If you are the one saying population is a problem, then you should be the one knocking yourself off - not some other guy.

I don't think population is the problem at all.

To avoid more than 2C global warming, we need to get to under 15% of 1990-level emissions by 2050.

Australia & the USA = 5% of world population, 25% of emissions

Thus, 5% of the world's population could give us catastrophic global warming all by themselves. The other 95% of the world could disappear overnight and we'd still be in trouble. The world can only sustain a population 193 million people living like Australians and Americans.

On the other hand, India has 17% of the world's population but only 4.9% of its emissions. So the world can sustain 3.5 billion people living like Indians - some very well off, some miserable, some in between like in Kerala.

Or the world could sustain about 10 billion people living like Hondurans.

Or perhaps we could sustain 9 billion or so (the most we're likely to ever see on the Earth, says the WHO and the UN) with some more ecotechnic way of life, with renewable energy and the like. We don't know, nobody's tried it. It seems worth a go.

Population: it's not how big it is, it's what you do with it.