For example, California alone consumes about 2 million barrels of oil per day, with a population of 40 million people. Global oil production is about 90 million barrels per day. There are 1.1 billion people across the sub-Saharan Africa belt (Nigeria to Somalia). Assuming I've done the basic math right, and accounting for African oil use at present, if Africa were to consume as much oil per capita as California does, this would require an additional ~50 million barrels per day in global oil production, a greater than 50% increase.
If you can avoid waste at the refineries and the fields, less fossil fuels will have to be dig up to fulfill the same demand. Of course waste is an important issue to tackle. Sure, lowering demand or restricting supply may do more, but waste is often a relatively easy thing to tackle.
As far as tracking the big polluters, that's more misdirection. Yes, it'd be nice if oil refineries were run tightly enough that they had no local emissions, but those refined products are all going into the fuel tanks of jet planes, ships, trucks, power plants and personal vehicles, from whene they will be combusted to CO2 and injected into the atmosphere, so does it really matter where the emissions take place? This is not rocket science, just basic accounting. The end result is the same, here's a model of the yearly cycle:
https://www.youtube.com/watch?v=x1SgmFa0r04
If countries had really wanted to slow fossil-fueled global warming, they'd have started a 1% per year replacement program (renewables for fossil fuels) in the 1980s, and we'd be at a ~40% renewable ~60% fossil energy mix by now (at least). As it stands today, every single fossil fuel company and nation-state producer is looking to maintain current production levels for the next 30 years, if they can manage it. Enough with the hypocrisy and two-faced posturing at these 'global climate meetups', already.
Finally, this 'hope' business is ridiculous. The tipping point has come and gone, there are numerous global carbon models and observational data showing that even with 100% renewables tomorrow, warming will steadily continue due to permafrost melt and carbon outgassing from marine sediments. The last time CO2 levels were this high was in the Pliocene, ~2-5 million years ago, and that's where the climate is heading. Hence, human civilization will just have to adapt to these new conditions, which will be difficult and expensive and disruptive. However, since noticeable changes in climate (i.e. clearly distinguishable from the noise in the data) only appear on a ~10 year running average, this could be accomplished, with massive infrastructure projects.
However, making efforts to adapt to new conditions would require admitting that fossil fuels drive global warming, which would create more pressure to switch to renewables, and that would be resisted by entrenched economic interests... sort of a Catch-22 situation.