Sediments, ice, corals, and trees are just some of the natural storehouses of information that help tell the complicated history of Earth?s climate. Paleoclimate researchers use these ?proxies,? in combination with numerical models, to gain understanding of the magnitudes, rates, and drivers of past climate variability with the goal of informing understanding of current and future change in Earth?s climate system. The Paleo Perspectives on Climate Change (P2C2) program of the National Science Foundation (NSF) has advanced paleoclimate research through proxy development, data-model comparisons, and synthesis work, and has facilitated interdisciplinary collaboration that has contributed to the growth of the field. This new publication highlights discussions at a June 2021 workshop that focused on identifying potential future paleoclimate research directions to further advance understanding of past climate and better inform the public and decision makers about the expected future. Table of Contents Front Matter Overview Introduction Understanding Past Climate Forcings and Sensitivity Glacial, Ocean, and Land Processes and Feedbacks Resolving Regional Climate Change: Advancing and Synthesizing Knowledge How the Paleoclimate Community Can Better Engage on BAJEDI Issues Closing Thoughts References Appendix A: Statement of Task Appendix B: Biographical Sketches of Planning Committee Members Appendix C: Workshop Agenda

The United States' tradition of conserving fish, wildlife, habitats, and cultural resources dates to the mid-19th century. States have long sought to manage fish and wildlife species within their borders, whereas many early federal conservation efforts focused on setting aside specific places as parks, sanctuaries, or reserves. With advances in landscape ecology over the past quarter-century, conservation planners, scientists, and practitioners began to stress the importance of conservation efforts at the scale of landscapes and seascapes. These larger areas were thought to harbor relatively large numbers of species that are likely to maintain population viability and sustain ecological processes and natural disturbance regimes - often considered critical factors in conserving biodiversity. By focusing conservation efforts at the level of whole ecosystems and landscape, practitioners can better attempt to conserve the vast majority of species in a particular ecosystem. Successfully addressing the large-scale, interlinked problems associated with landscape degradation will necessitate a planning process that bridges different scientific disciplines and across sectors, as well as an understanding of complexity, uncertainty, and the local context of conservation work. The landscape approach aims to develop shared conservation priorities across jurisdictions and across many resources to create a single, collaborative conservation effort that can meet stakeholder needs. Conservation of habitats, species, ecosystem services, and cultural resources in the face of multiple stressors requires governance structures that can bridge the geographic and jurisdictional boundaries of the complex socio-ecological systems in which landscape-level conservation occurs. The Landscape Conservation Cooperatives (LCC) Network was established to complement and add value to the many ongoing state, tribal, federal, and nongovernmental efforts to address the challenge of conserving species, habitats, ecosystem services, and cultural resources in the face of large-scale and long-term threats, including climate change. A Review of the Landscape Conservation Cooperatives evaluates the purpose, goals, and scientific merits of the LCC program within the context of similar programs, and whether the program has resulted in measurable improvements in the health of fish, wildlife, and their habitats. Table of Contents Front Matter Summary 1 Introduction 2 Scientific and Conservation Merits of Landscape-Scale Conservation and the Landscape Conservation Cooperatives 3 Evaluating the Landscape Conservation Cooperatives Network Strategic Plan 4 An Examination of the Evaluation Process for the Landscape Conservation Cooperatives 5 The Landscape Conservation Cooperatives and Other Similar Federal Programs 6 An Assessment of the Early Accomplishments and Likely Long-Term Outcomes and Impacts of the Landscape Conservation Cooperatives Network References Appendix A: Greater Sage-Grouse: A Collaborative Conservation Effort Appendix B: Mississippi River Basin and Gulf Hypoxia: Collaborations Across Multiple LCCs Appendix C: Guidance for Landscape Conservation Planning and Designs Appendix D: Description of Other Federal Programs Appendix E: Secretarial Order No. 3289 Appendix F: Landscape Conservation Cooperatives 2014 Network Strategic Plan Appendix G: Goals of Individual LCCs Compared to Goals of the LCC Network Strategic Plan Appendix H: Committee and Staff Biographies

Climate is changing, forced out of the range of the past million years by levels of carbon dioxide and other greenhouse gases not seen in the Earth's atmosphere for a very, very long time. Lacking action by the world's nations, it is clear that the planet will be warmer, sea level will rise, and patterns of rainfall will change. But the future is also partly uncertain-there is considerable uncertainty about how we will arrive at that different climate. Will the changes be gradual, allowing natural systems and societal infrastructure to adjust in a timely fashion? Or will some of the changes be more abrupt, crossing some threshold or "tipping point" to change so fast that the time between when a problem is recognized and when action is required shrinks to the point where orderly adaptation is not possible? Abrupt Impacts of Climate Change is an updated look at the issue of abrupt climate change and its potential impacts. This study differs from previous treatments of abrupt changes by focusing on abrupt climate changes and also abrupt climate impacts that have the potential to severely affect the physical climate system, natural systems, or human systems, often affecting multiple interconnected areas of concern. The primary timescale of concern is years to decades. A key characteristic of these changes is that they can come faster than expected, planned, or budgeted for, forcing more reactive, rather than proactive, modes of behavior. Abrupt Impacts of Climate Change summarizes the state of our knowledge about potential abrupt changes and abrupt climate impacts and categorizes changes that are already occurring, have a high probability of occurrence, or are unlikely to occur. Because of the substantial risks to society and nature posed by abrupt changes, this report recommends the development of an Abrupt Change Early Warning System that would allow for the prediction and possible mitigation of such changes before their societal impacts are severe. Identifying key vulnerabilities can help guide efforts to increase resiliency and avoid large damages from abrupt change in the climate system, or in abrupt impacts of gradual changes in the climate system, and facilitate more informed decisions on the proper balance between mitigation and adaptation. Although there is still much to learn about abrupt climate change and abrupt climate impacts, to willfully ignore the threat of abrupt change could lead to more costs, loss of life, suffering, and environmental degradation. Abrupt Impacts of Climate Change makes the case that the time is here to be serious about the threat of tipping points so as to better anticipate and prepare ourselves for the inevitable surprises. Table of Contents Front Matter Summary 1 Introduction 2 Abrupt Changes of Primary Concern 3 Areas of Concern for Humans from Abrupt Changes 4 The Way Forward References Appendix A: Biographical Sketches of Committee Members

More intense heat waves, extended wildfire seasons and other escalating impacts of climate change have made it more important than ever to fill knowledge gaps that improve society's understanding, assessment, and response to global change. The US Global Change Research Program (USGCRP) - a collection of 13 Federal entities charged by law to help the United States and the world fill those knowledge gaps - laid out proposed mechanisms and priorities for global change research over the next decade in its draft Decadal Strategic Plan 2022-2031. The draft plan recognizes that priority knowledge gaps have shifted over the past decade as demand has grown for more useful and more inclusive data to inform decision-making, and as the focus on resilience and sustainability has increased. As part of its work in advising the USGCRP since 2011, the National Academies reviewed USGCRP's draft plan to determine how it might be enhanced. Advances in the draft plan include an increased emphasis on social sciences, community engagement with marginalized groups, and promotion of diversity, equity, inclusion, and justice in the production of science. Strengthening the interconnections between the plan's core pillars and expanding opportunities for coordination among federal agencies tasked with responding to global climate change would improve the plan. The draft plan could more strongly convey a sense of urgency throughout the plan and would benefit from additional examples of key research outputs that could advance policy and decision making on global change challenges. Table of Contents Front Matter Summary 1 Introduction and Background 2 Cross-Cutting Themes and Issues to Strengthen the Draft Decadal Strategic Plan for 2022-2031 3 The Four Pillars References Appendix A: Statement of Task for the Committee to Advise the U.S. Global Change Research Program Appendix B: USGCRP Transmission Memo Appendix C: Committee Member Biographical Sketches Appendix D: Line-by-Line Comments

The Earth system - the atmospheric, hydrologic, geologic, and biologic cycles that circulate energy, water, nutrients, and other trace substances - is a large, complex, multiscale system in space and time that involves human and natural system interactions. Machine learning (ML) and artificial intelligence (AI) offer opportunities to understand and predict this system. Researchers are actively exploring ways to use ML/AI approaches to advance scientific discovery, speed computation, and link scientific communities. To address the challenges and opportunities around using ML/AI to advance Earth system science, the National Academies convened a workshop in February 2022 that brought together Earth system experts, ML/AI researchers, social and behavioral scientists, ethicists, and decision makers to discuss approaches to improving understanding, analysis, modeling, and prediction. Participants also explored educational pathways, responsible and ethical use of these technologies, and opportunities to foster partnerships and knowledge exchange. This publication summarizes the workshop discussions and themes that emerged throughout the meeting. Table of Contents Front Matter Overview Introduction Emerging Approaches for Using, Interpreting, and Integrating ML/AI for Earth System Science Challenges and Risks of Using ML/AI for Earth System Science Identifying Future Opportunities to Accelerate Progress Closing Thoughts References Appendix A: Statement of Task Appendix B: Planning Committee Biographies Appendix C: Workshop Agenda

Emissions of carbon dioxide from the burning of fossil fuels have ushered in a new epoch where human activities will largely determine the evolution of Earth's climate. Because carbon dioxide in the atmosphere is long lived, it can effectively lock the Earth and future generations into a range of impacts, some of which could become very severe. Emissions reductions decisions made today matter in determining impacts experienced not just over the next few decades, but in the coming centuries and millennia. According to Climate Stabilization Targets: Emissions, Concentrations, and Impacts Over Decades to Millennia, important policy decisions can be informed by recent advances in climate science that quantify the relationships between increases in carbon dioxide and global warming, related climate changes, and resulting impacts, such as changes in streamflow, wildfires, crop productivity, extreme hot summers, and sea level rise. One way to inform these choices is to consider the projected climate changes and impacts that would occur if greenhouse gases in the atmosphere were stabilized at a particular concentration level. The book quantifies the outcomes of different stabilization targets for greenhouse gas concentrations using analyses and information drawn from the scientific literature. Although it does not recommend or justify any particular stabilization target, it does provide important scientific insights about the relationships among emissions, greenhouse gas concentrations, temperatures, and impacts. Climate Stabilization Targets emphasizes the importance of 21st century choices regarding long-term climate stabilization. It is a useful resource for scientists, educators and policy makers, among others. Table of Contents Front Matter Section I Synopsis Summary Overview of Climate Changes and Illustrative Impacts Section II 1 Introduction 2 Emissions, Concentrations, and Related Factors 3 Global Mean Temperature Responses 4 Physical Climate Change in the 21st Century 5 Impacts in the Next Few Decades and Coming Centuries 6 Beyond the Next Few Centuries References Appendix A: Statement of Task Appendix B: Committee Membership Appendix C: Methods Appendix D: Acronym List

The US Global Change Research Program (USGCRP) is a collection of 13 Federal entities charged by law to assist the United States and the world to understand, assess, predict, and respond to human-induced and natural processes of global change. Global Change Research Needs and Opportunities for 2022-2031 advises the USGCRP on how best to meet its mandate in light of climate change impacts happening today and projected into the future. This report identifies critical climate change risks, research needed to support decision-making relevant to managing these risks, and opportunities for the USGCRP's participating agencies and other partners to advance these research priorities over the next decade. Table of Contents Front Matter Summary 1 Introduction 2 Global Change Risks to Human Systems 3 Integrated Systems-Based Research 4 Research on Approaches Critical to Managing Climate Risk 5 Crosscutting Research and Data Priorities 6 Next Steps for Shifting the USGCRP Paradigm References Appendix A: Statement of Task Appendix B: Committee Member Biographies

Climate change is creating impacts that are widespread and severe for individuals, communities, economies, and ecosystems around the world. While efforts to reduce emissions and adapt to climate impacts are the first line of defense, researchers are exploring other options to reduce warming. Solar geoengineering strategies are designed to cool Earth either by adding small reflective particles to the upper atmosphere, by increasing reflective cloud cover in the lower atmosphere, or by thinning high-altitude clouds that can absorb heat. While such strategies have the potential to reduce global temperatures, they could also introduce an array of unknown or negative consequences. This report concludes that a strategic investment in research is needed to enhance policymakers' understanding of climate response options. The United States should develop a transdisciplinary research program, in collaboration with other nations, to advance understanding of solar geoengineering's technical feasibility and effectiveness, possible impacts on society and the environment, and social dimensions such as public perceptions, political and economic dynamics, and ethical and equity considerations. The program should operate under robust research governance that includes such elements as a research code of conduct, a public registry for research, permitting systems for outdoor experiments, guidance on intellectual property, and inclusive public and stakeholder engagement processes. Table of Contents Front Matter Summary 1 Introduction 2 Assessment of the Current Solar Geoengineering Research and Research Governance Landscape 3 The Decision Space: Context and Key Considerations for Solar Geoengineering Research and Research Governance 4 A Solar Geoengineering Research Program: Goals and Approach 5 Solar Geoengineering Research Governance 6 An Integrated Agenda for Solar Geoengineering Research References Appendix A: Statement of Task Appendix B: Speakers from the Committee Meetings & Webinars Appendix C: Scenarios Developed By the Committee for the "Decision Maker Needs" Webinars Appendix D: Biographical Sketches of the Committee Members Appendix E: Acronyms and Abbreviations

The drylands region shared by the United States and Mexico currently faces multiple sustainability challenges at the intersection of the human and natural systems. Warming and drying conditions threaten surface water and groundwater availability, disrupt land- and marine-based livelihood systems, and challenge the sustainability of human settlements. These biophysical challenges are exacerbated by a highly mobile and dynamic population, volatile economic and policy conditions, increased exposure to extreme events, and urbanization on marginal, vulnerable lands. The U.S. National Academies of Sciences, Engineering, and Medicine collaborated with the Mexican Academy of Sciences, Academy of Engineering, and the National Academy of Medicine to plan a 2-day binational workshop, Advancing Sustainability of U.S.-Mexico Transboundary Drylands. The workshop goals were to highlight the challenges facing the region, assess the scientific and technical capacity that each nation can bring to bear in addressing these challenges, and identify new opportunities for binational research collaboration and coordinated management approaches in the advancement of sustainability science and development. This publication summarizes the presentations and discussions from the workshop. Table of Contents Front Matter 1 Introduction and Background 2 Understanding the Transboundary Drylands Region 3 Four Key Topics 4 Innovations and Solutions in Sustainability Science for Drylands Areas 5 Key Themes and Possible Next Step Appendix A Agenda Appendix B Participants Appendix C Biographical Sketches of Steering Committee Members and Presenters

For nearly a century, scientific advances have fueled progress in U.S. agriculture to enable American producers to deliver safe and abundant food domestically and provide a trade surplus in bulk and high-value agricultural commodities and foods. Today, the U.S. food and agricultural enterprise faces formidable challenges that will test its long-term sustainability, competitiveness, and resilience. On its current path, future productivity in the U.S. agricultural system is likely to come with trade-offs. The success of agriculture is tied to natural systems, and these systems are showing signs of stress, even more so with the change in climate. More than a third of the food produced is unconsumed, an unacceptable loss of food and nutrients at a time of heightened global food demand. Increased food animal production to meet greater demand will generate more greenhouse gas emissions and excess animal waste. The U.S. food supply is generally secure, but is not immune to the costly and deadly shocks of continuing outbreaks of food-borne illness or to the constant threat of pests and pathogens to crops, livestock, and poultry. U.S. farmers and producers are at the front lines and will need more tools to manage the pressures they face. Science Breakthroughs to Advance Food and Agricultural Research by 2030 identifies innovative, emerging scientific advances for making the U.S. food and agricultural system more efficient, resilient, and sustainable. This report explores the availability of relatively new scientific developments across all disciplines that could accelerate progress toward these goals. It identifies the most promising scientific breakthroughs that could have the greatest positive impact on food and agriculture, and that are possible to achieve in the next decade (by 2030). Table of Contents Front Matter Summary 1 Introduction 2 Crops 3 Animal Agriculture 4 Food Science and Technology 5 Soils 6 Water-Use Efficiency and Productivity 7 Data Science 8 A Systems Approach 9 Strategy for 2030 Appendix A: Biographical Sketches of Committee Members Appendix B: Open Session Meeting Agendas Appendix C: IdeaBuzz Submissions Synopsis and Contributors

To achieve goals for climate and economic growth, "negative emissions technologies" (NETs) that remove and sequester carbon dioxide from the air will need to play a significant role in mitigating climate change. Unlike carbon capture and storage technologies that remove carbon dioxide emissions directly from large point sources such as coal power plants, NETs remove carbon dioxide directly from the atmosphere or enhance natural carbon sinks. Storing the carbon dioxide from NETs has the same impact on the atmosphere and climate as simultaneously preventing an equal amount of carbon dioxide from being emitted. Recent analyses found that deploying NETs may be less expensive and less disruptive than reducing some emissions, such as a substantial portion of agricultural and land-use emissions and some transportation emissions. In 2015, the National Academies published Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration, which described and initially assessed NETs and sequestration technologies. This report acknowledged the relative paucity of research on NETs and recommended development of a research agenda that covers all aspects of NETs from fundamental science to full-scale deployment. To address this need, Negative Emissions Technologies and Reliable Sequestration: A Research Agenda assesses the benefits, risks, and "sustainable scale potential" for NETs and sequestration. This report also defines the essential components of a research and development program, including its estimated costs and potential impact. Table of Contents Front Matter Summary 1 Introduction 2 Coastal Blue Carbon 3 Terrestrial Carbon Removal and Sequestration 4 Bioenergy with Carbon Capture and Sequestration 5 Direct Air Capture 6 Carbon Mineralization of CO2 7 Sequestration of Supercritical CO2 in Deep Sedimentary Geological Formations 8 Synthesis Glossary Acronyms and Abbreviations References Appendix A: Committee Bios Appendix B: Disclosure of Conflict of Interest Appendix C: Coastal Blue Carbon:Macroalgae Appendix D: CO2 Flux Calculation Appendix E: Carbon Mineralization Appendix F: Geologic Storage

Understanding, quantifying, and tracking atmospheric methane and emissions is essential for addressing concerns and informing decisions that affect the climate, economy, and human health and safety. Atmospheric methane is a potent greenhouse gas (GHG) that contributes to global warming. While carbon dioxide is by far the dominant cause of the rise in global average temperatures, methane also plays a significant role because it absorbs more energy per unit mass than carbon dioxide does, giving it a disproportionately large effect on global radiative forcing. In addition to contributing to climate change, methane also affects human health as a precursor to ozone pollution in the lower atmosphere. Improving Characterization of Anthropogenic Methane Emissions in the United States summarizes the current state of understanding of methane emissions sources and the measurement approaches and evaluates opportunities for methodological and inventory development improvements. This report will inform future research agendas of various U.S. agencies, including NOAA, the EPA, the DOE, NASA, the U.S. Department of Agriculture (USDA), and the National Science Foundation (NSF). Table of Contents Front Matter Summary 1 Introduction 2 Current Inventories of Methane Emissions 3 Methane Emission Measurement and Monitoring Methods 4 Addressing Uncertainties in Anthropogenic Methane Emissions 5 Presenting Methane Emission Data and Results 6 Meeting the Challenges of Characterizing Methane Emissions References Glossary Appendix A: Acronyms and Abbreviations Appendix B: Definition of U.S. Greenhouse Gas Inventory Categories Appendix C: Other Anthropogenic Sources of Methane Appendix D: U.S. Greenhouse Gas Inventory Development Appendix E: Acknowledgment of Those Who Provided Input to the Committee Appendix F: Common Units for Reporting Methane Concentrations and Emissions Appendix G: Biographical Sketches of Committee Members Appendix H: Disclosure of Conflict of Interest

Our ability to observe and forecast severe weather events has improved markedly over the past few decades. Forecasts of snow and ice storms, hurricanes and storm surge, extreme heat, and other severe weather events are made with greater accuracy, geographic specificity, and lead time to allow people and communities to take appropriate protective measures. Yet hazardous weather continues to cause loss of life and result in other preventable social costs. There is growing recognition that a host of social and behavioral factors affect how we prepare for, observe, predict, respond to, and are impacted by weather hazards. For example, an individual's response to a severe weather event may depend on their understanding of the forecast, prior experience with severe weather, concerns about their other family members or property, their capacity to take the recommended protective actions, and numerous other factors. Indeed, it is these factors that can determine whether or not a potential hazard becomes an actual disaster. Thus, it is essential to bring to bear expertise in the social and behavioral sciences (SBS)?including disciplines such as anthropology, communication, demography, economics, geography, political science, psychology, and sociology?to understand how people's knowledge, experiences, perceptions, and attitudes shape their responses to weather risks and to understand how human cognitive and social dynamics affect the forecast process itself. Integrating Social and Behavioral Sciences Within the Weather Enterprise explores and provides guidance on the challenges of integrating social and behavioral sciences within the weather enterprise. It assesses current SBS activities, describes the potential value of improved integration of SBS and barriers that impede this integration, develops a research agenda, and identifies infrastructural and institutional arrangements for successfully pursuing SBS-weather research and the transfer of relevant findings to operational settings. Table of Contents Front Matter Summary 1 Introduction 2 The Motivation for Integrating Social and Behavioral Sciences Within the Weather Enterprise 3 Assessing the Current State of Social and Behavioral Sciences Within the Weather Enterprise 4 Social and Behavioral Sciences for Road Weather Concerns 5 Research Needs for Improving the Nation's Weather Readiness and Advancing Fundamental Social and Behavioral Science Knowledge 6 A Framework to Sustainably Support and Effectively Use Social and Behavioral Science Research in the Weather Enterprise 7 Summary of Key Findings and Recommendations References Appendix A: Examples of Funding for Social and Behavioral Science Activities by NOAA, NSF, DHS Appendix B: Lessons from SBS Integration into the "Public Health Enterprise" Appendix C: People Who Provided Input to the Committee Appendix D: Committee Biosketches Appendix E: Acronyms

The United States Global Change Research Program (USGCRP) is moving towards a sustained assessment process that allows for more fluid and consistent integration of scientific knowledge into the mandated quadrennial National Climate Assessment. As part of this process, the USGCRP is developing the Climate Science Special Report (CSSR), a technical report that details the current state-of-science relating to climate change and its physical impacts. The CSSR is intended to focus on climate change in the United States and to inform future USGCRP products. Review of the Draft Climate Science Special Report assesses whether the draft CSSR accurately presents the scientific literature in an understandable, transparent and traceable way; whether the CSSR authors handled the data, analyses, and statistical approaches in an appropriate manner; and the effectiveness of the report in conveying the information clearly for the intended audience. This report provides recommendations for how the draft CSSR could be strengthened. Table of Contents Front Matter Summary I. Introduction II. Synthesis of Comments on the Draft Climate Science Special Report III. Comments on Each Chapter of the Draft Climate Science Special Report References Appendix A: Line Comments Appendix B: Statement of Task Appendix C: Committee Biographies

The U.S. Global Change Research Program (USGCRP) is an interagency program, established by the Global Change Research Act (GCRA) of 1990, mandated by Congress to "assist the Nation and the world to understand, assess, predict, and respond to human-induced and natural processes of global change". Since the USGCRP began, scientific understanding of global change has increased and the information needs of the nation have changed dramatically. A better understanding of what is changing and why can help decision makers in the public and private sectors cope with ongoing change. Accomplishments of the U.S. Global Change Research Program highlights the growth of global change science in the quarter century that the USGCRP has been in existence, and documents some of its contributions to that growth through its primary functions of interagency planning and coordination, and of synthesis of research and practice to inform decision making. Table of Contents Front Matter Summary 1 Introduction 2 Strategic Planning and Coordination 3 Assessments and Stakeholder Engagement 4 Building on the Accomplishments of the USGCRP for the Next 25 Years References Acronyms Appendix A: Global Change Research Act of 1990 Appendix B: Statement of Task Appendix C: List of USGCRP Products Appendix D: List of National Academies Reports for the USGCRP Appendix E: Table of USGCRP Strategic Planning Goals and Objectives Appendix F: Committee Member Biographies

The U.S. Global Change Research Program (USGCRP) was established in 1990 to "assist the Nation and the world to understand, assess, predict, and respond to human-induced and natural processes of global change."1 A key responsibility for the program is to conduct National Climate Assessments (NCAs) every 4 years.2 These assessments are intended to inform the nation about "observed changes in climate, the current status of the climate, and anticipated trends for the future." The USGCRP hopes that government entities from federal agencies to small municipalities, citizens, communities, and businesses will rely on these assessments of climate- related risks for planning and decision-making. The third NCA (NCA3) was published in 2014 and work on the fourth is beginning. The USGCRP asked the Board on Environmental Change and Society of the National Academies of Sciences, Engineering, and Medicine to conduct a workshop to explore ways to frame the NCA4 and subsequent NCA reports in terms of risks to society. The workshop was intended to collect experienced views on how to characterize and communicate information about climate-related hazards, risks, and opportunities that will support decision makers in their efforts to reduce greenhouse gas emissions, reduce vulnerability to likely changes in climate, and increase resilience to those changes. Characterizing Risk in Climate Change Assessments summarizes the presentations and discussions from the workshop. Table of Contents Front Matter 1 Introduction 2 Characterizing and Communicating Risk 3 Cases: Methods and Approaches for Risk Assessment and Communication 4 Strategies for the Fourth National Climate Assessment References Appendix A: Workshop Agenda Appendix B: Biographical Sketches of Committee Members and Presenters

Many factors contribute to variability in Earth's climate on a range of timescales, from seasons to decades. Natural climate variability arises from two different sources: (1) internal variability from interactions among components of the climate system, for example, between the ocean and the atmosphere, and (2) natural external forcings, such as variations in the amount of radiation from the Sun. External forcings on the climate system also arise from some human activities, such as the emission of greenhouse gases (GHGs) and aerosols. The climate that we experience is a combination of all of these factors. Understanding climate variability on the decadal timescale is important to decision-making. Planners and policy makers want information about decadal variability in order to make decisions in a range of sectors, including for infrastructure, water resources, agriculture, and energy. In September 2015, the National Academies of Sciences, Engineering, and Medicine convened a workshop to examine variability in Earth's climate on decadal timescales, defined as 10 to 30 years. During the workshop, ocean and climate scientists reviewed the state of the science of decadal climate variability and its relationship to rates of human-caused global warming, and they explored opportunities for improvement in modeling and observations and assessing knowledge gaps. Frontiers in Decadal Climate Variability summarizes the presentations and discussions from the workshop. Table of Contents Front Matter Overview Introduction Challenges in Examining Climate Trends Modes and Mechanisms of Internal Variability The Role of External Forcing Overcoming Data Limitations Toward Predictability Frontiers and Research Opportunities References Appendix A: Statement of Task Appendix B: Planning Committee Biographical Sketches Appendix C: Workshop Agenda Appendix D: Workshop Participants Appendix E: Panel Presentation Abstracts Appendix F: Song Lyrics

The Update to the Strategic Plan (USP) is a supplement to the Ten-Year Strategic Plan of the U.S. Global Change Research Program (USGCRP) completed in 2012. The Strategic Plan sets out a research program guiding thirteen federal agencies in accord with the Global Change Research Act of 1990. This report reviews whether USGCRP's efforts to achieve its goals and objectives, as documented in the USP, are adequate and responsive to the Nation's needs, whether the priorities for continued or increased emphasis are appropriate, and if the written document communicates effectively, all within a context of the history and trajectory of the Program. Table of Contents Front Matter Summary Chapter 1: Introduction and Overview Chapter 2: Setting Priorities for Global Change Research Chapter 3: Science Focus and Scope Chapter 4: Review of Decision Suppor tObjectives and Plans Chapter 5: Concluding Comments References Appendix A: Statement of Task for This Report Appendix B: Overall Charge for the Advisory Committee to the U.S. Global Change Research Program Appendix C: Committee Biographies Appendix D: Line-by-line Comments Submitted by Committee Members Appendix E: Goals and Objectives in the 2012 USGCRP Strategic Plan

Climate change, driven by increases in human-produced greenhouse gases and particles (collectively referred to as GHGs), is the most serious environmental issue facing society. The need to reduce GHGs has become urgent as heat waves, heavy rain events, and other impacts of climate change have become more frequent and severe. Since the Paris Agreement was adopted in 2015, more than 136 countries, accounting for about 80% of total global GHG emissions, have committed to achieving net-zero emissions by 2050. A growing number of cities, regional governments, and industries have also made pledges to reduce emissions. Providing decision makers with useful, accurate, and trusted GHG emissions information is a crucial part of this effort. This report examines existing and emerging approaches used to generate and evaluate GHG emissions information at global to local scales. The report develops a framework for evaluating GHG emissions information to support and guide policy makers about its use in decision making. The framework identifies six criteria or pillars that can be used to evaluate and improve GHG emissions information: usability and timeliness, information transparency, evaluation and validation, completeness, inclusivity, and communication. The report recommends creating a coordinated repository or clearinghouse to operationalize the six pillars, for example, by providing timely, transparent, traceable information; standardized data formats; and governance mechanisms that are coordinated, trusted, and inclusive of the global community. Table of Contents Front Matter Summary 1 Introduction 2 Current Approaches for Quantifying Anthropogenic Greenhouse Gas Emissions 3 Structural and Technical Limitations of the Current Greenhouse Gas Emissions Information Landscape 4 Framework for Evaluating Greenhouse Gas Emissions Information 5 Recommendations References Appendix A: Acronyms, Initialisms, and Glossary Appendix B: Atmospheric Observations: Methods and Examples Appendix C: Contributors of Input to the Study Appendix D: Biographical Sketches of Committee Members Appendix E: Disclosure of Unavoidable Conflicts of Interest

Detailed weather observations on local and regional levels are essential to a range of needs from forecasting tornadoes to making decisions that affect energy security, public health and safety, transportation, agriculture and all of our economic interests. As technological capabilities have become increasingly affordable, businesses, state and local governments, and individual weather enthusiasts have set up observing systems throughout the United States. However, because there is no national network tying many of these systems together, data collection methods are inconsistent and public accessibility is limited. This book identifies short-term and long-term goals for federal government sponsors and other public and private partners in establishing a coordinated nationwide "network of networks" of weather and climate observations. Table of Contents Front Matter Summary 1 Introduction 2 Observations Supporting the Fundamental Infrastructure for Mesoscale Monitoring and Prediction 3 National Needs for Mesoscale Observations in Five Economic Sectors 4 Observing Systems and Technologies: Successes and Challenges 5 Architecture for a Network of Networks 6 How to Get from Here to There: Steps to Ensure Progress 7 Organizational Attributes and Options for a Fully Integrated NoN that Meets Multiple National Needs 8 Concluding Thoughts References Appendix A: A Rationale for Choosing the Spatial Density and Temporal Frequency of Observations for Various Atmospheric Phenomena Appendix B: Tables of Surface-Based Observing Systems Appendix C: Acronyms and Initialisms Appendix D: Statement of Task Appendix E: Biographical Sketches of Committee Members and Staff

The report explores how best to communicate weather and climate information by presenting five case studies, selected to illustrate a range of time scales and issues, from the forecasting of weather events, to providing seasonal outlooks, to projecting climate change.

Weather radar is a vital instrument for observing the atmosphere to help provide weather forecasts and issue weather warnings to the public. The current Next Generation Weather Radar (NEXRAD) system provides Doppler radar coverage to most regions of the United States (NRC, 1995). This network was designed in the mid 1980s and deployed in the 1990s as part of the National Weather Service (NWS) modernization (NRC, 1999). Since the initial design phase of the NEXRAD program, considerable advances have been made in radar technologies and in the use of weather radar for monitoring and prediction. The development of new technologies provides the motivation for appraising the status of the current weather radar system and identifying the most promising approaches for the development of its eventual replacement. The charge to the committee was to determine the state of knowledge regarding ground-based weather surveillance radar technology and identify the most promising approaches for the design of the replacement for the present Doppler Weather Radar. This report presents a first look at potential approaches for future upgrades to or replacements of the current weather radar system. The need, and schedule, for replacing the current system has not been established, but the committee used the briefings and deliberations to assess how the current system satisfies the current and emerging needs of the operational and research communities and identified potential system upgrades for providing improved weather forecasts and warnings. The time scale for any total replacement of the system (20- to 30-year time horizon) precluded detailed investigation of the designs and cost structures associated with any new weather radar system. The committee instead noted technologies that could provide improvements over the capabilities of the evolving NEXRAD system and recommends more detailed investigation and evaluation of several of these technologies. In the course of its deliberations, the committee developed a sense that the processes by which the eventual replacement radar system is developed and deployed could be as significant as the specific technologies adopted. Consequently, some of the committee's recommendations deal with such procedural issues.

A Climate Services Vision: First Steps Toward the Future describes the types of products that should be provided through a climate service; outlines the roles of the public, private, and academic sectors in a climate service; describe fundamental principles that should be followed in the provision of climate services; and describes potential audiences and providers of climate services. Table of Contents Front Matter Executive Summary 1 Introduction 2 Evolution of Climate Services in the United States 3 Guiding Principles for Climate Services 4 First Step Toward an Effective Climate Service References Acronyms and Abbreviations Board Members' Biographies Appendix A: Statement of Task Appendix B: Workshop Participants Appendix C: Agenda Appendix D: Examples of Areas of Climate Information Requests

Wildland fires pose a growing threat to air quality and human health. Fire is a natural part of many landscapes, but the extent of area burned and the severity of fires have been increasing, concurrent with human movement into previously uninhabited fire-prone areas and forest management practices that have increased fuel loads. These changes heighten the risk of exposure to fire itself and emissions (smoke), which can travel thousands of miles and affect millions of people, creating local, regional, and national air quality and health concerns. To address this growing threat, the National Academies brought together atmospheric chemistry and health research communities, natural resource managers, and decision makers to discuss current knowledge and needs surrounding how wildland fire emissions affect air quality and human health. Participants also explored opportunities to better bridge these communities to advance science and improve the production and exchange of information. This publication summarizes the workshop discussions and themes that emerged throughout the meeting. Table of Contents Front Matter Overview Introduction Wildfires and Human Health - An Overview Where Are We Now? Where Do We Want to Be? How Do We Get There? References Appendix A: Statement of Task Appendix B: Planning Committee Biographical Sketches Appendix C: Workshop Agenda