The San Francisco Board of Supervisors has passed a unanimous measure calling for the city’s retirement system to divest over $583 million from fossil fuels. The resolution urges the $16 billion San Francisco Employees’ Retirement System to pull out the stock it holds in 91 of the 200 top fossil fuel corporations in the world. The vote marked the latest in a national effort for divestment called Go Fossil Free, which organizers say is modeled on the international solidarity campaign against South African apartheid.