The largest impact will be by China, India and Africa, so we'll quickly need to popularize green energy such as solar and perhaps the kinds of nuclear technology which can't be used for weapons (nuclear waste might be preferable over damages caused by pollution and climate change).
We need to be decisive and strong, which might involve bold and expensive media events and populism.
The ones who are able to think in the long term need to stop fighting themselves for superficial issues, political correctness and minor details. We need to strengthen our arguments instead and keep in mind that we are following the same ultimate goal.
Do I want to give up my car? No. What if I did want to; how would that change my outlook? I'd want cities and a job that accommodates those desires. What if everyone wanted to? Those cities would be built and politics might make cars more restricted.
There are hybrid, full electric cars out there, so if something hard to be changed, we can try to replace it with more optimal.
Going back Dark Age again will not help a lot and people will not agree to this.
While you do this the capitalists will be trying to move all the 3rd world people to the 1st world lifestyle. Just to balance things out.
Currently this always looks like, hey, X doing Y times more than I do, why I should care? This will not change anything.
Blaming China now is quite not fair, because other countries already caused this global warming, not China, they now just want to grow like the others.
This mindset of modern humans lead to lost of humanity itself. Most of the people don't care about others, they are selfish. Until every bit of climate change hit them personally (like your house underwater, boom!) then they will start to think about that and demand changes.
So "Plan B" will be waiting when this thing will blow into the face of those, but as always this will be too late.
Imagine the startup, who don't have customers yet and just gives up (because what's point, they will not come). The more traction they have, the more snowballish it become.
How regular people can help?
1) Try to use renewable materials around you (bags, not plastic bags, use the fabric)
2) Sort the garbage (don't know about US), but in Europe this is real thing (organic, general, electronics, etc)
3) Try to limit the car or any fossil fuel usage in your household.
3.1) Don't have 1 car per each family member
4) Don't buy and throw away clothes too often, if you do, return to second hand
5) Use energy saver functions at it's max
6) Stop searching for someone to blame and "Just DO IT!" (c) Shia
How IT people can help?
1) Write less energy consumption programs and servers, they eat too much now
2) Move toward real innovations in "green" tech, not the pseudo ones to collect money and bail
Samsung once done the big screen phone, how the iPhone users called them? "Shovel" phones / users. Then came this "innovative" Apple iPhone with the same big screen and it suddenly became "mainstream". Don't be afraid to be first in something good, especially if this is a future of your planet.
Don't expect that someone will make this problems "go away" or people fly away from here. Humans managed to make orbit a trash can too, so we don't go anywhere in far future.