The triple bottom line: bringing a sustainability framework to prioritize climate change investments for infrastructure planning

Climate change is an increasing concern of agencies, governments, and communities around the world. It poses potential adverse impacts to civil infrastructure, with consequences that include increased financial resources, economic impacts, social impacts, and planning issues. This paper aims to enhance and broaden the discussion on sustainability and the importance of the consideration of social, environmental, and technical aspects in relation to infrastructure planning. Particularly under climate change, these considerations allow for more holistic, effective, and long-term benefits to communities and economies. This paper introduces the triple bottom line (TBL) approach to sustainability as a framework for holistic infrastructure planning under the uncertainty of climate change. The economic pillar will focus on the impacts of climate change on road infrastructure and the cost–benefit of potential adaptation options; environmental considerations include quantifying the potential increase in GHG emissions from increased roadworks required by climate change damages; and the social pillar will be quantified using an index based upon the SoVI method. Each of these ‘pillars’ of sustainability will be analyzed individually and mapped using geographic information systems (GIS). Finally, a ‘holistic’ approach will be discussed, where these individual layers are combined using GIS to display the information. A case study focused on the Sacramento Region of California is used as a proof-of-concept for how the triple bottom line framework introduced here can be utilized to provide actionable, more equitable decision-making for investment in critical infrastructure adaptation policy.