The board of the San Francisco Employees’ Retirement System (SFERS), which manages $24 billion for its 65,000 members, last week agreed to join a movement to divest its oil and gas holdings to address climate risk in its broad portfolio.

The pension fund unanimously approved staff recommendations to create six strategies and identify the “riskiest, dirtiest” fossil fuel assets in the portfolio to begin a “prudent phased divestment of the targeted assets.”

Staff has been directed to develop the list of the riskiest investments by April and recommend a phased divestment of those securities by October. SFERS also adopted a “carbon constrained” strategy for its $1 billion passive public markets portfolio, setting a target to reduce carbon emissions by 50% compared to the Russell 1000 index.

The board approved hiring a social responsible investing director and agreed to partner with key public pension funds including the California State Teachers Retirement System (CalSTRS) and the New York City Retirement System.

SFERS also has agreed to share resources supporting collaborative initiatives to reduce the risks associated with owning fossil fuel securities, and pursue renewable and carbon-constrained investments.

SFERS President Brian Stansbury said the board is committed to “socially responsible investing,” and the pension fund “must ensure that all investment decisions meet our fiduciary duties and do not negatively affect our investment returns.

The oil, gas and coal industries have found themselves under increasing pressure from shareholders, activists and government officials to reduce carbon emissions.

Earlier this month New York City officials said they planned to end their investments in fossil fuel funds within five years. It also is seeking damages from Big Oil companies to protect the city from what it claims are the effects of climate change.