And those who must use cars could carpool more often and switch to more-efficient vehicles.

The Climate Action Plan also indicates we can reduce emissions by an estimated 328,000 tons by changing how we live at home, including better energy efficiency and waste management.

Westlund told us, "Twenty percent is not just a municipal target, it's citywide. Residences can help. Businesses can help. We're all in this together. Getting the message out is half of it."*

The grand jury report is available at www.sfgov.org/site/courts_page.asp?id=3680#reports.

Comments, ideas, and submissions for Green City, the Guardian's weekly environmental column, can be sent to news@sfbg.com.