt better choices like not using a car when they can easily walk, or ride a bike, or take the public transportation. Governments incentives on that way (more taxes on gas/cars, more subsides to bikes/buses/trains) can make the society responsibility just a natural choice instead a sacrifice! Although it's not that necessary, people need to realize they don't have to wait.
At the very least, stop wasting energy!