Water: it poses one challenge after the next in the 21st Century. It’s increasingly scarce, it’s increasingly dangerous as sea levels rise, and it’s increasingly changing the workforce.

But one of its most vital functions is often overlooked: the fact that it’s a lynchpin for (relative) world peace. Without clear distinctions of who it belongs to and how to share it, the world would be thrown into chaos.

Earlier this year as part of our Grand Challenges series, we reached out to a panel of water experts to describe the big problems we’re facing when it comes to the precious commodity. What they said was clear: “hydro-politics” – politics surrounding the availability and accessibility to water – will shape the 21st Century.

Take an example: the Nile flows through myriad countries, starting in Ethiopia and ending in Egypt. That gives Ethiopia an upper hand in geopolitics, because if tensions prompted it, it could theoretically cut off or limit that huge water supply to Egypt.