Summary
Climate change is affecting the health and well-being of Americans across all parts of the country. Coastal areas are enduring more frequent and severe flooding due to sea level rise and storm surge; western states and Alaska have had increasingly devastating wildfires driven in part by hotter, drier, and longer fire seasons; and communities across the nation have suffered through extreme precipitation events and heat waves. These and other climate changes are posing risks to society—to people, their property, and their way of life—and to ecosystems, from croplands to national parks. In response to observed impacts and greater understanding of projected future challenges and opportunities, decision makers at local to national scales are considering how to reduce and manage societal risks associated with climate and other global changes in the coming decades by implementing a combination of mitigation and adaptation actions.
For more than three decades, the U.S. Global Change Research Program (USGCRP or “Program”) has coordinated global change research across parts of the federal government. USGCRP, an interagency program established by Congress under the Global Change Research Act (GCRA) in 1990, consists of 13 federal agencies and departments and is overseen by the National Science and Technology Council. Fostered by USGCRP, interagency partnerships and collaborations with experts across the nation and the world have led to an unprecedented effort to observe, understand, predict, and project changes in natural and built environments.
In the fall of 2015, the National Academies of Sciences, Engineering, and Medicine’s Committee to Advise the U.S. Global Change Research Program was asked to produce a report on the accomplishments of USGCRP over its first 25 years of existence. The committee highlighted four high-level examples of accomplishments in the report (NASEM, 2017a): supporting global observations systems; advancing Earth system modeling; increasing understanding of carbon-cycle science; and making progress toward the integration of the human dimensions of global change. The 2017 report also articulated the value-added of USGCRP research and coordination activities and the important evolution in their strategic planning to serve the needs of the nation.
The Program has continued to coordinate global change research activities across parts of the federal government, including establishing new interagency working groups on the water cycle and on understanding the dynamics of coastal systems. The
most significant public accomplishment during the past 5 years was the release of the Fourth National Climate Assessment (NCA4) in 2017–2018.1 The NCA4 provided many key updates on the state of the science and impacts of global change.
As mandated in the GCRA, the Program prepares decadal strategic plans laying out goals and priorities for federal research to advance scientific understanding and communicate information useful for policy decisions. The National Academies Committee to Advise the U.S. Global Change Research Program is charged to review the Program’s draft strategic plans and to provide guidance to the Program on an ongoing basis. The committee prepared this report to inform USGCRP’s thinking as it develops the next decadal plan, due to be completed in 2022.
Specifically, in preparing this report, the committee was tasked to consider how USGCRP can best meet the mandate2 of the GCRA for the coming decade, in light of the significant climate change impacts happening today and the increases in their magnitudes and changes in their patterns that are projected over this time period, within the context of the longer-term changes projected in our climate and environment. This report identifies critical climate change risks, research needed to support decision making relevant to these risks, and opportunities for USGCRP’s participating agencies and other partners to advance these research priorities (see Appendix A for the full Statement of Task).
The committee strongly supports ongoing efforts to observe, model, analyze, and communicate the physics and biogeochemistry of the climate system and the many mandated and other activities of USGCRP including conducting assessments. The committee assumes these efforts and activities will continue in the coming years.
In this report, the committee focuses on key risks the country could face in the 2030s, and highlights research needs that, if addressed, might increase resilience while supporting other societal goals, particularly the goal of reducing inequities. The committee has centered its advice in this report on how USGCRP could evolve to approach global change research differently in the coming decades, stressing that the largest risks expected will likely arise from the interactions of multiple systems, such as the food-energy-water nexus in the context of a changing climate. In addition, the report stresses that effective responses will arise from integration of social and natural sciences.
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1 NCA4 Part I, the Climate Science Special Report (CSSR), was released in 2017, and NCA4 Part II, the full assessment report that included the summary of the CSSR, was released in late 2018.
2 To develop and coordinate “a comprehensive and integrated United States research program which will assist the Nation and the world to understand, assess, predict, and respond to human-induced and natural processes of global change.” Section 101(b). Public Law 101-606(11/16/90) 104 Stat. 3096-3104.
This report does not provide a comprehensive list of global change research priorities, nor does it specify exactly how the Program should achieve the proposed evolution. The committee recognizes that USGCRP agencies and leadership are best positioned to identify how to accomplish this progression within the complex interagency environment, as proven by the Program’s flexibility since its founding to evolve to meet the needs of the nation.
CLIMATE CHANGE POSES SIGNIFICANT RISKS TO AMERICAN SECURITY
Climate change currently poses risks to the American people, with projections indicating that each additional unit of warming will further increase these risks for nearly all impacts investigated. In this report, the term “risk” is used as defined by the Intergovernmental Panel on Climate Change (IPCC): “the potential for adverse consequences for human or ecological systems, recognizing the diversity of values and objectives associated with such systems”3 (IPCC, 2019b, p. 696). Examples of risks in this report include those to health, food, water, energy, and transportation systems, and risks that affect the economy and national security. New research is needed to understand and communicate complex interactions among climate change (including uncertainties), other global changes such as disruption of the global nitrogen cycle, and societal development. Of special interest is the extent to which these interactions create immediate and urgent risks to Americans over the next decade, individually and collectively. Crucially, new research is needed on strategies to effectively and efficiently manage and reduce these risks in decades to come.
USGCRP is well positioned to help marshal the resources across multiple participating federal agencies, as well as other partners (e.g., state, local, and tribal policy makers), to support decision makers as they address these risks. Indeed, the Program has already taken steps in this direction, including past efforts to frame sections within the National Climate Assessments in terms of risk. That said, the committee believes that USGCRP and its participating agencies should make a significant pivot and center their next decadal plan, and the resulting priorities and activities, using an integrated risk-framing approach—that is, one that considers the risks to human and natural systems posed by climate change, and when appropriate, climate change together with other global changes. The committee also recommends focusing on and communicat-
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3IPCC (2019b, p. 696) continues as follows: “Relevant adverse consequences include those on lives, livelihoods, health and well-being, economic, social and cultural assets and investments, infrastructure, services (including ecosystem services), ecosystems and species. In the context of climate change impacts, risks result from dynamic interactions between climate-related hazards with the exposure and vulnerability of the affected human or ecological system to the hazards.”
ing the vulnerabilities and capacities of exposed systems and how these could shift over time, taking into account the multiple interconnections of projected changes, responses, and effects in human and natural systems. This approach is critical to effectively providing the information needed by decision makers at local to national scales.
INTEGRATED SYSTEMS-BASED RESEARCH IS CRITICAL FOR MANAGEMENT OF CLIMATE RISKS
Decision makers in many levels of government, in private sector firms, and in society are increasingly requesting information on risks and responses to help them design and implement risk-reduction strategies. Traditional climate research that projects changes in the natural environment and then estimates the potential consequences of these changes for human systems, typically within sectors, is not fully meeting decision-maker needs. These projections rarely consider the complex multidirectional interactions among natural and human systems.
In this report, the term “natural systems” refers to the physical climate system and ecosystems (both unmanaged and managed, such as croplands), whose dynamics are governed by biological and/or physical processes. “Human systems” refers to systems managed by people to meet specific needs of society, and whose dynamics are governed by human actions. This report focuses on a set of human systems that evolved to meet specific societal needs: health, food, water, energy, transportation and infrastructure, the economy, and national security. These human systems interact with each other and with the physical climate system and ecosystems in complex ways through a series of drivers and feedback loops (see Figure S.1). The security of these human systems depends on their complex interdependencies, as well as interactions with natural systems. The management of risks to the coupled human-natural systems to increase their security for the benefit of society and the environment requires advances in scientific understanding of climate, ecosystem, and social and behavioral sciences.
The committee identified seven critical human systems at particular risk from global change (discussed in detail in Chapter 2). “Systems” in this context refers to the individual human and natural systems, as well as the multidirectional coupling of human and natural systems; risks to these systems are the focus of Chapter 2. Effectively managing risks through mitigation and adaptation (focus of Chapter 4) would increase the security of these systems. Figure S.2 describes key terms used throughout the report.
Given its mandate to coordinate research across multiple agencies and the multiple dimensions of global change, USGCRP should play an important role in accelerating integrated, systems-based research. This research will be most efficient when coordinated with comparable international research and data collection efforts.
The Program has generated new insights since the last decadal plan (notably the sector-based assessments on food security [Brown et al., 2015] and impacts of climate change on human health [USGCRP, 2016]). However, meeting the urgent decision needs of the next decade will require increased commitment to research efforts that take a systems approach, involve collaborations among experts from across the health,
social, engineering, and natural sciences, and more explicitly consider the interactions among natural and human systems. Engagement with a range of stakeholders from local to national scales throughout the process will improve the usefulness and usability of insights generated.
The USGCRP mandate includes global environmental changes other than climate change; however, the primary focus of this document is on those risks posed by climate change. That said, the risk framing advocated here can be also applied to other global change issues and their interactions with social systems and climate change.
Driven by the urgency of addressing climate impacts happening today and projected risks for the near future, an integrated systems-based risk-management approach will enable USGCRP to more fully meet the mandate of the GCRA. This approach is the logical extension of the research priorities described in the Act and reflects the progression of knowledge and the advancement of data and research tools. Advances in fundamental and applied Earth system science over the next decade will be significantly more useful and usable by increased integration of natural and social sciences, improving the balance among physical climate research, ecosystems research, and human systems research.
New Research on Mitigation and Adaptation
Today, as climate consequences are clearly seen across the nation and the globe, there is an urgent need for policies to manage risks. New research is required to identify, communicate, and evaluate risk-management decisions covering the full range of potential policies that promote mitigation and adaptation strategies across local, national, and international scales. During the next decade, USGCRP will be increasingly called on to coordinate, rapidly advance, and communicate research in these areas, and to collaborate with global efforts.
Reducing Risks by Reductions in Global Greenhouse Gas Emissions and Lowering Their Atmospheric Concentration.
Achieving net-zero emissions4 of carbon dioxide from human activities is critical to managing climate change risks because this approach will inherently lower all future risks through avoided or captured emissions. Pursuing and informing mitigation-related policies will require better understanding of: (1) emissions targets that will avoid the most severe risks of climate change; (2) thresholds and tipping points in the climate system; (3) the socioeconomic risks of climate change, including thresholds and tipping points in social systems; (4) approaches for CO2 removal, reliable sequestration, and utilization; (5) approaches to motivate effective uptake of policies and technologies; and (6) the ability to accurately quantify, and independently verify, the emissions of greenhouse gases (GHGs) at national and global scales. It is important to recognize that the strategies to reduce emissions and lower atmospheric concentrations also pose a range of associated risks to human-natural systems.
Increasing Resilience to Reduce Climate Change Risks to Americans.
As stated in the GCRA, adaptation is an essential partner of mitigation in society’s responses to global changes. Research on adaptation is critical for developing effective policies to manage the consequences of change. Effective policies at local to national scales require increased emphasis on access to, and effective uptake of, projected changes in climate and socioeconomic systems to inform decision support. Research and coordination
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4 Net-zero emissions are achieved when any CO2 or other greenhouse gas emitted is offset by an equivalent amount of CO2 removal and sequestration (NASEM, 2021a).
are needed to better understand: (1) the efficacy of adaptation practices implemented at local, state, federal, and tribal scales, and applied by industry and other actors; (2) what additional efforts are needed, today and in the future; (3) current and projected economic and social consequences of policy choices; (4) the processes of decision making to manage synergies and trade-offs over multiple scales; and (5) synergies and trade-offs between different adaptation and mitigation options.
In order to inform effective decision making that utilizes these strategies to reduce risk, increased understanding is needed not only on mitigation and adaptation options but also on the synergies and trade-offs between options. Additionally, decision makers might need to consider other strategies to reduce risk, such as solar geoengineering; advancing understanding to inform such decisions would likewise benefit from a highly integrated research strategy.
CROSSCUTTING ANALYSES AND DATA ARE NEEDED TO SUPPORT MANAGEMENT OF CLIMATE RISKS
USGCRP has a long history of providing high-level coordination and communication of the research conducted at federal agencies through participating members in the Subcommittee on Global Change Research and interagency working groups established around priority focus areas for the Program. Given its role, mandate, and accomplishments in this coordination, USGCRP is especially well suited to make progress on additional crosscutting research efforts. These efforts would facilitate cross-comparison, provide consideration of the intersections of impacts (and responses) across multiple systems, and eliminate redundancy in underlying analyses.
An integrated, systems-based approach—that is, one that considers the multidirectional interactions among the physical climate system, ecosystems, and human systems—would benefit from the pursuit of several crosscutting priorities that can provide for the examination of challenges within and across the integrated systems. The report identifies five crosscutting areas that will contribute to addressing climate
change risks: (1) extremes, thresholds, and tipping points; (2) simulation of regional- and local-scale climate; (3) a scenarios-based approach to project and manage climate change and associated risks; (4) equity and social justice; and (5) augmentation of existing analysis frameworks and supporting data.
Extremes, Thresholds, and Tipping Points.
Extreme weather-related events have a range of societal impacts such as those associated with heatwaves, floods, storms, and wildfires. Research needs remain in projecting the frequency and severity of these events and improving attribution that links extreme events to natural and human-caused climate change. Of relevance to this research are the impacts of extreme events and tipping points on current and projected implications for a range of issues including asset values, human migration, conflict, and political instability.
Simulation of Regional- and Local-Scale Climate.
Tools that provide the starting point for understanding of future climate—global climate models or Earth system models—have limited ability to simulate local-scale climate. However, societal harms from climate change very often occur on the local scale—for example, a low-lying area is flooded, or a town is destroyed by wildfire. There is an urgent need to improve capabilities to simulate local-scale climate, including hazards not represented, or not represented well, in global climate models such as coastal storm surge and wind intensity and direction driving wildfires. In addition, it is essential that these local-scale projections be presented in a manner that is useful and accessible to decision makers to increase resilience in their communities.
Refining a Scenarios-Based Approach to Project Climate Change, Associated Risks, and Effectiveness of Mitigation and Adaptation Policies at Global to Local Scales.
Because managing climate change is an adaptive risk-management activity, it is important to project risks under a range of future climate and socioeconomic scenarios. Scenarios can be developed at local to global geographic scales and for decisions that will be taken at short to long timescales. Scenarios can be primarily model-based or can use models in participatory processes that include relevant communities to develop narratives and quantifications tailored to local decision-making needs. By championing state-of-the-art scenario-based models and processes that combine knowledge from across scientific disciplines and include a variety of relevant actors such as local stakeholders, USGCRP can help decision makers and others envision the risks associated with alternative combinations of GHG emissions and possible development pathways; these represent important uncertainties that need to be understood, quantified, communicated, and managed.
Equity and Social Justice.
Climate change risk issues should be considered from the perspective of equity and social justice. Important issues include how extreme events
and tipping points are and will be experienced differently across social groups, how mitigation and adaptation strategies have differential effects and might alleviate or exacerbate inequities, and how an equity and justice framing may increase the effectiveness of integrated risk management. The committee urges USGCRP to be attentive to multiple dimensions of equity and social justice, including race, ethnicity, indigenous status, gender identity, income and class, disability, age, and religion.
Augmenting Existing Analysis Frameworks and Supporting Data.
Progress in research on global change risks, as well as the crosscutting topics, requires implementation of augmented analysis frameworks that can more adequately represent interactions among the physical climate system, ecosystems, and human systems. Enhanced data sets are needed to more adequately represent the many system interactions and provide results in forms that meet the needs of decision makers and the people they represent. More generally, there is a need for supporting and using advances in 21st century technologies, including big data management and related analytical technologies such as artificial intelligence, agent-based modeling (where appropriate), and emerging visualization approaches, as well as well-established approaches that are facilitated by emerging methods and technologies.
SHIFTING THE USGCRP PARADIGM TO SUPPORT MANAGEMENT OF CLIMATE RISKS
The global crisis of the COVID-19 pandemic, its accompanying economic disruptions, and, in the United States, growing concerns with racial justice, inequality, and polarized politics demonstrate the need to envision and plan for multiple, often simultaneous, and multilevel disruptions to human systems, as well as to physical and ecological systems. Such preparation for multiple cascading risks requires interdisciplinary science more than ever, including the full range of disciplines across natural and social sciences. The ability for the nation to understand, adapt to, and respond to global changes will require investment from the U.S. research enterprise commensurate with the daunting challenges posed by the impacts of climate change on these interacting systems.
The committee recommends the Program employ an integrated systems-based approach to risk management:
- The systems on which the approach is based are coupled human-natural systems.
- The core focus of the committee’s recommendations is managing risks of a changing climate to these systems, which are essential life-support systems for society.
- Management options for these risks include mitigation and adaptation and strategies that combine them.
- This risk-management approach should be comprehensive and integrated—considering benefits, trade-offs, path dependencies, and interactions among the risk-management components, their attendant uncertainties, and the interplay between and across the identified system. This needs to be done within a flexible framework that fosters the integration of the human and natural system components and the dynamic changes they will undergo through time.
This integrated systems-based approach is essential for understanding and communicating the complex consequences of concurrent mitigation and adaptation actions and their interaction. A comprehensive risk-management perspective will facilitate how the Program addresses emerging challenges posed by global change, including the co-benefits of mitigation actions and the synergistic and/or antagonistic results of multiple adaptation strategies, in ways that will be useful to and taken up by decision makers at multiple levels of society.
Meeting this ambitious update to its mandate will require a significant paradigm shift for USGCRP. Federal agencies that are already part of USGCRP will need to intensify their engagement in the Program, increasing involvement of suborganizations that bring relevant expertise and operational responsibilities to the table. It will also require greater participation of federal mission agencies that historically have not participated in USGCRP (e.g., U.S. Department of Homeland Security and its components such as the Federal Emergency Management Agency) but have relevant resources and expertise. In addition, it is critical that the next strategic plan outline the process through which participating agencies coordinate and adjust their individual program plans to avoid duplication and fill gaps critical to meeting overall program objectives. The committee recommends that the strategic plan should make clear the management structure and program criteria for setting priorities, sequencing investments, and guiding development of an integrated program across the individual agencies. This
process should include input from user communities on a sustained basis consistent with effective engagement practices. This sustained engagement will require broader participation of user communities in the Program’s planning and research that will effectively expand the coproduction approach already adopted by some USGCRP entities and will help identify research priorities based on the value of the information generated. This expansion of the next strategic research plan demands a rethinking of how the Program is organized and structured.
Engaging local to national stakeholders throughout the cycle of setting research priorities is a core concept of this report. These stakeholders will assist in identifying effective implementation options and evaluating the degree to which evolving capacities will enhance the value of information generated. Throughout the process, special efforts are needed to counter inequitable distribution of risks, benefits, and costs across social groups.
Expansion of USGCRP would benefit from an analysis that considers a variety of approaches to growing the global change research enterprise to meet the evolving and intensifying challenges of global changes to society. Approaches to be explored in this analysis include: the reallocation of existing resources within the federal agencies and departments that make up USGCRP today; the inclusion of relevant federal agencies and departments not formally engaged with USGCRP; when warranted and possible, the acquisition of additional federal funds to support new research initiatives; and the fostering of public-private partnerships to expand the intellectual and financial resources supporting critical global change research.
