Many aspects of the Californian approach to controlling the greenhouse gases that cause climate change now have a sufficient track record to provide potential models or lessons for national and even international action. In comparison, the state's efforts on climate change adaptation, although multifaceted, are less well developed and thus far have focused largely on information sharing, impact assessments, and planning. Still, adaptation could advance more quickly in California than in many other regions, given relatively high public awareness and concern, extensive scientific information, a strong tradition of local and regional planning, and some enabling policies and institutions. Much more political support and sufficient financing will have to be mustered at state and local levels to enable new projects and initiatives to cope with sea level rise, water management, and ecosystem adaptation, not to mention public health and other key areas of concern. Even so, California's initial efforts to adapt to unavoidable changes in climate may offer insights for other governments that will, inevitably, need to fashion their own adaptation strategies. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Significant efforts are underway to translate improved understanding of how climate change is altering ecosystems into practical actions for sustaining ecosystem functions and benefits. We explore this transition in California, where adaptation and mitigation are advancing relatively rapidly, through four case studies that span large spatial domains and encompass diverse ecological systems, institutions, ownerships, and policies. The case studies demonstrate the context specificity of societal efforts to adapt ecosystems to climate change and involve applications of diverse scientific tools (e.g., scenario analyses, downscaled climate projections, ecological and connectivity models) tailored to specific planning and management situations (alternative energy siting, wetland management, rangeland management, open space planning). They illustrate how existing institutional and policy frameworks provide numerous opportunities to advance adaptation related to ecosystems and suggest that progress is likely to be greatest when scientific knowledge is integrated into collective planning and when supportive policies and financing enable action.