You didn't write anything with which I disagree.
However, there simply are not enough resources on the planet for 1-2 billion more people to run up their energy and then find efficienies later. If you don't want to talk about climate chage than how about fresh water, trees, and fish.
The reality is that there is a net loss of forests, the majority of our fisheries are at capacity or in decline, etc. etc.
I am not a "sky is falling" moonbat. I consistently advocate market/technology based solutions. But the scale of the problem and size of the investment needed, combined with pricing in of previously externatilized costs requires policy. Smart policy.
Can you explain how that is "liberal thinking"?
Liberal thinking is pretending that economic growth and prosperity can be created through central planning. If there is a little central planning (e.g. basic air quality protection), that is not going to necessarily lead to liberalism although even that bureaucracy will inevitably get crazy (e.g. formulas for gas that make people drive 20 miles extra to get it cheaper). The real liberal thinking comes from planning how people live, e.g. public transportation, mixed with promotion of politically favored projects like farm subsidies.
I didn't directly answer your question about the third world. My main answer is free trade to bring up their living standards. Our wealthy manufacturing work force has taken the brunt of this, while poor manufacturing workers have had a rapid increase in living standards. Wealth also seems to bring down birth rates.