Water reserves will bring violen confrontations

Water is the most valuable resource in planet earth.

Resources:

Why global water shortages pose threat of terror and war | Environment | The Guardian

Robots than could kill...

No matter how it scares you... of course is not really a god idea but... it happens.
There are a lot of machines used my army all around the world and also have weapons not only sensors.

Sources

Should a robot decide when to kill? | The Verge
X-47B | Ultimate Weapons | American Heroes Channel
Campaign to Stop Killer Robots