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Questioning the Effectiveness of U.S. Climate Modeling

Over the last 30 years, data have revealed that the global climate is naturally variable on many time scales (ranging from years to centuries and longer) and may be changing in response to anthropogenic inputs of radiatively active gases. The public and private sectors have become increasingly concerned with the potential impacts of this change. In response, the research community has been working to provide societally beneficial information (e.g., NRC, 1999d), which has led to dramatic increases in requests for climate information products, particularly those that can be used to understand the impacts of climate changes and evaluate strategies for dealing with them. Mathematical models based on the laws of environmental physics and sound scientific measurements are the primary tool that can be used to provide these products. When coupled with descriptions of the social, political, technical, and economic impacts, these models have the potential to predict future socio-economic changes resulting from climate changes (e.g., Nordhaus and Boyer, 2000).

Recognizing the societal importance of climate modeling, the National Research Council published a report entitled Capacity of U.S. Climate Modeling to Support Climate Assessment Activities (NRC, 1998a). This report evaluated the allocations of resources to high-end climate modeling and whether these resources were being used effectively. The full text of the Executive Summary of this report is given in Appendix B. The report concluded that, while small- and intermediate-scale climate modeling in the United States is effective and enjoying both national and international prominence, climate modeling at the highest end is lagging because of a lack of coordination among agencies, a lack of human and



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Improving the Effectiveness of U.S. Climate Modeling 1 Questioning the Effectiveness of U.S. Climate Modeling Over the last 30 years, data have revealed that the global climate is naturally variable on many time scales (ranging from years to centuries and longer) and may be changing in response to anthropogenic inputs of radiatively active gases. The public and private sectors have become increasingly concerned with the potential impacts of this change. In response, the research community has been working to provide societally beneficial information (e.g., NRC, 1999d), which has led to dramatic increases in requests for climate information products, particularly those that can be used to understand the impacts of climate changes and evaluate strategies for dealing with them. Mathematical models based on the laws of environmental physics and sound scientific measurements are the primary tool that can be used to provide these products. When coupled with descriptions of the social, political, technical, and economic impacts, these models have the potential to predict future socio-economic changes resulting from climate changes (e.g., Nordhaus and Boyer, 2000). Recognizing the societal importance of climate modeling, the National Research Council published a report entitled Capacity of U.S. Climate Modeling to Support Climate Assessment Activities (NRC, 1998a). This report evaluated the allocations of resources to high-end climate modeling and whether these resources were being used effectively. The full text of the Executive Summary of this report is given in Appendix B. The report concluded that, while small- and intermediate-scale climate modeling in the United States is effective and enjoying both national and international prominence, climate modeling at the highest end is lagging because of a lack of coordination among agencies, a lack of human and

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Improving the Effectiveness of U.S. Climate Modeling computer resources devoted to the highest end of modeling, and a lack of an integrated national strategy for high-end modeling efforts. It further concluded that (1) the United States lags behind other nations in its ability to model long-term climate; (2) it is inappropriate for the United States to depend on other countries to provide high-end climate modeling capabilities; and (3) this dependence should be redressed by improving the capabilities within the United States. Finally, it concluded that “to facilitate future climate assessments, climate treaty negotiations, and our understanding and predictions of climate, it is appropriate to develop now a national climate modeling strategy that includes the provision of adequate computational and human resources and is integrated across agencies.” This present study focuses on the challenges posed in the 1998 report (NRC, 1998a) as specified in the statement of task given to the panel ( Box 1-1). To address these tasks, the Panel on Improving the Effectiveness of U.S. Climate Modeling met three times and held a one-day workshop Box 1-1 Statement of Task The purpose of this study is to provide relevant federal agencies and the scientific community with an assessment of the nation's technical modeling needs and a vision of how government, interacting with the rest of the scientific community, can optimize the use of modeling talents in the United States. This study will thus address the challenges posed in the Climate Research Committee's 1998 report, Capacity of U.S. Climate Modeling to Support Climate Change Assessment Activities. In pursuit of these objectives, the panel will produce a report that: Examines the major types of climate modeling, paying particular attention to both the similarities (e.g., potential synergisms) and unique characteristics of each. Specific issues to be addressed include: model construction and testing, data input and archival, ensemble simulation, interrogation and diagnostics, evaluation, and operational utilization. Describes the computational and human resources required to effectively conduct climate modeling in the United States to meet the needs of the climate applications, policy, and scientific communities. This evaluation will include consideration of shifts in computational architectures and potential for and cost of improvements in model codes. It will also consider the utilization of common climate modeling tools, protocols, and data, and the availability of cooperative opportunities between different scales of modeling effort and institutions. Quantitatively assesses the computational and human resources that are presently directed toward climate modeling in the United States. Describes ways in which the efficacy of the U.S. climate modeling enterprise might be improved, given the current needs and resources. The report will define a set of issues that are fundamental to the enhancement and sustenance of climate modeling in the United States.

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Improving the Effectiveness of U.S. Climate Modeling with approximately 50 participants from the climate modeling community. This workshop was designed to gather information on community perceptions of the current state of climate modeling and possible responses ( Appendix F). To quantitatively assess the computational and human resources presently directed towards U.S. climate modeling, two surveys were developed (Appendix Cand Appendix D). One survey was sent to large 1and intermediate-size 2 modeling centers and one was sent to modelers who conducted workstation 3 scale modeling (“small” in the words of NRC, 1998a). Survey responses are tabulated in Appendix E. Issues related to climate modeling have been the focus of a number of recent reports (summarized in Appendix H). The key issues and concerns arising from these reports that helped structure this study include: the lack of adequate access to high-end computing by the climate modeling community; the scarcity of human resources applied to computational and scientific research problems; the difficulty of matching the financial rewards offered by private industry; the lack of appropriate software available to optimize performance on the new generations of massively parallel computers; the lack of software standards and protocols for building different climate models and the absence of uniform computer and observational data-archiving standards, which inhibits exchange of useful information; the need for uniform criteria with which to judge climate models; the need for widely available standard software tools to diagnose and compare climate model output; the need for a strong interaction between observations of the climate system, research into fundamental climate processes, and integrative climate modeling. Traditionally, climate modeling has been devoted to perfecting the understanding of the climate system. This has been done by the climate research community through competitive proposals that required little interagency coordination and no general strategy for success. Increasingly, however, modeling efforts have been directed towards the produc- 1   In this document a large or high-end effort is one using a global, coupled T42 (2.8° × 2.8°) atmospheric / 2° × 2° oceanic model (or finer resolution) for centennial-scale simulations of transient climate change. 2   In this document an intermediate center is one using a global, stand alone atmospheric climate model at T42 (2.8° × 2.8°) resolution. 3   In this document a small modeling center is that which uses a global, stand alone atmospheric climate model at R15 (~4.5° × 7.5°) resolution.

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Improving the Effectiveness of U.S. Climate Modeling tion of climate information products in response to the societal demands. 4 The interaction between researchers and users is then critical to determining what ought to be predicted and the limits and uncertainties of the predictions (Hooke and Pielke, 2000). The prediction products would then provide information and support decisions about agriculture, energy, health, transportation, food aid, disaster response, and other climatically influenced activities. This desire for information products and climate change assessments has been a primary motivator for increasing the accuracy of climate model outputs, particularly those modeling the climatic response to anthropogenically produced, radiatively active constituents. Similarly, advances in the ability to predict seasonal-to-interannual climate variations associated with the El Niño/Southern Oscillation have led to public and private demands for skillful predictions and for research on better ways of using the information (NRC, 1999c). Increased societal demands for climate information products have had significant impacts on the research community, which, both by limited capacity and by culture, is increasingly unable to respond to these demands. Because the need for climate model products affects the current state of climate modeling science, a discussion of the impacts of these demands on the research community is included in this report. This situation is organizationally similar to that in the weather arena, where daily and weekly forecasts are provided for widespread public and private use by a service organization dedicated to that task, rather than by solicitation of proposals from the weather research community. The production of operational products in the weather community provides an organizational and institutional paradigm that can be applied to the climate situation. This report will analyze the present capability for climate modeling in the United States, the current ability to respond to assessment, and prediction requirements. It will describe the new requirements being placed on high-end climate modeling and discuss the computer, human, and organizational resources needed to respond to these requirements. This is followed by findings and recommendations designed to improve the ability of the climate community to meet these new challenges. The report ends with a vision for how climate research, global observations, and comprehensive climate modeling could be combined for the benefit of science and society. 4   The term “demand” is not used in this report in the strictest economic sense. Additionally, references to societal demands, imperatives, and needs in this report are based on panel members' individual experiences and interactions with specific societal uses as well as the perceptions of potential users of a broad range of climate modeling products and services. These terms also reflect the increased reliance of regional and national assessments on climate models. This latter point is addressed further in chapter 4.