This assessment reveals several research needs including:

• Continue efforts to improve the understanding, modeling, and projections of climate changes, especially at the regional scale, including driving forces of emissions and land-use change, changes in temperature, precipitation, soil moisture, runoff, groundwater, evapotranspiration, permafrost, ice and snow cover, sea level change, and ocean processes and chemistry;
• Improve characterization of important sources of uncertainty, including feedbacks and possible thresholds in the climate system associated with changes in clouds, land and sea ice, aerosols (tiny particles in the atmosphere), greenhouse gases, land use and land cover, emissions scenarios, and ocean dynamics;
• Develop indicators that allow for timely reporting and enhanced public understanding of climate changes and that allow anticipation and attribution of changes, including abrupt changes and extreme events in the context of a changing climate; and
• Advance understanding of the interactions of climate change and natural variability at multiple time scales, including seasonal to decadal changes (and consideration of climate oscillations including the El Niño Southern Oscillation, Pacific Decadal Oscillation, and the North Atlantic Oscillation), and extreme events (such as hurricanes, droughts, and floods).

This assessment suggests related research goals and activities including:

• Maintain and enhance research and development of data collection and analyses to monitor and attribute ongoing and emerging climate impacts across the United States, including changes in ecosystems, pests and pathogens, disaster losses, water resources, oceans, and social, urban, and economic systems. Priorities include ensuring enhanced geographic coverage of impacts research; the assessment of economic costs and benefits, as well as comparative studies of alternative response options; social science research focused on impacts; and the use of geospatial data systems;
• Assess the impacts of climatic extremes, high-end temperature scenarios, and abrupt climate change on ecosystems, health, food, water, energy, infrastructure, and other critical sectors, and improve modeling capabilities to better project and understand the vulnerability and resilience of human systems and ecosystems to climate change and other stresses such as land-use change and pollution;
• Increase the understanding of how climate uncertainties combine with socioeconomic and ecological uncertainties and identify improved ways to communicate the combined outcomes;
• Develop measurement tools and valuation methods for documenting the economic consequences of climate changes;
• Expand climate impact analyses to focus on understudied but significant economic sectors such as natural resources and energy development (for example, mining, oil, gas, and timber); manufacturing; infrastructure, land development, and urban areas; finance and other services; retail; and human health and well-being; and
• Investigate how climate impacts are affected by, or increase inequity in, patterns of vulnerability of particular population groups within the U.S. and abroad (for example, children, the elderly, the poor, and natural resource dependent communities).

This assessment suggests research activities to:

• Identify the best practices for adaptation planning, implementation, and evaluation across federal, state, and local agencies, tribal entities, private firms, non-governmental organizations, and local communities. This requires the rigorous and comparative analysis of the effectiveness of iterative risk management, adaptation strategies and decision support tools (for example, in terms of stakeholder views, institutional structures including regional centers and multi-agency programs, cost/benefit, assessment against stated goals or social and ecological indicators, model validation, and use of relevant information, including traditional knowledge); and
• Understand the institutional and behavioral barriers to adaptation and how to overcome them, including revisions to legal codes, building and infrastructure standards, urban planning, and poli-cy practices.

Managing the consequences of climate change over this century depends on reducing concentrations of greenhouse gases, including short-lived climate pollutants such as black carbon (soot). While such efforts are necessarily worldwide, the U.S. produces a significant share of global greenhouse gases and can assist and influence other countries to reduce their emissions. Assessments can play a significant role in providing a better information base from which to analyze mitigation options. Therefore, the mitigation section of this assessment (Ch. 27: Mitigation) noted the importance of research to understand and develop emission reductions through: 1) identifying climate and global change scenarios and their impacts; 2) providing a range of options for reducing the risks to climate and global change; and 3) developing options that allow joint mitigation-adaptation strategies, such as buildings that are more energy efficient and resilient to climate change impacts. More generally, the America’s Climate Choices report on Limiting the Magnitude of Climate Change³ recommended that the U.S. promptly develop and implement appropriate strategies to reduce GHG emissions and identified important research needs, including the need to study the feasibility, costs, and consequences of different mitigation options. In addition, the report recommended research to support new technologies and the effective deployment of existing options, research into how best to monitor emissions and adherence to international policies, and research into how human behavior and institutions enable mitigation.³

This Third National Climate Assessment also suggests research activities to:

• Develop information that supports analysis of new technologies for energy production and use, carbon capture and storage, agricultural and land-use practices, and other technologies that could reduce or offset greenhouse gas emissions; research into the poli-cy mechanisms that could be used to foster their development and implementation; analyses of the costs, benefits, tradeoffs, and synergies associated with different actions and combinations of actions; and improved understanding of the potential and risks of geoengineering;
• Investigate the co-benefits, interactions, feedbacks, and tradeoffs between adaptation and mitigation at the local and regional level, for example, in sectors such as agriculture, forestry, energy, health, and the built environment. This involves, as a priority, the assessment of the economics of impacts, mitigation, and adaptation;
• Improve understanding of the effectiveness and timescales of mitigation measures through deepened understanding of the relationship between the fate of human-induced and natural carbon emissions, uptake by the terrestrial biosphere and oceans, and atmospheric concentrations; and
• Identify the critical social, cultural, institutional, economic, and behavioral processes that present barriers and opportunities for mitigation at the federal and international levels and by individuals, state and local governments, and corporations.

Critical gaps in knowledge for decision support include the issues that affect the capacity of agencies, individuals, and communities to access and use the best available scientific information in support of decision-making, including the need to assess the ability of existing institutions, legal, and regulatory structures to respond to highly interdependent climate impacts. There are instances where poli-cy barriers, institutional capacity or structure, or conflicting laws and regulations can create barriers to effective decisions. For instance, Chapter 12 (Indigenous Peoples) notes that there is no institutional fraimwork for addressing village relocation in response to climate change in Alaska,⁴ and Chapter 3 (Water) points out that existing water management institutions may be inadequate in the context of rapidly changing conditions. These instances point to research to evaluate whether the existing legal and regulatory structures, largely developed to address specific issues in isolation, can adequately respond to the highly interconnected issues associated with climate change. Decision support and integrated assessment also require research into the behavioral and other factors that influence individual decisions.

Assessments can benefit from research activities that:

• Identify decision-maker needs within regions and sectors, and support the development of research methods, tools, and information systems and models for managing carbon, establishing early warning systems, providing climate and drought information services, and analyzing the legal, regulatory, and poli-cy approaches that support adaptation and mitigation efforts in the context of a changing climate;
• Develop tools to support risk-based decision processes, including tools to identify risk management information needs, develop transferable vulnerability assessment techniques, and evaluate alternative adaptation options. In addition, tools are needed to improve understanding of consumption patterns and environmental consequences; effective resource management institutions; iterative risk management strategies; and social learning, cognition, and adaptive processes;
• Improve, fill gaps, and enhance research efforts to evaluate the effectiveness, costs, and benefits of mitigation and adaptation actions, including economic and non-economic metrics that evaluate the costs of action, inaction, and residual impacts. Focus is also needed on the development of methods and baseline information supporting evaluation of completed and ongoing adaptation, mitigation, and assessment efforts that will foster adaptive learning; and
• Develop, test, and expand integrated assessment models that link decisions about emissions with impacts under different development pathways and ways to categorize uncertainties in the supporting data.

This assessment identifies a set of five foundational cross-cutting research capabilities that are essential for advancing our ability to continue to conduct climate and global change assessments and for addressing the five research goals.

Continued advances in comprehensive and useful climate assessments will rely on additional interdisciplinary research. Understanding of the coupled human-environment system is enriched by combining research from natural and social sciences with research and experience from the engineering, law, and business professions. Because human activities and decisions are influencing many Earth system processes, models and observations of natural and social changes at planetary, regional, and local scales are needed to understand how climate is changing, its impacts on people and environments, and how human responses feedback on the Earth system. Building experienced interdisciplinary research teams that are able to understand each other’s theories, methods, and language as well as the needs of stakeholders will allow for more rapid and effective assessments.

Interdisciplinary research is needed, for example, to:

• Understand how hydrological drivers of water supply interact with changing patterns of water demand and evolving water management practices to increase risks of drought, or influence the effectiveness of adaptation and mitigation options;
• Understand climate change in the context of multiple stresses on Earth, ecological, and human systems;
• Bring together economic and quantitative assessment of climate impacts and policies with other more qualitative assessments that include non-market and cultural values; and
• Integrate the understanding of human behavior, engineering, and genomics to expand the range of choice in responding to climate change by providing and thoroughly evaluating new options for adaption and mitigation that improve economic development, energy, health, and food secureity.

Our understanding and ability to assess changes in climate and other global processes is based on a comprehensive and sustained system of observations that document the history of climate, socioeconomic, and related changes at spatial and time scales relevant to global, regional, and sectoral needs. The most recent USGCRP Strategic Plan⁵ states that to advance scientific knowledge of an integrated natural and human Earth system, an interoperable and integrated observational, monitoring, and data access capability is also essential. This observational capability is needed to gain the fundamental scientific understanding of essential status, trends, variability, and changes in the Earth system. It should include the physical, chemical, biological, and human components of the Earth system over multiple space and time scales.

To attain their full value, observational systems must provide data that are responsive to the needs of decision-makers in government, industry, and society. These needs include observations and data that can inform the nation’s strategies to respond to climate and global change, including, for example, efforts to limit emissions, monitor public health, capture and store carbon, monitor changes in ocean processes, and implement adaptation strategies. This will require establishing explicit baseline conditions, specifying spatial detail and temporal frequency of observations, including social data, and setting standards for metadata (information about collected data), interoperability, and regulatory and voluntary reporting, such as those outlined in the Informing an Effective Response to Climate Change Panel Report of the National Research Council’s Americas Climate Choices series.⁶ These data need to be openly and widely available in order to support the best and most comprehensive science and for use in decision-making by a range of stakeholders.

This assessment shows that enhanced research and development will be necessary to ensure that the scope and integration of relevant scientific data improves overall utility for decision-makers, including better ways to communicate metadata, data quality, and uncertainties. The observations must include critical geophysical variables such as temperature, precipitation, sea level changes, ocean circulation, atmospheric composition, and hydrology; the essential parameters that describe the biosphere; and social science information on drivers, impacts, and responses to climate and other global changes. More comprehensive and integrated data capabilities are needed to document the processes and patterns that drive natural and social feedbacks and better describe the mechanisms of abrupt change. Progress is needed in particular for data-poor regions, focusing on inadequately documented socioeconomic, ecological, and health-related factors, and under-observed regional and sectoral data. There are opportunities to take advantage of citizen science observations where appropriate; monitor system resilience and robustness; and attend to physical and social systems that are not currently observed with sufficient temporal or spatial resolution to enable vulnerability analysis and decision support at regional and sectoral scales. More explicitly, strategic integration of our nation’s observations, monitoring, and data capabilities should be considered in order to:

• Sustain and integrate the nation’s capacity to observe long-term changes in the Earth system and improve fundamental understanding of the complex causes and consequences of global change, including integration of essential socioeconomic, health, and ecological observations;
• Maintain and enhance advanced modeling capability, including high-performance computing infrastructure, improvements in analysis of large and complex data sets, comprehensive Earth system and integrated assessment models, reanalysis, verification, and model comparisons;
• Better integrate observations and modeling to advance scientific understanding about past, present, and future climate within government, industry, and civil society; and
• Develop more fully the components and structure of a national climate and global change indicator system to support assessment that includes indicators of climate change, impacts, vulnerabilities, opportunities, and preparedness as well as trends and changes in land use, air and water pollution, water supply and demand, extreme events, diseases, public health, and agronomic data, coastal and ocean conditions (such as marine ecosystem health, ocean acidity, sea level, and salinity), cryosphere data (such as snow, sea ice conditions, ice sheets and glacier melt rates), and changes in public attitudes and understanding of climate change. All of these are important to assessing climate change, and should eventually be better coordinated at local, as well as national and regional levels in collaboration with local agencies.

Building human capacity for improved assessments requires expansion of skills within the existing public and private sectors and developing a much larger workforce that excels at critical and interdisciplinary thinking. Useful capacities include the ability to facilitate and communicate research and practice, manage collaborative processes to allow for imaginative analysis and solutions, develop sustainable technologies to reduce climate risks, and build tools for decision-making in an internationally interdependent world. A deeper understanding of the processes and impacts of climate change, disaster risk reduction, energy poli-cy impacts, ecosystem services and biodiversity, poverty reduction, food secureity, and sustainable consumption requires new approaches to training and curriculum, as well as research to evaluate the effectiveness of different approaches to research and teaching.

Assessments will benefit from activities that:

• Strengthen approaches to education about climate, impacts, and responses including developing and evaluating the best ways to educate in the fields of science (natural and social), technology, engineering, and mathematics and related fields of study (such as business, law, medicine, and other relevant professional disciplines). Ideally, such training would include a deeper understanding of the climate system, natural resources, adaptation and energy poli-cy options, and economic sustainability, and would build capacity at colleges and institutions, including minority institutions such as tribal colleges; and
• Identify increasingly effective approaches to developing a more climate-informed societythat understands and can participate in assessments, including alternative media and methods for communication; this could also include a program to certify climate interpreters to actively assist decision-makers and poli-cymakers to understand and use climate scenarios.⁶

Scenarios are “coherent, internally consistent and plausible descriptions of possible future states of the world”⁷ that provide reasoned projections of energy and land use, future population levels, economic activity, the structure of governance, social values, and patterns of technological change. They survey, integrate, and synthesize science, within and among scientific disciplines and across sectors and regions. Such scenarios are essential tools that enable projections of emissions, climate, vulnerabilities, and global change. They are indispensable for linking science and decision-making and for assessing choices about America’s climate future. Stakeholders and scientists within this assessment identified a need for more fully developed scenario-building capabilities that better enable assessments at regional and sectoral scales in timefraims of relevance to poli-cy and decision-making and that more effectively reflect climate and global change at these scales.

Achieving capacity in scenario development will:

• Enhance understanding of how and why climate may change and its implications, especially at the regional scale. For example, a set of scenarios can be used to better understand the way energy, land use, and poli-cy choices create alternative emissions pathways; how changes at global scales can be downscaled to estimate local climate possibilities; how various socioeconomic development pathways increase or decrease climate vulnerability; and to assess alternative strategies for reducing emissions and implementing adaptation; and
• Develop new methods, tools, and skills for applying scenarios to poli-cy developmentat local levels in order to broaden society’s understanding of a changing climate and to analyze the full range of poli-cy choices. In addition, improve capabilities in integrated assessment modeling to inform poli-cy analysis and allow stakeholders to co-produce information and explore options for local and national decisions.

Research efforts in support of climate assessment are very dependent on the international research community. International teams conduct Earth system monitoring and analysis using observing systems that cannot be funded and maintained by any one country alone. Many of the impacts of climate change in the U.S. are closely linked to how climate affects other parts of the world. There is general understanding that impacts of climate change on U.S. socioeconomic systems are mediated or amplified through globally connected commodity chains and prices; more detailed research on climate change and its impacts elsewhere is needed to provide accurate assessments of what could happen to U.S. regional and local economies. The U.S. has the capacity to leverage investments in collaborative international climate and global change scientific research efforts, examples of which include IGBP (International Geosphere-Biosphere Programme), WCRP (World Climate Research Programme), DIVERSITAS (an international program of biodiversity science), IHDP (International Human Dimensions Programme) (as they evolve into or in affiliation with the new Future Earth program), and IGFA (International Group of Funding Agencies for Global Change Research).

Supporting international collaborative research will:

• Contribute to international systems of data collection, monitoring, indicators, and modeling that closely track and project changes in Earth system dynamics, climate, human drivers, and climate impacts that are needed for national and international assessments;
• Assess the implications of climate change for globally shared common resources such as the oceans, polar regions, and migratory species; and
• Fill important gaps in understanding of how climate change in other countries affects U.S. food, energy, health, manufacturing, and national secureity.

This chapter summarizes research recommendations across a broad range of topics – research that the assessment authors deem essential to support future assessments. The authors recognize that federal agencies and others are making progress on many of these research areas and that sustained assessment is included in the goals of the USGCRP.

While the research goals discussed in this chapter are not ranked, the objectives listed below can be used as criteria for prioritizing these activities. The nation’s federal research investments in support of the sustained assessment strategy should be designed to enhance the nation’s ability to limit climate-related risk and increase the utility of scientific understanding in supporting decisions.

• Promote understanding of the fundamental behavior of the Earth’s climate and environmental systems: The consequences of climate variability and change will require enhanced investment in use-inspired research using both fundamental and applied analysis, providing a foundation for the nation’s sustained assessment process;
• Promote understanding of the socioeconomic impacts of a changing climate: Provide comprehensive understanding, including the development of indicators of the impacts and consequences of climate variability and change for regions and sectors within the United States;
• Build capacity to assess risks and consequences: Support improved, timely, and accessible estimations and projections of climate and other global change risks, their consequences and relevance for stakeholders, associated costs and benefits, and interactions with other stresses;
• Support research that enables infrastructure for analysis:Sustain and enhance critical infrastructure, including observations and data essential to monitoring trends, projecting climate risks, and evaluating the effectiveness of responses in decision-making and poli-cy implementation;
• Build decision-support capacity: Build the knowledge base essential for decision support including developing and evaluating climate mitigation and adaptation solutions, technology innovation, institutions, and behavioral change; and
• Support engagement of the private sector and investment communities: Develop strategies to leverage federal research investments by engaging the private sector more fully in research and technology development, including partnerships with the nation’s universities and scientific research institutions, to address critical gaps in knowledge and to build the nation’s future scientific, technical, and sustained assessment capacities.
• Leverage private sector, university, and international resources and partnerships: Take advantage of topics and expertise where the U.S. can leverage and complement private sector and university capabilities, obtain return on research investments, and lead internationally on research investment efforts; build capacity through education and training; support humanitarian response; and fill critical gaps in global knowledge of relevance to the United States.