EDIT: downvoters, feel free to add your opinion, what seps we can take in 12 years to prevent climate change. I will gladly hear any opinion, especially if it is not as drastic as mine.

1. Drop coal and gas as energy sources immediately. Use renewable and nuclear energy as main power sources. Phase out nuclear after couple decades, when we hopefully can get all our energy needs from renewables. EDIT: forgot to add in fusion.

2. Eat less meat. I am not saying to go full radical vegan, just have less of it. Most people I know have meat for every main meal of the day (breakfast, lunch, dinner). We can definitely eat less of it. Meat production generates extreme amounts of CO2 and consumes too much of valuable land.

3. "Global one child policy". Sounds extreme - but we must lessen global population of humans. I know that western countries have negative growth already, problem is how to solve overpopulation in non-western countries and do it fast (ideally in one generation). Even with technological advances, IMO having 10-12+ billion people on Earth won't do any good for anyone.