Easy... I'd wait until I had children and then make it so that humans could no longer reproduce.
Within 2 years abortion would have no purpose, letting the protestors shutup. Within 5 years people would have realized the importance of the children there are currently, and focus on them. In 10 years food shortages would be all but non-existant. During all this time, people would realize that the human race is coming to an end, and the humans will do their best to return the planet to the way it was before we appeared. In 18 years, there would be no underage crime, and with no more need for public schools, the governments could focus on programs that help the remaining people and restore the planet. This would continue until the very last humans looked back and contemplate the effects of the last 100 years, whether or not they did their job and fixed the planet. And then... the last human being will die, hopefully peacefully. As Nature takes the planet back, all traces of human existence will slowly disappear, even plastics, which are supposedly infinite, will be eaten by bacteria adapted to devour the abundant food source. That, to me, is the perfect end to the world.