Marine & Coastal Adaptation Challenges

Climate change poses significant challenges to marine and coastal resources and communities. Adaptation refers to efforts to avoid, minimize, and recover from the effects of climate change, including activities to reduce harmful impacts (e.g., inundation of coastal infrastructure) and/or take advantage of potential opportunities (e.g., longer growing seasons).

Over the last decade, significant progress has been made in the earlier phases of adaptation (e.g., building awareness, conducting assessments, planning potential strategies) while the actual implementation and evaluation of adaptation measures and projects has advanced more moderately. Adaptation progress in marine and coastal systems has been hindered by a number of factors. How these factors challenge on-the-ground decision-making is not uniform across all geographies and sectors (e.g., physical characteristics of some coastal areas may prevent landward retreat of wetlands), however, it is useful to identify the ways in which practitioners are limited by barriers.

Common barriers noted in our interviews and surveys included:

  • Lack of funding or budgetary constraints
  • Lack of institutional mandates to take adaptation action and/or insufficient staff capacity to respond
  • Lack of political will from government agencies to encourage and enforce implementation
  • Lack of stakeholder awareness, support, and engagement as a result of inertia, skepticism, and/or other priorities

Technical barriers include limitations in the availability and applicability of adaptation options for implementation; for example, what can be done and with what resources (e.g., availability of and access to information, internal staff capacity, and technical expertise, assistance, or knowledge). For example, the unique and complex hydrological and ecological nature of the Mississippi River Delta has complicated efforts to address storm surge flooding in New Orleans. During Hurricane Katrina, storm surge overtopped levees and was funneled through the Mississippi River Gulf Outlet, causing 15-feet deep floodwaters in local neighborhoods. The Lake Borgne Surge Barrier was constructed to limit saltwater inundation while a complementary pumping system helps to minimize freshwater flooding in the city.1 These and other infrastructure elements (e.g., roads, flood control structures) have reduced the supply of sediment to the area, causing coastal lands in Louisiana to subside and making the area more vulnerable to sea level rise.

Financial barriers to adaptation include the near- and long-term costs as well as the availability and flexibility of funding sources. In general, significant upfront capital investment is needed for infrastructure-based adaptation solutions (e.g., seawalls, storm surge barriers, saltwater intrusion barriers), which are associated with high maintenance costs and typically require continual reinvestment (Azevedo de Almeida & Mostafavi 2016; Bertule et al. 2018). Nature-based approaches, such as coastal wetlands, coral and oyster reefs, and green infrastructure, have been noted to be more cost-effective in terms of upfront and maintenance costs (Bertule et al. 2018; Reguero et al. 2018). Federal government assistance programs are available to support recovery from climate-related disasters, but tend to disproportionately favor wealthy individuals and communities (Howell & Elliott 2019). For example, several Native Alaskan coastal villages are in critical need of relocation due to thawing permafrost and increased storm surge exposure. Some of these villages, such as Newtok, Kivalina, and Shishmaref, have actively pursued relocation to different sites for over 20 years, but due to estimated costs ranging from $80–400 million, these efforts have been put on hold in favor of short-term shoreline protection measures. To date, Shishmaref has spent over $25 million on measures such as seawalls.2

Social or cultural barriers to adaptation may arise from conflicting interests of stakeholders and/or sectors (e.g., public vs. private landowners, public resistance, disproportionate effects on vulnerable groups). This category also includes cognitive barriers to risk perception and willingness to change individual and collective behaviors to address climate change. Some adaptation approaches may exacerbate existing inequities, leading to the displacement and forced relocation of individuals and communities, especially those already subject to a legacy of discriminatory practices. Community input and engagement early on in the adaptation planning process is critical to match adaptation actions to specific community needs (Azevedo de Almeida & Mostafavi 2016). For example, the City of Virginia Beach leveraged a number of tools to engage residents and other coastal stakeholders (e.g., developers) in the development of their Sea Level Wise strategy.3 The city conducted public listening sessions, convening residents to better understand local-level issues with respect to flooding. During these sessions, the city gathered residents’ pictures of flooding events and cross-referenced with sea level rise projections as a means to validate models.

Governance barriers include the presence and flexibility of regulations and policies, and clarity on who is responsible for on-the-ground implementation in a particular area. Decision-making in a changing climate is also challenged by uncertainty in terms of which adaptation strategies are best suited for different conditions (Eriksen et al. 2011), variable planning horizons for near- (e.g., El Niño events, king tides) and long-term (e.g., sea level rise) stressors (Ju et al. 2019), and other competing or different priorities in coastal communities (e.g., availability of affordable housing and rising property values) (Gibbs 2016; Gregg & Braddock 2020). Some existing policies and regulations are not conducive to accommodating climate adaptation measures (e.g., the federal Stafford Disaster Relief and Emergency Assistance Act provides funds in response to, rather than in advance of, disasters [Perls 2020] and does not include slow-onset events such as sea level rise, drought, and erosion [Horn et al. 2021]). In many cases, adaptation has been hindered by the extent to which individuals communities and agencies can implement strategies on their own parcels of land. For example, the Boston Water and Sewer Commission (BWSC) is an independent entity that provides water and sewer services to the City of Boston, but does not own the land where existing utility structures are sited and where new structures may be needed to better address climate change. New structures such as dams as well as wastewater systems updates may be needed on privately-owned lands. While BWSC is working closely with the city and local partners that also share a sense of urgency to address sea level rise, how and where new infrastructure can and will be built remains unclear.4