According to Hawking, the original aggressiveness of the people served in their favor, and gave competitive advantage in the struggle for survival — in the end the aggression persists in our genes. Now, with the rapid development of technology, the same aggression can cause our extinction as a species. To avoid this, you should suppress the instincts and anger high intelligence. And overall, the planetary government would benefit for "reconciliation" of people, addressing issues of environment and development of artificial intelligence.
However, in his opinion, there are risks — world government can acquire tyrannical nature.