Time: Vernard Williams is about to drop some knowledge on the kids of Food and Finance High School in New York City’s Hell’s Kitchen neighborhood. He’s not facing the easiest audience. It’s a Friday afternoon in early October, the school year is still settling in, and the teenagers filing into the auditorium look less than engaged. Making things even less promising is the subject matter of today’s assembly: climate change. Williams is a senior educator for the Alliance for Climate Education (ACE), a nonprofit…