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Review of NASA's Earth Science Enterprise Research Strategy for 2000-2010 In particular, the five ESE research themes (oceans and ice, ecosystems, atmospheric chemistry, global water and energy cycle, and solid-Earth science) are directly applicable to the first three issues—variability, forcings, and feedbacks—although they are less well matched with the fourth and fifth issues, consequences and predictions. The primary science issues (Table 2) are given priority in planning the ESE program. The primary science issues are also consistent with the objectives of the USGCRP (Table 2) and with the spirit of the integrated Earth system science approach adopted previously by NASA and reiterated by the NRC report Global Environmental Change: Research Pathways for the Next Decade,8 referred to here as the Pathways report. The committee believes that addressing these primary science issues establishes a firm foundation for the Earth Science Enterprise. Table 2. Comparison of ESE Science Issues and USGCRP Objectives ESE Primary Science Issues USGCRP Objectivesa Earth's natural variability Primary forcings of the global Earth system Responses of the Earth system to natural and human-induced disturbances Consequences of changes in the Earth system for human societies Prediction of future changes in the Earth climate and global environment Determine the origins, rates, and likely future course of natural and anthropogenic changes Understand and model global environmental change and its processes on finer spatial scales and across a wide range of time scales Increase understanding of the combined effects of multiple stresses on ecosystems Understand and assess the impacts of global environmental change and their consequences for the United States Address the potential for surprises and abrupt changes in the global environment a Subcommittee on Global Change Research, 1999, Our Changing Planet: The FY2000 U.S. Global Change Research Program Implementation Plan and Budget Overview. Washington, D.C., 100 pp. IV. THE DETAILED SCIENCE QUESTIONS Because the primary science issues listed in Table 2 are too broad to guide implementation, NASA has also formulated 23 detailed science questions (see Table 3). The Plan's discussion of these questions includes both the scientific rationale for the questions and the quantities (parameters, implementation details, technical readiness, operational potential, and partnership potential) needed to answer them. The committee's analysis of the soundness of the selection of the detailed questions, and their consistency with recommendations made in NRC reports9,10,11,12,13,14,15,16,17,18,19,20,21,22,23 is given below. 8 NRC, 1998, Global Environmental Change: Research Pathways for the Next Decade. National Academy Press, Washington, D.C., 595 pp. 9 NRC, 1998, Global Environmental Change: Research Pathways for the Next Decade. National Academy Press, Washington, D.C., 595 pp. 10 NRC, 1999, Hydrologic Science Priorities for the U.S. Global Change Research Program. National Academy Press, Washington, D.C., 34 pp. 11 NRC, 1998, Global Energy and Water Cycle Experiment (GEWEX) Continental-Scale International Project: A Review of Progress and Opportunities. National Academy Press, Washington, D.C., 93 pp.
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Review of NASA's Earth Science Enterprise Research Strategy for 2000-2010 Questions Related to Earth System Variability and Trends The first recommendation of the Pathways report is that “. the USGCRP strategy should be centered on sharply defined and effectively executed programs and should recognize the essential need for focused observations, both space-based and in situ, to test scientific hypotheses and document changes” (p. 521). All the detailed ESE questions related to Earth system variability and trends concern documenting change, and all are responsive to various relevant NRC reports (see Table 3). However, several key aspects integral to understanding the basic state of the Earth system, and Earth system variability and change, are missing. For example, question V2 deals with changes in the global ocean on climatic time scales, but not changes in the atmosphere, land, or sea ice. Similarly, question V4, which deals with changes in stratospheric ozone, does not mention tropospheric chemistry trends, even though it is a major research emphasis within the ESE. Variability in ecosystems and in chemical systems is not explicitly discussed. Finally, the dominant climate modes (i.e., El Niño/Southern Oscillation, Pacific (inter)Decadal Oscillation, North Atlantic Oscillation) are treated in a fragmentary manner without a clear strategy for putting the pieces together, as required in an Earth system science approach. The table in the Plan associated with these detailed questions (Table 4.1) identifies remotely sensed quantities, but in situ measurements are almost always required to completely answer Earth science questions. For example, remote sensing measurements are not sufficient to document changes in the global ocean circulation (question V2), for which in situ measurements are essential. Identifying the complementary observations for addressing questions V1-V6 would be a useful addition to the next version of the Plan. 12 NRC, 1997, Satellite Gravity and the Geosphere: Contributions to the Study of the Solid Earth and Its Fluid Envelope. National Academy Press, Washington, D.C., 112 pp. 13 NRC, 1997, The Global Ocean Observing System: Users, Benefits, and Priorities. National Academy Press, Washington, D.C., 82 pp. 14 NRC, 1998, Decade-to-Century-Scale Climate Variability and Change. National Academy Press, Washington, D.C., 142 pp. 15 NRC, 1995, Understanding Marine Biodiversity: A Research Agenda for the Nation. National Academy Press, Washington, D.C., 128 pp. 16 NRC, 1994, Priorities for Coastal Ecosystem Science. National Academy Press, Washington, D.C., 106 pp. 17 NRC, 2000, Global Change Ecosystems Research. National Academy Press, Washington, D.C., in press. 18 NRC, 1998, The Atmospheric Sciences Entering the 21st Century. National Academy Press, Washington, D.C., 364 pp. 19 NRC, 1991, International Global Network of Fiducial Stations: Scientific and Implementation Issues. National Academy Press, Washington, D.C., 129 pp. 20 NRC, 1998, Opportunities in Ocean Sciences: Challenges on the Horizon. National Academy Press, Washington, D.C., 6 pp. 21 NRC, 2000, Clean Coastal Waters: Understanding and Reducing the Effects of Nutrient Pollution. National Academy Press, Washington, D.C., 405 pp. 22 NRC, 1999, From Monsoons to Microbes: Understanding the Ocean's Role in Human Health. National Academy Press, Washington, D.C., 132 pp. 23 NRC, 1998, A Scientific Strategy for U.S. Participation in the GOALS (Global Ocean-Atmosphere-Land System) Component of the CLIVAR (Climate Variability and Predictability) Programme. National Academy Press, Washington, D.C., 69 pp.
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Review of NASA's Earth Science Enterprise Research Strategy for 2000-2010 Table 3. Consistency of ESE Science Questions with Recommendations Made in NRC reports ESE Science Questions NRC Referencea Earth's Natural Variability and Trends V1 Is the global cycling of water through the atmosphere accelerating? V2 How is the global ocean circulation varying on climatic time scales? V3 How are global ecosystems changing? V4 How is stratospheric ozone changing, as the abundance of ozone-destroying chemicals decreases? V5 Are polar ice sheets losing mass as a result of climate change? V6 What are the motions of the Earth and the Earth's interior, and what information can be inferred about Earth's internal processes? 9, 10, 11 12, 13, 14 9, 15, 16, 17 9, 18 12, 14, 19 12, 19 Primary Forcings of the Global Earth System F1 What trends in atmospheric constituents and solar radiation are driving global climate? F2 What are the changes in global land cover and land use, and what are their causes? F3 How is the Earth's surface being transformed and how can such information be used to predict future changes? 9, 18 9, 17 17, 19 Responses of the Earth System to Natural and Human-Induced Disturbances R1 What are the effects of clouds and surface hydrologic processes on climate change? R2 How do ecosystems respond to environmental change and affect the global carbon cycle? R3 Will climate variations induce major changes in the deep ocean? R4 How do stratospheric trace constituents respond to climate change and chemical agents? R5 Will changes in polar ice sheets cause a major change in global sea level? R6 What are the effects of regional pollution on the global atmosphere, and the effects of global chemical and climate changes on regional air quality? 11, 18 9, 10, 15, 16, 17, 20 13 9 12 9, 18 Consequences of Changes in the Earth System for Human Societies C1 How are variations in local weather, precipitation and water resources related to global climate change? C2 What are the consequences of land cover and land use change? C3 To what extent are changes in coastal regions related to climate change and sea-level rise? 9, 11, 18 9, 10, 15, 17, 21, 22 9, 16, 20
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Review of NASA's Earth Science Enterprise Research Strategy for 2000-2010 Prediction of Future Changes in the Earth Climate and Global Environment P1 To what extent can weather forecasting be improved by new global observations and advances in satellite data assimilation? P2 To what extent can transient climate variations be understood and predicted? P3 To what extent can long-term climatic trends be assessed or predicted? P4 To what extent can future atmospheric chemical impacts be assessed? P5 To what extent can future atmospheric concentrations of carbon dioxide and methane be predicted? 13, 18 9, 13, 14, 18 9, 18 9, 21 9 a The full references are given in the correspondingly numbered footnotes on pages 5 and 6. Questions Related to Forcing and Response The construct of forcing and response leads to a set of questions that are broadly consistent with recommendations made in several NRC reports (Table 3). However, it also emphasizes questions that deal with relatively long time scales, an approach that eliminates most issues of natural Earth system variability on seasonal-to-interannual and decadal-to-centennial scales. Thus, the forcing-related questions address long-term changes in solar radiation, atmospheric constituents, land-use changes, and landform-surface changes. The response-related questions focus on the longer-term responses of clouds, ecosystems, the deep ocean, the stratosphere, the polar ice sheets, and air quality. There is, however, no mention of forcing due to volcanoes, which is relevant to atmospheric chemistry and understanding the Earth system. Some of the questions, particularly questions related to Earth system responses and feedback processes, should be stated in more general terms. Questions R3 and R5, in particular, could be answered “yes ” now. Yet, the issues encompassed by these questions are important and should be captured in the phrasing. Question R5 would be better posed as a query regarding sea level rise in response to long-term climate change, wording that would imply the study of ocean warming and related sea level rise, as well as changes within the cryosphere as a function of time and space. Question R3 could be rephrased to focus on processes. The shift in focus from short-term measurements, which NASA has traditionally emphasized, toward long-term monitoring, which NASA has not interpreted as part of its mission, appears to be intentional (see “NASA's Responsibility for Answering the Detailed Science Questions” below). If that is the case, the ESE will have to define a strategy for (1) conducting long-term monitoring, (2) obtaining in situ observations, and (3) combining and synthesizing both types of observations in models so that the ESE science questions on Earth system variability (especially trends) and on forcing and response can be answered. Questions Related to the Consequences of Global Change The ESE science questions on the consequences of global change are posed as socially relevant issues: effects of global change on weather, precipitation patterns, water resources, land-use changes, and sea-level rise. These questions carry a requirement for long-term monitoring, but they also have a specific human dimension that links the science to societal concerns. Because NASA does not have strength in social science research, it must seek experts with the requisite
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Review of NASA's Earth Science Enterprise Research Strategy for 2000-2010 knowledge and/or form partnerships with other agencies and organizations to address these questions.24 Questions Related to Global Prediction and Assessments Addressing the questions on global change prediction and assessment involves synthesis of knowledge and understanding as a basis for improved predictive capability. All require significant modeling, data assimilation, analysis, and partnerships with other agencies and organizations. For example, responding to question P1 on weather forecasting depends on the involvement of the weather prediction community (e.g., NOAA's National Centers for Environmental Prediction). Question P1, however, does not represent a global change issue because its focus is weather forecasting on short time scales. A more accurate label for the primary science issue would be Earth System Science Predictions or Assessments. Question P2 relates to the seasonal-to-interannual and decadal-to-centennial prediction and predictability at the heart of the Pathways report imperatives. However, whether the question can be answered is open to doubt because of shortcomings in the planned observational effort (see “Questions Related to Earth System Variability and Trends ” above). Answering certain of the 19 questions listed in the four preceding science issues in Table 3 will clearly help in predicting climate variability, but answering all of the previous questions will not lead to answering P2. The same is true for questions P3 to P5, which deal with long-term climate trends and changes in atmospheric chemistry. Summary Comments—Detailed Science Questions The detailed science questions in the Plan reflect previous NASA planning documents, such as the EOS Science Plan,25 and are responsive to the recommendations of various NRC reports. All the questions are worthy of being addressed. Many other detailed science questions within NASA's purview, however, are relevant to the five primary science issues and are not included in the Plan. (See, for example, the discussion in “Questions Related to Earth System Variability and Trends” above.) Moreover, the Plan does not acknowledge or discuss a number of capabilities and programs within NASA (e.g., ENSO research, tropospheric chemistry research, the Applications program) that would be integral to answering the detailed questions. Finally, the wording of the questions should emphasize understanding, rather than description. The Plan should be modified to include a brief discussion of how ESE's five research themes and other relevant but unmentioned NASA programs relate to the detailed science questions. Recommendation 1. NASA should ensure either (a) that the revised Plan's detailed science questions reflect all of the major research and programmatic elements of ESEs current science program (e.g., ENSO, trends in tropospheric chemistry) or (b) that the revised Plan explains clearly why the science questions do not include certain ESE research and program elements. 24 A discussion of the challenges and opportunities in bridging the social science and remote sensing fields can be found in NRC, 1998, People and Pixels: Linking Remote Sensing and Social Science. National Academy Press, Washington, D.C., 244 pp. 25 NASA, 1999, EOS Science Plan: The State of Science in the EOS Program. Washington, D.C., 397 pp.
Representative terms from entire chapter: