McKibben joins Sanders’ other four appointments: scholar and racial justice activist Cornel West; Native American activist Deborah Parker; Minnesota Congressmember Keith Ellison, who chairs the Congressional Progressive Caucus; and Palestinian rights activist and scholar James Zogby, who founded the Arab American Institute.

We speak with 350.org co-founder Bill McKibben about how he’ll seek to translate his activism into Democratic Party platforms in Philadelphia in July.