The western world may be built on oil, but without water we'd all be dead within a week – it's our most vital resource.

One in nine people globally still don't have running water, and with efforts to counteract global warming at times piecemeal and always contentious, managing the world's water supply is likely to become more of an issue for all of us.

The good news is that technology is being developed that will soon enable us to dramatically, exponentially, increase our water efficiency – but you might not like the sound of it. We're talking about toilets that recycle water from human waste. That's right: poop.

Reinventing the t