Sierra Club v. County of San Diego

Sierra Club filed a lawsuit in California Superior Court against San Diego County charging that the County’s approvals of three residential developments did not require enforceable measures to mitigate the projects’ impacts on greenhouse gas emissions and climate as required by the California Environmental Quality Act. The petition alleged that the approval of the “three large residential development projects in the County’s rural back-country areas” would result in just under 4,000 new residential units and over 800,000 square feet of commercial office space. Sierra Club further alleged that the County allowed the projects’ impacts to be mitigated with off-site greenhouse gas emissions offsets “anywhere in the world” at the discretion of a County planning official. Sierra Club contended that allowing offsets outside San Diego County violated a mitigation measure adopted for the County’s general plan. Sierra Club also restated its challenge—previously made in separate lawsuits filed in March 2018—to the County’s Climate Action Plan, which Sierra Club alleges also did not satisfy the general plan’s mitigation requirements.