[lovemenot]

Large human population is an issue. But if you accept that as a premise, Megacities are more efficient in terms of resource usage than equally-sized but geographically dispersed populations.

As for water usage, think first of agriculture, then industry. Only after that do cities come into play. Cities are relatively small water consumers.

[throwaway0a5e]

A city may be more efficient than lower population density on a per-capita basis but that is only tangential to the problem. A city in the California desert is not a good reason someone in NYC should have to endure a washing machine and dishwasher that are so stingy about water usage they are frequently ineffective at their primary task.

>As for water usage, think first of agriculture, then industry. Only after that do cities come into play. Cities are relatively small water consumers.

Where do those agricultural products get sold and eaten?

<insert screeching about "taxing muh negative externalities" here>

[bluGill]

See my other post: agriculture water is not heated or treated. Thus cities use as much energy for their water despite only using a fraction. In all of the above water itself is not the issue as it isn't lost, just moved downstream until the water cycle (rain - which has always been non-uniform) brings it back.

[ashtonkem]

Typically even within residential areas the issues isn't people per se, it's lawns and golf courses. And those are absolutely not evenly distributed or used.