It is my belief that the ones actually most qualified to be world leaders are the ones that do not want the job.
For those that believe in a planet first philosophy ... What is best for the planet may not be what is best for human kind. If humans truly cared about the condition of the planet they would live like the American Indian did years ago, or maybe like the Amish. The problem with this is innovation comes to a halt and we would not survive the next mass extinction event. Also, I know from direct experience, that most people that push a people last agenda tend to be the ones least likely to survive when the going gets tough. The human race thrives on conflict and competition in all its forms. It is what has taken us from living in caves to walking on the moon. The only way we would ever put aside all our differences would be to function like a mindless collective and every attempt at that type of social experiment has failed miserably. Technology is also a double edged sword. We need it if we are going to ever get off this rock but becoming reliant on it and allowing it to be used for the few to control the many is very dangerous.
I believe in balance. Too hard a swing in one direction always results in a equally hard correction to the other side. Study history in actual books. You are going to find that something sounding good does not necessarily make it so.