The U.S. Gulf of Mexico Coast (hereafter referred to as “the Gulf Coast”) provides a valuable setting to study deeply connected natural and human interactions and feedbacks that have led to a complex, interconnected coastal system. The physical landscape in the region has changed significantly due to broad-scale, long-term processes such as coastal subsidence and river sediment deposition, as well as short-term episodic events such as hurricanes. Modifications from human activities, including building levees and canals and constructing buildings and roads, have left their own imprint on the natural landscape. Indeed, part of the Gulf Coast’s uniqueness is the concentration of a wide range of energy-related infrastructure in the region. This coupled natural-human coastal system and the individual aspects within it (physical, ecological, and human) are under increased pressure from accelerating environmental stressors such as sea level rise, intensifying hurricanes, and continued population increase with its accompanying coastal development. Promoting the resilience and maintaining the habitability of the Gulf Coast into the future will need improved understanding of the coupled natural-human coastal system, as well as effective sharing of this understanding in support of decision making and policies.
The National Academies of Sciences, Engineering, and Medicine’s (the National Academies’) Gulf Research Program (GRP) asked the National Academies’ Board on Earth Sciences and Resources, Ocean Studies Board, and Board on Environmental Change and Society to undertake a study on long-term coastal zone dynamics along the Gulf Coast. The ad hoc committee was asked to identify scientific and technical gaps in understanding the interactions and feedbacks between human and natural processes, to define essential components of a research and development program in response to the identified gaps, and to develop and set priorities for up to three critical areas of research. In addition, the committee was asked to identify barriers to and opportunities for more effective communication among scientists and coastal stakeholders about long-term changes to the coastal zone (see Box 1.1 for the full Statement of Task). The project originated as a way to better
understand the multiple and interconnected factors that influence long-term processes along the Gulf Coast and was envisioned to help inform decision making and research planning related to the strategic initiatives of the GRP.
In this report, the committee identifies three critical areas of research that encompass high-priority gaps in scientific knowledge that, if addressed, will increase understanding of the coupled natural-human system along the Gulf Coast. The committee also presents a research agenda that should be undertaken to meet these gaps, as well as strategies that could guide such an agenda. Finally, barriers to effective communication between scientists and stakeholders, as well as opportunities to move past these barriers, are considered.
To assist with these tasks, the committee convened three information-gathering meetings, including a workshop with 20 invited participants; heard presentations from leaders in related fields, including state and federal agencies, academia, nongovernmental organizations, and the energy industry; and consulted peer-reviewed research literature, community-sponsored efforts, and state and federal government reports from the Gulf Coast and other relevant coastal regions.
CRITICAL RESEARCH AREAS
Better understanding of long-term coastal zone dynamics involves a thorough examination of the coupled natural-human coastal system. While the interconnected and complex nature of the system makes it difficult to discuss any one aspect of the Gulf Coast region in isolation, the system can most readily be grouped into three related areas: the physical and ecological components of the natural system, the human system, and interactions and feedbacks between the natural and human systems. The Gulf Coast is governed by a combination of physical drivers originating in the ocean, in the atmosphere, and on land. These include, among others, sea level rise, subsidence, hurricane and flooding hazards, and coastal morphology. Ecosystem dynamics, structure, and function are important aspects of the ecological system. The human system includes both coastal development and adaptive responses to coastal change, such as individual and community-level decisions on targeted investment, relocation, or migration.
The committee was asked to identify up to three critical areas of research that would increase understanding of long-term natural coastal dynamics in order to advance the science and help inform stakeholder decision making. First, the committee developed a comprehensive vision that could guide the critical areas of research to understand and predict the feedbacks and interactions among the physical, ecological, and human components and the resulting evolution of the coupled system along the Gulf Coast, in the context of both human and climate drivers. Then, the committee focused on the relevant timescales for this vision: a near-decadal scale (10–50 years) and a decadal-century scale (50–200 years). These periods encompass both the timescales of the physical and ecological drivers of anticipated changes
and the motivating factors for human response and decision making. Next, the three critical areas for research were identified.
- Critical Area 1: How will coastal landforms and coastal ecosystems along the Gulf Coast respond to rapidly changing conditions (both natural and human induced), especially given the expectation for continued relative sea level rise acceleration?
- Critical Area 2: How will human settlement and economic activity along the Gulf Coast respond to evolving coastal landforms and ecosystems under rapidly changing conditions?
- Critical Area 3: How can improved understanding of both near- and long-term evolution of the Gulf Coast coupled natural-human system be applied to inform stakeholder decisions made at local, state, and regional scales? How does the coupled natural-human system evolve when decision making is updated as scientific understanding advances?
These critical areas encompass 12 gaps in the current scientific understanding of the coupled natural-human coastal system. These high-priority gaps, if addressed, will transform the present scientific understanding of the Gulf Coast coupled natural-human system and the ability to assess its future evolution. Research gaps were first identified through the consideration of one-way interactions among the various system components. They were viewed through a disciplinary lens (whether physical, ecological, or human) that could best enable progress to address each identified gap. Subsequently, the research gaps that require the consideration of feedbacks among all components of the system were discussed. It is important to note, however, that all of the research gaps (whether physical, ecological, or human) are interrelated to some degree and are intended to be thought of as integral to the Gulf Coast coupled natural-human system.
The Natural System: Physical Processes
Physical processes that drive changes in the natural coastal system occur over varying timescales that range from episodic (e.g., hurricanes, rainfall events) to longer-term processes (e.g., rising sea level, subsidence). These processes also act across a range of spatial scales and cause short-term disturbances such as flooding, shoreline erosion, and changes in water quality, as well as longer-term changes in the landscape such as wetland loss and the migration of river channels, barrier islands, and tidal inlets. Understanding key physical processes of the system, and how they interact with each other, will lead to better ecosystem management and human decision making to deal with coastal change. The following gaps
in understanding are associated with Critical Area 1 (how coastal landforms and ecosystems respond to changing conditions):
- Research Gap 1: Current datasets, monitoring systems, and approaches are insufficient to track and understand how the oceanic component of sea level (i.e., excluding subsidence) is changing along the Gulf Coast and to predict how it will change in the future.
- Research Gap 2: The causes, rates, and patterns of subsidence along the Gulf Coast are not sufficiently well understood to allow for accurate prediction at the local to regional scale.
- Research Gap 3: The combined effects of freshwater input from Gulf Coast watersheds, storm surge, sea level rise, and development on coastal flood hazards are not well understood, thereby limiting the capacity to include and model these effects in predictions of Gulf Coast dynamics.
- Research Gap 4: The relative contributions of naturally occurring and artificially managed riverine sediment delivery (e.g., availability, fluxes), diversion and management activities, and how they impact the evolution of coastal landforms (e.g., river deltas, barrier islands) and ecosystems (e.g., wetlands) is poorly understood.
- Research Gap 5: Limited understanding of sediment transport processes and uncertainties in predicting future hydrodynamic conditions hampers the ability to project long-term coastal evolution.
- Research Gap 6: There is a critical need to understand and project the future response of coastal landforms and embayments to changing climate and the conditions under which they will no longer be able to keep pace with relative sea level rise.
The Natural System: Ecological Processes
Gulf Coast ecosystems evolve continuously over decadal to centennial scales. Humans have imposed and will continue to impose substantial change from factors such as changes in the built environment, industrial activities, and climate change. Placing the ecological component within the Gulf Coast coupled natural-human system first entails understanding how ecosystems function under natural conditions, and then how human alterations affect those functions. Below are salient gaps in the understanding of ecosystem function and management under current and future conditions, also tied to Critical Area 1.
- Research Gap 7: There is limited understanding of the individual and combined effects of current environmental gradients, physical forcing, climate change,
and coastal development (including energy-related infrastructure) on Gulf Coast ecosystems.
- Research Gap 8: The understanding of strategic natural resource conservation and restoration activities for effective coastal management is limited.
The Human System
Understanding the evolution of the coupled natural-human coastal system necessitates better knowledge of the aspects of the human system that interact and feed back with the natural system. In addition, the ability to predict significant human processes with confidence over decadal to centennial timescales is poor and will be particularly challenged if thresholds of behavior, status, or perceptions are exceeded, leading to new equilibrium states for the coupled natural-human system components. The following research gaps fall within Critical Area 2 (the response and adaptation of Gulf Coast residents to changes in coastal landforms and ecosystems):
- Research Gap 9: There is a need to understand how decisions about the built environment will be affected by coastal change and how these decisions create feedbacks between the natural and human systems.
- Research Gap 10: There is a need for better understanding of how coastal changes affect the built environment and which aspects of the built environment are most vulnerable to coastal changes.
- Research Gap 11: There is an incomplete understanding of the vulnerability of different Gulf Coast communities to coastal dynamics, how coastal dynamics trigger migration and relocation decisions, and how these decisions create feedbacks to the natural system.
The Coupled Natural-Human Coastal System
Physical drivers can cause not only modifications such as coastal erosion and landform migration, but also ecological alterations such as wetland loss and displacement of biological communities. Such changes can trigger human responses that, in turn, lead to further changes in the physical and ecological systems. Human activities can also be primary drivers for change in the natural system. For instance, the impacts of human development on coastal ecosystem function or physical processes can generate feedbacks for coastal communities. The understanding of these feedbacks for the coupled natural-human system in the Gulf Coast is limited. In addition, forecasting the behavior of the coupled natural-human coastal system is challenging, particularly for longer timescales (e.g., decades to centuries). This
research gap is linked to Critical Area 3 (how improved understanding of the coupled system can inform decision making):
- Research Gap 12: Understanding how decisions about the built environment and human migration will affect the coupled natural-human coastal system is limited and can be furthered through integrated modeling.
A RESEARCH AGENDA FOR THE FUTURE
The independent, science-based National Academies’ Gulf Research Program, established in 2013 as part of legal settlements with the companies involved in the 2010 Deepwater Horizon oil spill, has grant-making capabilities that present a unique and timely opportunity for the creation of a sustained, holistic research program focused on the Gulf Coast coupled natural-human system. The Gulf Research Program could leverage its scope and autonomy to create an integrated research program that addresses critical research areas and gaps in a sustained way, as state and federal funding agencies would be challenged to support such a program due to uncertainty in their budgets from year to year. Such an effort, with coordination and integration across multiple disciplinary research streams, has the potential to positively transform living along the Gulf Coast and in coastal zones around the world. This research program can be most successful if it includes the following components:
Focus on interactions and feedbacks critical to the evolution of the coupled natural-human coastal system. While it is very useful to study specific aspects of the natural and human systems, the greatest overall benefit is likely to come from focused efforts on the processes and mechanisms that are ultimately important to interactions and feedbacks between and among the natural and human systems.
Support collaborative, multidisciplinary research teams. Many of the current gaps in understanding of the coupled natural-human coastal system are complex and are unlikely to be addressed by a single discipline; rather, collaborative research teams involving multiple disciplines across the natural and social sciences will be needed.
Encourage comprehensive, Gulf Coast-wide, integrated observational and modeling efforts. Coordinating and integrating observational and modeling efforts will significantly amplify the gains that would otherwise be achieved by observation or modeling alone. The integration of observational and modeling programs, ideally through an iterative design, facilitates the development of targeted and adaptive observational
programs, as well as the continued development of models and improvements in model skill.
Offer research opportunities that are longitudinal and multi-decadal. A program that intentionally takes the long view has the power to transform understanding of coastal evolution and to revolutionize the ability to project coastal change in the face of uncertain future conditions. Longitudinal observational, experimental, and monitoring programs can facilitate synthesis efforts aimed at tracking the drivers of change, quantifying patterns, and identifying cascading impacts through the system.
Deliver easily accessible, regularly updated observational data and model results. Making data and model results publicly available (especially in real or near-real time) and archiving them in accessible databases will extend their utility beyond scientific research and assist managers, planners, other researchers, and decision makers with adapting and responding to changing environments.
Coordinate at a high level. Management of a research and development program that includes long-term efforts that are Gulf Coast-wide and longitudinal, contains highly integrated modeling and observational components, and emphasizes interactions and feedbacks between the natural and human coastal systems needs intentional, consistent, and careful administration.
BARRIERS TO AND OPPORTUNITIES FOR EFFECTIVE COMMUNICATION
Addressing the research gaps will substantially advance understanding of the Gulf Coast coupled natural-human system and help identify salient feedbacks between humans and their environment. Turning research products into actionable policies for a more resilient future Gulf entails effective communication and collaboration between stakeholders and scientists. Specific barriers that currently prevent effective communication, as well as opportunities to overcome these barriers, are provided in the following section. In this report, “stakeholder” generally refers to a practitioner involved in coastal issues (e.g., planning or adaptation), such as a city planner or emergency manager. “Boundary organizations” play an intermediary role among different disciplines, creating and sustaining meaningful links between knowledge producers and users, and seek to provide a neutral ground for science-based discussion. A “boundary spanner” is an individual working at the edge of different groups who serves to connect those groups with each other.
Barrier 1. Financial constraints, information availability, time, and expertise represent a barrier to effective communication. These factors make it difficult for stakeholders to know about, obtain, find, work with, and interpret information and data in a way that allows them to incorporate science into decision making.
Opportunity 1. Targeted funding opportunities that would allow practitioners to obtain data and to hire staff with the expertise and dedicated time to interpret scientific information would facilitate the use and application of available scientific information by other stakeholders. Alternatively, or in addition, the development of a Gulf Coast-wide repository of scientific information managed by well-informed staff who can provide support for stakeholders would be a valuable resource that would help facilitate the incorporation of science into decision making.
Barrier 2. Many scientific products that are intended to help inform decision making are not tailored to stakeholders’ specific needs. As a result, the applicability of these products (e.g., tools, data, information) is not clear to stakeholders, who are then less likely to use them for decision making. Furthermore, many scientific products are not accompanied by sufficient instructions or training on how, why, or when to apply the provided information to the decision-making process; the information thus may go unused or may be applied inappropriately. Additionally, some products may be seen by stakeholders as serving the interests of one group over another and thus may not be seen as appropriate for decision making.
Opportunity 2. When developing products that are intended to inform decision making, scientists should be encouraged to engage substantively with stakeholders from the development to the delivery stage. Such an approach can create scientific products that are more likely to be effective and immediately applicable and may help to allay concerns over whether data are serving some needs over others. To encourage stakeholder involvement, solicitations for research programs might include a requirement for substantive and early engagement. Boundary organizations assist in facilitating this type of engagement, and including incentives for their involvement would further improve communication. The degree to which scientific information is effectively used could be further improved by streamlining and guiding the process by which stakeholders identify and access the information they need. Development of an innovative catalog of products would improve the abilities of stakeholders to access and apply these
tools in their decision-making activities. Combining this effort with staff support (see Opportunity 1) would facilitate this process.
Barrier 3. The size and complexity of the energy industry, as well as apparent limitations to information sharing, present a barrier to effective communication between the energy industry and other stakeholders.
Opportunity 3. Create an incentive structure that fosters information sharing between the energy industry and other stakeholders, as well as protocols for how to engage more effectively to facilitate information sharing. This process could be facilitated by a third party such as a boundary organization.
Barrier 4. Limited financial and human resources, logistical complexity, and difficulty in identifying all relevant stakeholders, as well as skepticism, lack of understanding, or lack of trust by one or both parties, can make it difficult for practitioner stakeholders to communicate effectively with members of the general public, including vulnerable populations.
Opportunity 4. Boundary organizations can play a key role in facilitating trusting relationships among community members, practitioners, and scientists, allowing for more effective engagement. Advisory committees comprising members of relevant stakeholder groups, including vulnerable or underserved groups, could serve as representatives for their communities and could help identify strategies for more effective communication and engagement.
Barrier 5. There can be difficulties in establishing two-way information flow between scientists and stakeholders, due to one or both parties failing to see the value of communication. Moreover, there are challenges involved in coordinating diverse entities and individuals for any particular research effort, especially when there are numerous people and groups involved.
Opportunity 5. Role-playing exercises may help ensure that scientists, stakeholders, and others see the value of two-way communication. Efforts can be made to demonstrate the effectiveness and value of community engagement through case studies and storytelling, as a first step toward further engagement. Clear lines of communication, chain of command, and protocols, as well as the involvement of boundary spanners or boundary organizations, may facilitate the coordination of stakeholders and scientists in concerted efforts and will help participants feel involved and useful and have a sense of ownership.
Barrier 6. Scientists’ engagement with stakeholders can be limited by competing demands on time and by the relative importance placed on this engagement, in terms of promotion and professional recognition. In addition, scientists are often not trained in speaking to public audiences or engaging with stakeholders. They may also not be equipped to efficiently transfer knowledge or to provide appropriately tailored information to stakeholders.
Opportunity 6. Strong relationships, collaborations, and clear communication between scientists and stakeholders help produce scientific results that are most applicable to coastal decision making. To help facilitate the development of key relationships, funding programs could provide funds for engagement and knowledge-transfer activities and consider ways to incentivize collaborations between scientists and stakeholders via boundary organizations and other boundary spanners. Notably, there is an opportunity for extension faculty associated with sea- and land-grant programs to play a prominent role in future engagement and knowledge transfer between scientists and stakeholders. There may also be opportunities to offer training for scientists on effective communication and collaboration with stakeholders. Involving university leadership in these opportunities may also increase interest in and support for scientist engagement with stakeholders.
Barrier 7. Scientists working on or wanting to engage in research relevant to the Gulf Coast but who are not from or based there may feel limited by their “outsider” status when attempting to engage with stakeholders. They may have concerns about whether their information and expertise will be dismissed, especially if the information is viewed as contrary to deeply held stakeholder views.
Opportunity 7. Funding programs that focus on Gulf Coast-related research could encourage and facilitate collaborations among regional scientists (especially those with well-established relationships with stakeholders) and those from outside the region with complementary interests and expertise. To progressively build trust and forge strong collaborations, workshops, personnel exchanges, and symposia could be used to initiate communication and discussions among Gulf Coast stakeholders, Gulf Coast-based scientists, and scientists from outside the Gulf Coast who have relevant research interests and expertise.