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4 Progress Toward the Research Elements T his chapter presents the committee’s stage 1 analysis of the Climate Change Science Program (CCSP) research elements. The preliminary assessment was structured around the matrix (Appendix C), which evaluates progress of the 33 research questions in five categories: (1) data and physical quantities, (2) understanding and representation of processes, (3) uncertainty, predictability, or predictive capabilities, (4) synthesis and assessment, and (5) risk management and decision support. The goal was to highlight the most important issues, as identified by the peer-review workshop, not to provide an exhaustive analysis of every aspect of each research question. Consequently, although scores and commentary were assigned to all 165 cells in the matrix, this chapter reports only an overall qualitative score (good, fair, inadequate) and key comments for each re- search question. The scores are defined as follows: • Good = The quality and contribution of work exceeds expectation. • Fair = The quality and contribution of work merely meets expecta- tion. Additional review may be warranted to increase effectiveness. • Inadequate = The quality and contribution of work does not meet the needs of the program. Additional review to explain the poor results is required. Recurring themes and trends are discussed under “Opportunities and Threats” for each research element. The chapter concludes with an example 51

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52 EVALUATING PROGRESS OF THE U.S. CCSP of how progress in the overarching goals can be evaluated, based on scores for the relevant research questions. ATMOSPHERIC COMPOSITION The composition of the atmosphere plays a critical role in connect- ing human welfare with climate changes because the atmosphere links the principal components of the Earth system. Emissions of gases and particles from natural sources and human activities enter the atmosphere and are transported to other geographical locations and often to higher altitudes. Some emissions undergo chemical transformation or removal while in the atmosphere or influence cloud formation and precipitation. Changes in atmospheric composition alter the greenhouse effect and the reflection and absorption of solar radiation, which modifies the Earth’s radiative (energy) balance. Subsequent feedbacks and responses to this human-in- duced climate forcing influence human health and natural systems in a variety of ways. Observed trends in atmospheric composition are among the earliest harbingers of environmental change. Because the atmosphere acts as a long-term reservoir for certain trace gases, any associated global changes could persist for decades or even millennia, affecting all countries and populations. The CCSP approach to understanding the role of atmospheric composi- tion integrates long-term (multidecadal) systematic observations, laboratory and field studies, and modeling, with periodic assessments of understanding and significance to decision making. Most of the activities related to the atmospheric composition research element are carried out through national and international partnerships, partly because of the breadth and complex- ity of the science and policy issues and partly because the atmosphere links all nations. CCSP-supported research focuses on how the composition of the global atmosphere is altered by human activities and natural phenom- ena, and how such changes influence climate, ozone, ultraviolet (UV) radia- tion, pollutant exposure, ecosystems, and human health. Specific objectives address processes that affect the recovery of stratospheric ozone; properties and distributions of greenhouse gases and aerosols; long-range transport of pollutants and the implications for regional air quality; and integrated as- sessments of the effects of these changes. Interactions between atmospheric composition and climate variability and change, such as the potential effects of global climate change on regional air quality, are of particular interest. Progress Toward Answering the Research Questions In situ and satellite measurements and field campaigns have yielded rich data sets and improved estimates of physical quantities for all five questions

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5 PROGRESS TOWARD THE RESEARCH ELEMENTS under this research element. Gaps remain, however. Similarly, gains in our understanding and representation of many key physical processes have been substantial, although large uncertainties about the indirect effect of aerosols on climate, poor quantification of aerosol solar absorption, and the absence of aerosol-cloud-precipitation interactions in coupled models remain major shortcomings. Great uncertainties also remain in our knowledge of the radiative forcing of non-CO2 gases (e.g., tropospheric ozone). Although predictions of air quality and ozone have improved, the predictability of the impact of pollutants on human health and especially on ecosystems is still limited. Finally, although we have sufficient understanding of some atmospheric species (e.g., sulfates and nitrates) to promote action, the same is not true for other aerosols (e.g., elemental and organic carbon) and non- CO2 greenhouse gases. Q .1. What are the climate-relevant chemical, microphysical, and optical properties, and spatial and temporal distributions, of human-caused and naturally occurring aerosols? Good scientific progress has been made on several fronts (e.g., observa- tionally constrained aerosol direct forcing), but large uncertainties remain (e.g., emission sources, indirect effect of aerosols on climate). Progress in aerosol observations has enabled the Intergovernmental Panel on Climate Change (IPCC) to quantify for the first time the net contribution of aerosols to anthropogenic forcing (IPCC, 2007). Significant CCSP investments in this question reflect growing recognition of the importance of aerosols and their role in climate. A wealth of new data from space and ground measurements have been used effectively to generate physical properties such as aerosol absorption and anthropogenic fraction on a global scale. These data sets provided the first information on how aerosols are transported from land regions to oceanic regions. For example, the CCSP sponsored field experi- ments on transport and transformation processes in aerosol plumes off the east coasts of Asia and North America. Data from ground stations in the western United States have shown that springtime background aerosol in that region is Asian in origin (Heald et al., 2006b). The Indian Ocean Ex- periment and the Asian Pacific Regional Aerosol Characterization Experi- ment field campaign revealed that satellite-derived maps of aerosol optical depth and aerosol mixture (air-mass type) extent, combined with targeted in situ component microphysical property measurements, can provide a detailed global picture of aerosol properties and distributions and their direct radiative forcing (Chung et al., 2005; Yu et al., 2006). Such investiga- tions provided the first observationally constrained estimates of the effect of anthropogenic aerosols on climate. Another major advance is the first measurement of the effect of aerosols, including sunlight-absorbing black

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5 EVALUATING PROGRESS OF THE U.S. CCSP carbon (soot), on the inhibition of cloud formation by the Moderate-Reso- lution Imaging Spectroradiometer (MODIS) (Kaufman et al., 2005a, b). There is still room for improvement, however. Large uncertainties remain about the emission sources of elemental and organic carbon, the indirect effect of aerosols on climate, and the extent of atmospheric solar absorption. Incorporation of aerosol-cloud interactions in coupled models has been slow. The CCSP has not undertaken a coordinated effort to evalu- ate future scenarios of changes in worldwide aerosol emissions, which seri- ously limits projections of future climate changes. Improved knowledge of aerosol forcing would have a major impact on decision support systems and policy actions: reductions in aerosols would reduce the aerosol masking ef- fect on global warming and accelerate greenhouse forcing over the next few decades. However, no coordinated efforts to provide information to climate modelers or to policy makers are apparent. Finally, understanding of some types of aerosols (e.g., sulfates, nitrates, elemental carbon) is insufficient to evaluate and promote specific actions. Q .2. What are the atmospheric sources and sinks of the greenhouse gases other than CO2 and the implications for the Earth’s energy balance? Good progress has been made on radiative forcing and sources and sinks of some greenhouse gases, such as methane, but uncertainties re- main for other greenhouse gases, limiting progress on decision support. Good measurements exist of most non-CO2 greenhouse gases (e.g., nitrous oxide, chlorofluorocarbons [CFCs], methane, carbon monoxide, ozone, hydrogen, hydrochlorofluorocarbons, hydrofluorocarbons, methyl halides, sulfur hexafluoride), although better measurements are required for some. Analyses have shown, for instance, that global methane abundances were constant for nearly seven years beginning in 1999, suggesting that methane may have reached a steady state in the atmosphere for reasons that are not yet known (Dlugokencky et al., 2003). The Aura satellite is providing the first-ever daily global measurements of tropospheric ozone and many other trace gases with unprecedented spatial resolution. A 350-year history of atmospheric carbonyl sulfide from an Antarctic ice core and firn air showed how atmospheric abundances of this gas have changed as a consequence of industrial sulfur emissions (Aydin et al., 2002). Researchers have also made good progress in understanding North American emissions of trace gases, which are precursors of the formation of aerosols and ozone (Heald et al., 2006a; Pfister et al., 2006). However, although good measurements exist, large uncertainties re- main in our knowledge of the radiative forcing of non-CO2 gases. Similarly, while the sources and sinks of many of these gases are better understood,

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55 PROGRESS TOWARD THE RESEARCH ELEMENTS unanswered questions on emission and removal processes remain. Many non-CO2 greenhouse gases are not yet included in global climate models. Q .. What are the effects of regional pollution on the global atmosphere and the effects of global climate and chemical change on regional air quality and atmospheric chemical inputs to ecosystems? Good progress has been made in describing the fate of anthropogenic emissions in the global atmosphere through new measurement techniques and observational studies, yet predictability is still limited. Considerable work has been done on this question. For instance, the National Aeronau- tics and Space Administration’s (NASA’s) Transport and Chemical Evolu- tion over the Pacific mission demonstrated the value of global satellite and airborne observations for improving knowledge of emissions inventories (Streets et al., 2003; Wang et al., 2005). Broad-based initiatives to study anthropogenic emissions in megacities are now under way (Guttikunda et al., 2005; Madronich, 2006). Data from the Aura satellite are being used to help monitor pollution production and transport between cities, regions, and continents on a daily basis for the first time. The International Consor- tium for Atmospheric Research on Transport and Transformation carried out the largest climate and air quality study to date, with a focus on devel- oping a better understanding of the factors involved in the intercontinental transport of pollution and the radiation balance in North America and the North Atlantic (Singh et al., 2006). Finally, a new technique that enables measurement of trace gases in the atmosphere has opened a new frontier on the atmospheric chemistry that occurs at night. Nighttime reactions in- volving nitrogen-containing trace gases can effectively remove these gases from the atmosphere, and “short-circuit” the chemical reactions that would have produced ozone the next day (Sillman et al., 2002; Ren et al., 2003). Although the understanding of atmospheric chemistry processes and the impact of pollutants on human health has improved, a number of complexities, especially on the regional scale, limit predictability. Under- standing of the heterogeneous chemistry from local to global scales is still not sufficient to include in global models and make predictions of future changes. Finally, uncertainties remain about longer-term trends (e.g., for tropospheric ozone) that are important for interpreting the historical global climate record (Lamarque et al., 2005). Q .. What are the characteristics of the recovery of the stratospheric ozone layer in response to declining abundances of ozone-depleting gases and increasing abundances of greenhouse gases?

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5 EVALUATING PROGRESS OF THE U.S. CCSP The recovery of stratospheric ozone is a success story, where decisions were made despite some scientific uncertainty. Recent advances in under- standing and modeling stratospheric transport and dynamics have since reduced these uncertainties. The Scientific Assessment of Ozone Depletion (WMO, 2003) summarizes current understanding of the ozone layer and the phenomenon of stratospheric ozone depletion. CCSP-sponsored work continues to improve knowledge of the atmospheric processes underlying ozone abundance at the poles and globally, to support satellite observations of ozone-depleting substances in the atmosphere, to revise expectations for recovery of the ozone layer, and to develop approaches to evaluate the im- pacts of very short-lived halogen-containing substances on the ozone layer. Ground-based measurements of ozone are now sufficiently accurate to validate the satellite data, and their temporal resolution is sufficiently fine to determine diurnal variations and understand observed trends over the last century or more. For example, nine years of radiometer data from the UV-B Monitoring and Research Program’s observational network has been used to assess the geographic distribution, trends, and year-to-year variability of UV-B radiation in the United States (Grant and Slusser, 2004). Progress is inadequate, however, on the critical exchange processes between the troposphere and the stratosphere, the feedback mechanisms between increasing concentrations of greenhouse gases and reduced levels of chlorofluorocarbons, and predictions of the amount of water vapor in the stratosphere. Q .5. What are the couplings and feedback mechanisms among climate change, air pollution, and ozone layer depletion, and their relationship to the health of humans and ecosystems? Improved decadal and longer term climate and ozone data have driven good progress in the description of the effects of long-term changes in stratospheric and tropospheric temperatures and circulation on ozone-layer depletion. However, predictability is still limited because of insufficient un- derstanding of the couplings between air pollution and climate change. This broad and complex question is tailor-made for the CCSP because it is inher- ently interdisciplinary and requires strong interagency cooperation. Strong leadership has led managers of fragmented programs to pool resources in this arena. Resulting field programs engendered by the CCSP have yielded good results, and fair progress has been made in understanding processes that link long-term (several decades) changes in temperatures and circula- tion with ozone depletion. The impacts of pollutants on human health in New York City have been studied (Drewnick et al., 2004), yet significant gaps remain in understanding the connections between atmospheric compo-

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5 PROGRESS TOWARD THE RESEARCH ELEMENTS sition and human health, and especially between atmospheric composition and ecosystem health (NRC, 2001c). It is still not possible to model the full range of aerosol constituents in polluted areas, primarily because of the inherent complexity of the prob- lem and secondarily because concentrations of organic aerosols in urban environments are still uncertain by a factor of ten. Local- to global-scale heterogeneity of cloud processing of aerosols and the subsequent modifi- cation of aerosol chemistry also remain very uncertain. Work in this area has not reached the stage where scientific understanding can support risk management and decision making. Opportunities and Threats A large amount of high-quality satellite and in situ data, increasing computational resources, and sophisticated models have led to good prog- ress in understanding the factors that alter atmospheric composition and how these alterations affect climate, humans, and ecosystems. However, the absence of a well-coordinated national effort is limiting progress in improving aerosol emission strengths globally, estimating past histories of biomass burning, and determining the vertical distribution of aerosols and their solar absorption. Another major issue is that while satellite data are currently a rich resource, primarily because of the investment that began in the 1990s with NASA’s Earth Observing System, the future looks relatively bleak. The recent National Polar-orbiting Environmental Satellite System (NPOESS) downscale has eliminated several key climate instruments, such as the aero- sol polarization sensor (NRC, 2007a). Moreover, since most climate records require overlapping intercalibration to ensure accurate climate monitoring, future gaps in high-quality data will in many cases restart the climate record (NRC, 1998, 2004b; Trenberth et al., 2006). Such gaps are now likely, and since satellites require 5 to 10 years of advance planning, the NPOESS downscale must be dealt with soon. The future degradation of the climate data system is a problem for most of the CCSP science questions. CLIMATE VARIABILITY AND CHANGE Much has been learned over the past few decades about the Earth’s climate system components, the interactions among them and their vari- ability, and how and why the climate system is changing. This improved understanding is continually translated into better models of climate system components and of the fully coupled system, and these models are being applied to important scientific and societal questions. For example, current models indicate that the observed global-, continental-, and ocean basin-

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5 EVALUATING PROGRESS OF THE U.S. CCSP scale temperature increases of the past several decades are outside the range of natural variability (IPCC, 2007). Observations underlie many of the advances in our understanding of the climate system. Ground-, ocean-, and space-based observations of key climate variables (e.g., surface and atmospheric temperature, precipitation, atmospheric moisture, clouds, winds, aerosols, sea level) provide insight on climate forcings (e.g., variations in solar output), processes (e.g., clouds, precipitation), and feedbacks (e.g., surface cover, albedo). Their compila- tion into long-term climate data records enables regional details of changes that are occurring in the global environment and their connections to hu- man activities to be discerned (Alverson and Baker, 2006; NRC, 2007a). Paleoclimate data sets enable assessment of longer-term variability within the climate system, and also place the global climate changes observed in recent decades within a longer context (NRC, 1990, 2006d). The climate variability and change research element plays an integra- tive role in the CCSP and is therefore central to the entire enterprise (CCSP, 2003). Specific objectives of the climate variability and change research element include reducing uncertainties and improving model predictions of climate variability and projections of change and determining their limits, assessing the likelihood of abrupt climate changes, examining how extreme events may be linked to climate variability and change, and formulating this knowledge in a way that can be integrated with non-climatic knowledge to support management and policy making. Progress Toward Answering the Research Questions Progress has been made in addressing the five questions under this research element, although accomplishments have been uneven. Better, longer, and more data sets have contributed to improved documentation and attribution of climate variability and change and to better understand- ing of many key climate processes (e.g., the global carbon cycle). However, as a result of ocean sampling limitations, evaluations of the decadal vari- ability in global heat content, salinity, and sea level changes can be made with only moderate confidence. Moreover, some processes (e.g., vertical ocean mixing, cloud feedbacks, the role of aerosols and ice sheet dynam- ics) are still relatively poorly understood. Although uncertainties remain in our understanding of climate processes and some processes need to be more fully represented (e.g., historical and likely future changes in land use; Feddema et al., 2005), state-of-the-art climate models are now able to reproduce many aspects of the climate of the past century, and simulations of the evolution of global surface temperature over the past millennium are consistent with paleoclimate reconstructions (IPCC, 2007). This achieve- ment improves confidence in future projections.

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5 PROGRESS TOWARD THE RESEARCH ELEMENTS Synthesis and assessment activities have also progressed (e.g., the release of Temperature Trends in the Lower Atmosphere; CCSP, 2006b), and some seasonal-to-interannual capabilities have been shared with stakeholders through the National Oceanic and Atmospheric Administration’s (NOAA’s) Regional Integrated Sciences and Assessments (RISA) program. However, although contributions to risk management and decision support have slowly increased, the individuals engaged have been few in number and many decisions have been made without strong scientific underpinnings. Q .1. To what extent can uncertainties in model projections due to climate system feedbacks be reduced? Investments in observation systems have paid off with improved under- standing and reduced uncertainties about feedbacks, although progress has been uneven and contributions to risk management and decision support have been inadequate. The response of global temperature to a given small forcing is proportional to the climate sensitivity. Feedback processes operat- ing in the atmosphere (e.g., changes in water vapor and cloud properties), ocean (e.g., efficiency of ocean mixing, changes in sea ice properties), and land (e.g., changes to surface cover, albedo, evapotranspiration, runoff, and biogeochemical cycles) collectively determine the climate sensitivity. The number and diversity of observations related to feedbacks have grown. For example, satellite data records over the past decade indicate that mass losses from the Greenland and West Antarctic ice sheets have contributed to global sea level rise (Velicogna and Wahr, 2006; Shepherd and Wingham, 2007) and that flow speed has been highly variable over short time inter- vals (a few years) for some Greenland outlet glaciers (Howat et al., 2007; Truffer and Fahnestock, 2007). Some key climate feedbacks (e.g., water vapor; see Trenberth, 2005) are better constrained, although less progress has been made on other im- portant feedbacks such as those involving ocean mixing (e.g., Wunsch and Ferrari, 2004), aerosol effects, and cloud processes. The initiation of climate process teams (CPTs) has encouraged much-needed collaboration between modelers and those involved in process- and observation-oriented research (see Chapter 5, “Modeling”), although CPT findings are just beginning to be incorporated into models (e.g., Danabasoglu et al., 2007). The availabil- ity of the suite of climate model simulations performed around the world to support the fourth IPCC assessment has resulted in a wider examination of climate system feedbacks, such as the sensitivity and response of polar systems to global climate change (e.g., Holland et al., 2006) and the pos- sible slowdown of the thermohaline circulation (Schmittner et al., 2005). However, scientific contributions to risk management and decision support have only begun to emerge.

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0 EVALUATING PROGRESS OF THE U.S. CCSP Q .2. How can predictions of climate variability and projections of climate change be improved, and what are the limits of their predictability? Good progress has been made in improving the quality of climate model simulations of variability and change, although uncertainties remain, especially on local and regional scales, and inadequate progress has been made in using model predictions to support decision making. The best cli- mate models encapsulate the current understanding of physical processes involved in the climate system, their interactions, and the performance of the system as a whole. They have been extensively tested and evaluated using observations and have become useful instruments for carrying out numerical climate experiments. For example, climate model simulations that account for changes in both natural and anthropogenic climate forc- ings have reliably shown that the observed warming of recent decades is a response to increased concentrations of greenhouse gases and sulfate aerosols in the atmosphere (IPCC, 2007). Attribution studies have also demonstrated that many of the observed changes in indicators of climate extremes consistent with warming (e.g., annual number of frost days, warm and cold days, warm and cold nights) have likely occurred as a result of increased anthropogenic forcing (e.g., Tebaldi et al., 2005). Despite significant advances, climate models are not perfect, and some models are better than others. Uncertainties remain because of shortcom- ings in our understanding of climate processes operating in the atmosphere, ocean, land, and cryosphere and how to best represent those processes in models (e.g., Rodwell and Palmer, 2007). For example, parameterizations of vertical ocean mixing are unrealistic and most coupled ocean-atmosphere global circulation models mix heat into the ocean too efficiently (Forest et al., 2007). Moreover, the global coupled climate system exhibits a wide range of physical and dynamical phenomena with associated physical, bio- logical, and chemical feedbacks that collectively result in a continuum of temporal and spatial variability. The accuracy of predictions on time scales from days or seasons to years, as well as long-standing systematic errors in climate models, is limited by our inadequate understanding and capability to simulate the complex, multiscale interactions intrinsic to atmospheric and oceanic fluid motions (e.g., Meehl et al., 2001) and to represent all other unresolved small-scale processes in the ocean and at the land surface. For example, decadal climate predictions may require the initialization of coupled models with estimates of the observed state of the climate system. This initialization requires an ongoing commitment and strengthening of the observing system (Trenberth et al., 2002, 2006; GCOS, 2003; NRC, 2007a). However, although some observations and data networks have improved (e.g., Gravity Recovery and Climate Experiment [GRACE], Argo

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1 PROGRESS TOWARD THE RESEARCH ELEMENTS ocean profiling floats1), others remain too sparse (e.g., atmospheric water vapor), poorly integrated with other essential observations (e.g., column ozone with temperature and water vapor), or in decline (e.g., Tropical Atmosphere Ocean [TAO] buoy array). Some observing systems suffer te- lemetry problems that have caused data to be lost (Trenberth et al., 2006). Ensembles of simulations that estimate the range of probable outcomes can be used to project climate change where uncertainty arises from limitations of the models and the emission scenarios used to represent the effects of human activity. Finally, use of climate model output by resource managers, planners, and decision makers remains limited, although exceptions exist. For ex- ample, a model of Lyme disease transmission, which simulates the effects of climate and other factors on disease risk, is being used by public health of- ficials to examine strategies for controlling tick populations (NRC, 2001c). However, the prediction value of such models is limited by uncertainties in the climate-disease relationship and the confounding influence of other factors. The California Department of Water Resources used a statistical analysis of VIC model outputs to obtain monthly average streamflows that could be used to estimate how reservoirs inflows would be affected by cli- mate change (CDWR, 2006). In general, however, resource managers need research results to be translated into different forms of information. Apart from programs such as RISA that have facilitated sharing of seasonal-to- interannual capabilities with stakeholders, few research results have been used to support risk management and decision making. Q .. What is the likelihood of abrupt changes in the climate system such as the collapse of the ocean thermohaline circulation, inception of a de- cades-long mega-drought, or rapid melting of the major ice sheets? CCSP management has been effective in marshaling the necessary re- sources to help answer this question. Good progress has been made in docu- menting abrupt climate change, but predictive capability remains low and the impact on decision making has been minimal. Good progress has been made in documenting abrupt climate change (e.g., mega-droughts) from proxy records such as lake cores (Vershuren et al., 2000) ice cores (Thomp- son et al., 2000, 2006), and integrated tree ring and observational data (Herweijer et al., 2006). Longer and more comprehensive data sets have revealed evidence of past abrupt changes that have the potential to occur in the future (Trenberth et al., 2004; Kerr, 2005). A 300-year long drought similar to the one that gripped East Africa 4,000 years ago (Thompson 1 Since 1999 the number of Argo floats has increased to 2,856 out of about 3,000 planned. See .

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 EVALUATING PROGRESS OF THE U.S. CCSP a very broad set of research questions and disciplines. The topics are some of the most fundamental in the arena of climate change as an environmental problem (as distinct from an interesting scientific puzzle), including how humans affect climate processes; how societies’ and people’s well-being is affected (positively and negatively) by changes in climate and by actions taken to mitigate or abate the effects of climate change; and how societies respond, cope, and adapt to climate-related impacts. The disciplines in- volved in the human contributions and responses research element include demography, psychology, geography and regional sciences, economics, an- thropology, political science, and sociology (CCSP, 2003). Decision support includes research on ways to get climate information used in decision making, the development of tools, and other activities similar to those traditionally associated with extension functions. It also includes research on and application of a systems engineering approach to decision making as exemplified by NASA’s program focusing on the use of data generated by its Earth Observation System in decision making. Although decision support activities often draw on results from human dimensions research, the latter is broader in scope and includes basic social sciences to understand and explain both anthropogenic causes of climate change and potential consequences of climate change for societies, cultures, political systems, and individuals. For example, research on how individu- als make decisions under great uncertainty will clearly have payoffs in the decision support arena. NSF’s program on Decision Making Under Uncer- tainty (DMUU), which has established five university centers, is a promising example of how human dimensions resources can be used to produce both basic and decision-driven science of great relevance (CCSP, 2007a; McNie et al., 2007; Sarewitz and Pielke, 2007). Finally, health effects research, as defined in the CCSP strategic plan, includes data collection, studies to understand potential effects of global environmental change on health, and assessment of the cumulative risk of negative effects of climate and environmental change on human health. A single interagency working group handles all three topics, and prog- ress and future plans for the three are reported together in Our Changing Planet. Combining management of human dimensions research and decision support tools deemphasizes the need for basic research in the social sciences throughout all the CCSP overarching goals. Moreover, the inclusion of re- search on the effects of ozone on health and systems engineering aspects of decision support resources in the budget makes it harder to determine the amount of resources being invested in human dimensions research. Con- sequently, to evaluate progress in the human contributions and responses research element, the committee had to obtain separate programmatic and budget information from the CCSP (see Appendix B). Research questions for the CCSP human contributions and responses

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 PROGRESS TOWARD THE RESEARCH ELEMENTS research element encompass the main areas of inquiry, including determin- ing the causes and consequences of human drivers of global climate change; understanding impacts and differential levels of vulnerability and adaptive capacity; and developing methods and capacities to improve societal deci- sion making under conditions of uncertainty and complexity. One of the questions also concerns understanding the human health effects of global climate change. Progress Toward Answering the Research Questions Important research in human dimensions has been carried out by a committed, if small, research community, despite the modest investment research thus far (about $25 million to $30 million per year; Appendix B). Significant findings have been published on both the human causes of global climate change and its impacts on societal well-being in the United States and other countries. In addition, a substantial portion of this research has been stakeholder driven and has resulted in positive interactions across the science-society divide, which not only created opportunities for decision- relevant research but also enhanced our understanding of opportunities and constraints for CCSP science-generated knowledge to affect decision making. The research on human dimensions appears to be of high quality, particularly work undertaken as part of NSF programs (e.g., DMUU cen- ters, Harvard knowledge systems for sustainable development project; see Cash, 2001; Cash et al., 2006; Clark and Holliday, 2006; van Kerkhoff and Lebel, 2006) and DOE’s program on integrated assessment modeling. The DOE program has coupled long-term support for major research programs at the Massachusetts Institute of Technology (MIT) and the Joint Global Change Research Institute (Pacific Northwest National Laboratory) with a diverse portfolio of smaller-scale research programs that focus on how natural science, economics, and other social science are integrated into policy models for climate change. However, many research gaps remain, and both the size of the human dimensions community and the level of available funding seem inadequate to carry out the research necessary to answer all of the research questions. Q .1. What are the magnitudes, interrelationships, and significance of pri- mary human drivers of and their potential impact on global environmental change? Progress in answering this research question has been inadequate. Our Changing Planet reports two projects that focus on the dynamics of human drivers of climate change (CCSP, 2005b). One study examined the relation- ship between income and the use of traditional fuels (e.g., firewood) versus

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0 EVALUATING PROGRESS OF THE U.S. CCSP commercial fuels for home heating and cooking in rural China, and the other study examined the role of household demography in decisions on land use, especially deforestation. Some research on human drivers has also been conducted outside the CCSP. However, synthesis and integration of results across human dimensions disciplines has been limited. For example, greenhouse gas emission scenarios continue to be based on simple models involving a few drivers (e.g., population, affluence, technological change). Recent studies are beginning to explore how these drivers affect each other and how they interact with other major social changes (e.g., urbanization, industrialization) and with environmental factors (e.g., tropical or temper- ate location) (York et al., 2003a, b; Rosa et al., 2004). Current understanding of the effects of human drivers on ecosystem change and, in turn, the effects of changes in ecosystem services on human well being is meager (Millennium Ecosystem Assessment, 2006). Changes in ecosystem services, including those caused by climate variability, are al- most always due to multiple, interacting drivers that work over time. These changes operate over multiple temporal, spatial, and governance scales and can also feed back to drivers. No existing conceptual framework captures the broad array of findings from the large bank of case studies presented in the Millennium Ecosystem Assessment. Q .2. What are the current and potential future impacts of global environ- mental variability and change on human welfare? What factors influence the capacity of human societies to respond to change and how can resilience be increased and vulnerability reduced? A few lines of research have shown promise, but considerably more effort and resources have to be expended to begin to answer this question. Although RISAs focus on climate variability and change, these regionally based programs have (1) produced valuable insights on institutional op- portunities and constraints on the use of climate knowledge by decision makers in different application sectors (e.g., water resources, fire and risk management, agriculture); (2) assessed vulnerabilities of a few groups of stakeholders; and (3) developed innovative methodologies to understand and manage the interaction between scientists and stakeholders (McNie et al., 2007). In addition, NOAA-sponsored research on the economics and human dimensions of climate variability and change has identified poten- tial impacts of climate-related phenomena on different sectors (e.g., water, agriculture, coastal areas). The same program has also sponsored a few projects focusing on vulnerability assessment and adaptation.7 Although a 7 Seeproject descriptions and a list of publications at .

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1 PROGRESS TOWARD THE RESEARCH ELEMENTS substantial portion of this research focused on climate variability, its find- ings have relevance to the transfer and diffusion of climate information to decision makers in different sectors working at smaller scales. A significant part of this research is being reported in synthesis and assessment product 5.3 (see Appendix A). Finally, a few assessments of vulnerability have been sponsored by DOE (Moss et al., 2001) and NSF (e.g., vulnerability of coastal communities; see Appendix B). However, these projects are minuscule relative to the magnitude of the question. Much more research is needed, especially in understanding the impacts of and adaptation to climate change across different sectors and geographical regions, mapping differential vulnerabilities, and designing interventions to build resilience. Similarly, progress on the economics of climate change has generally been inadequate, although a recent U.K. report was an important contribution to the field (Stern, 2007). Q .. How can the methods and capabilities for societal decision making under conditions of complexity and uncertainty about global environmental variability and change be enhanced? Overall, progress in advancing capabilities for decision making has been inadequate, but some significant research has been carried out to char- acterize uncertainty and complexity in the context of global climate change, to understand their impact on decision making and management, and to understand the links between producers and users of climate science. Four programs stand out as successes: DMUU centers, RISAs, DOE’s Integrated Assessment Program, and the Harvard knowledge systems project. Within the RISA programs, for example, some original data on potential impacts and governance responses (from both the public and the private sector) have been generated (e.g., Callahan et al., 1999; Hartmann et al., 2002; Pagano et al., 2002; Carbone and Dow, 2005; Jacobs et al., 2005; Lemos and Morehouse, 2005; O’Connor et al., 2005; CCSP, 2007a). However, RISA-generated data are mostly at the regional level and limited to sectors relevant at this scale, such as water in California or fisheries in the Pacific Northwest. Each of these four programs has made fair progress in understanding and characterizing uncertainties related to both physical and institutional processes affecting and being affected by global climate change. Some stud- ies have addressed the need to incorporate information from climate science into decision making and how to evaluate predictability and predictive capabilities of different physical and socioeconomic models, but this work is at an early stage. Finally, they have assessed and synthesized knowledge in their focus areas (e.g., Cash et al., 2003; CCSP, 2007a; McNie et al., 2007). In addition, DOE’s long-standing support of major integrated assess-

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2 EVALUATING PROGRESS OF THE U.S. CCSP ment projects has led to increased capabilities to conduct these assessments; major modeling teams at the Joint Global Change Research Institute and MIT, as well as a number of other researchers, are now working in this area. Some of this work is related to decision support and some to human dimensions research. However, the total output from these efforts has been low for the complexity and high levels of uncertainty that still characterize the physical processes causing global climate change and the magnitude of the potential impacts on socioeconomic and ecosystems (e.g., Millennium Environmental Assessment, 2006; Stern, 2007). Q .. What are the potential human health effects of global environmental change, and what climate, socioeconomic, and environmental information is needed to assess the cumulative risk to health from these effects? The vast bulk of this research program involves either health effects of ultraviolet radiation or satellite measurement of particulate matter con- centrations for health-related analysis. A few research projects focusing on the intersection of climate, health, and human dimensions have been car- ried out under the auspices of the Environmental Protection Agency and the Centers for Disease Control and Prevention (see Appendix B; CCSP, 2005b, pp. 131-132). For example, a health impacts assessment (Patz et al., 2000) examined the interactions between health and climate variability and change, and identified adaptation strategies. Opportunities and Threats A review of the CCSP strategic plan recommended accelerating efforts in human dimensions, economics, adaptation, and mitigation by strength- ening science plans and institutional support (NRC, 2004c). The inadequate progress of the human contributions and responses research element may reflect organizational problems within the agencies and the CCSP. Of par- ticular concern are the absence of social science leadership to guide the program and sufficient resources (dollars and people) to carry it out (see Table 2.1). Few agencies have programs dedicated to human contributions and responses, and CCSP funding devoted especially to human dimensions is significantly less than funding devoted to most of the other research ele- ments (Table 1.1). Human capacity may also be insufficient to carry out this work. The natural sciences may offer a successful model for building human dimensions capacity, especially programs to move young investigators into the arena and to support postdocs. The program could benefit from improved linkages to other programs, such as NSF’s biocomplexity program. Integration and enhanced support for human dimensions are especially critical given the potential for such

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 PROGRESS TOWARD THE RESEARCH ELEMENTS research to inform decision making and the management of climate impacts on human, sociopolitical, and ecological systems. If the quality and “us- ability” of the few projects already funded are any indication, investment in human dimensions not only is necessary, but may also be highly cost effective. Improvement of existing data sets and the collection of new data at suitable resolution would also speed progress in human dimensions. A major need is for data sets on both climate-related human activities and environmental data at the same spatial and temporal coverage and resolu- tion. Many relevant social data sets exist at useful levels of aggregation, but they have not been geocoded or are not available in spatial forms that are readily linked to environmental data (e.g., they are coded by political juris- dictions rather than spatial coordinates). For example, DOE has collected energy consumption data on residential, commercial, and industrial users since the 1970s, but most available data are aggregated at only the state or regional level and cannot be used to model the drivers of greenhouse gas emissions at higher resolutions. Data on property values are collected by jurisdictions around the country and they appear on maps, but not in forms that facilitate linkage to climate models and thus estimates of the economic consequences of possible future floods or storms on particular places. The use of such data sets in models would enable projections of greenhouse gas emissions that are based on analyses of the driving forces and their inter- actions, rather than on simplified assumptions about a few driving forces. It would also provide an empirical base for disaggregated analyses of the human consequences of climate variability and change and of the potential benefits of various adaptive and mitigative responses. Finally, future evaluations of progress would be greatly facilitated if the CCSP reported accomplishments on human dimensions research separately from accomplishments on decision support activities and health effects research. PRELIMINARY ASSESSMENT OF THE OVERARCHING GOALS: AN EXAMPLE As noted in Chapter 2, it should be possible to use results of the pre- liminary evaluation of research questions to assess the overarching goals. An example of how the evaluation could be conducted for focus area 1.4 of overarching goal 1 is given below. The committee first mapped the research questions and relevant cross-cutting issues to the focus areas (Box 4.1). The mapping proved challenging because the connections are not all laid out in the CCSP strategic plan, and each focus area is connected to several research questions and often to one or more cross-cutting issues. The scores

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 EVALUATING PROGRESS OF THE U.S. CCSP BOX 4.1 Links Between Overarching Goal 1 Focus Areas, Research Questions, and Cross-Cutting Issues Overarching Goal 1: Extend knowledge of the Earth’s past and present climate and environment, including its natural variability, and improve understanding of the causes of observed variability and change Focus 1.1. Better understand natural long-term cycles in climate (e.g., Pacific Decadal Variability, North Atlantic Oscillation) Associated research questions: 4.2, 5.1, 8.2, and 9.2 Focus 1.2. Improve and harness the capability to forecast El Niño-La Niña and other seasonal-to-interannual cycles of variability Associated research questions: 4.2, 5.2, and 9.2 Focus 1.3. Sharpen understanding of climate extremes through improved ob- servations, analysis, and modeling, and determine whether any changes in their frequency or intensity lie outside the range of natural variability Associated research questions: 4.3, 4.4, and 8.2 Focus 1.4. Increase confidence in the understanding of how and why climate has changed Associated research questions: 3.1, 3.2, 3.3, 4.4, 5.1, 5.2, 6.1, 6.2, 6.4, 7.1, 7.4, 8.1, and 9.1 Associated cross-cutting issues: 10.1, 10.2, and 10.3 (modeling) Focus 1.5. Expand observations and data and information system capabilities Associated research questions: 3.1, 3.2, 3.3, 3.5, 4.1, 4.5, 5.2, 5.4, 6.1, 6.2, 6.4, 7.1, 7.4, 8.1, and 8.2 Associated cross-cutting issues: 12 (observing) and 13 (data management) subgoals and comments on the relevant questions were then combined to make an overall evaluation. Focus Area 1.4 The twentieth century has witnessed major changes in both climate forcing terms (greenhouse gases, aerosols, land use and land cover, volcanic emissions of SO2) and climate (e.g., surface temperatures, atmospheric tem- peratures, ice and snow cover, mountain glaciers). Understanding how and why these changes occur is important for evaluating the human impact on climate and predicting future changes. Thus, focus area 1.4 is a key com- ponent of the CCSP and involves several research questions. Focus area 1.4 is addressed by five research elements—including atmospheric composition, climate variability and change, water cycle, land use and land cover change, and human contributions and responses—and the modeling cross-cutting issue. It has two parts, which are evaluated separately below.

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5 PROGRESS TOWARD THE RESEARCH ELEMENTS How Has Climate Changed? Good progress has been made in this area. For example, the IPCC (2007) concludes that “warming of the climate system is unequivocal.” Research conducted under the CCSP, including the synthesis and assessment report on atmospheric temperature trends, played an important role in the IPCC’s finding. However, continued progress is seriously threatened by the loss of climate instruments on NPOESS and other satellites. The research part of this topic is covered under questions 4.2 and 4.4 of the climate variability and change research element. Sustained investments in observing systems and models have led to advances in understanding ocean processes and several natural forcing terms (e.g., solar insulation, volcanic emissions), as well as the relationship between climate variability and change, droughts, and wildfires. A limited number of paleoclimate records needed to advance understanding and improve predictions are also available. In addition, three synthesis and assessment products (1.1, 1.2, and 1.3) are relevant to this focus area. Synthesis and assessment product 1.1 (tem- perature trends) largely resolved the discrepancy between surface observa- tions of surface warming and satellite observations of atmospheric warming (CCSP, 2006b). The two other products have not yet been published (see Appendix A). Why Has Climate Changed? Major improvements have been made in quantifying the anthropogenic forcing terms (i.e., radiative forcing due to greenhouse gases, aerosol forc- ing, land use albedo forcing). For example, the IPCC (2007) concludes that the “globally averaged net effect of human activities since 1750 has been one of warming with a radiative forcing of +1.6 [+0.6 to +2.4] Wm–2.” However, large uncertainties remain in the magnitude of emissions of aero- sols, aerosol-cloud interactions, and the importance of tropospheric ozone forcing. Internal variability in the coupled land-ocean-atmosphere system, changes in natural climate forcing terms (solar insolation and volcanic emissions), and anthropogenic influences (changes in greenhouse gas emis- sions, aerosols, and land use and land cover) contribute to climate changes. Our understanding of these processes has improved significantly over the last few decades, fueled by the synthesis of different types of observations (satellite, aircraft, ship, buoy, land surface) and the integration of observa- tions and laboratory experiments. In addition, models (e.g., coupled ocean- atmosphere-land climate models, chemical transport models, carbon cycle models) have played a fundamental role in sorting out the various forcing factors that influenced the observed changes. Changes in climate forcing are covered in research questions 3.1, 3.2, 3.3, 6.1, 6.2, 7.1, 7.4, and 9.1. The

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 EVALUATING PROGRESS OF THE U.S. CCSP effects of climate change feedbacks on forcing are covered in questions 5.2, 6.4, and 8.1. Fundamental weaknesses still exist in the following areas: • Regional climate changes. Concerted efforts to quantify the impact of human activities on North American climate change and its subsequent consequences for agriculture, the water budget, and health have been lim- ited since the last major assessment of climate change impacts in the late 1990s (National Assessment Synthesis Team, 2000). • Role of cloud feedback in climate change. Changes in water vapor, clouds, and precipitation in response to changes in climate forcing and cli- mate change can have major feedback effects. Aerosol-cloud-precipitation feedbacks are also part of this issue. The effect of aerosols in inhibiting cloud formation has been measured, but large uncertainties remain about the emission sources of elemental and organic carbon, the indirect effect of aerosols on climate, and the importance of aerosol solar heating of the atmosphere on climate. • Feedback processes between the physical, chemical, and biologi- cal parts of the climate system. Progress in understanding these feedback processes, which may also have influenced the observed changes, has been inadequate. • Climate-societal interactions. Progress has been inadequate in the development of a quantitative understanding of how societal behavior and choices affect the environment and how societies in turn are affected by the environment. Good progress has been made in mapping land cover change, but these studies have been limited by difficulty in obtaining relevant socioeconomic data. With the exception of advances in land use change and decision mak- ing under uncertainty, inadequate progress has been made on understanding the human drivers of climate change. Ecosystems influence atmospheric composition of greenhouse gases, aerosol precursors, and absorption and reflection of solar radiation at the surface. However, research efforts to date have focused on understanding changes that will occur in ecosystems as a result of climate change. Scientific questions regarding the response of the climate system to nat- ural and anthropogenic forcing cannot be addressed with traditional physi- cal climate models (e.g., those that do not include interactive chemistry, the carbon cycle, or interactive aerosol models). Consequently, significant efforts have been made to extend physical models to include the interac- tions of climate with biogeochemistry, atmospheric chemistry, ecosystems, glaciers and ice sheets, and anthropogenic environmental change. The types of measurements and models needed to obtain a more comprehensive un- derstanding of feedbacks for terrestrial and marine ecosystems are still be-

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 PROGRESS TOWARD THE RESEARCH ELEMENTS ing defined. Finally, U.S. underinvestment in computing power has limited progress in accurately representing key climate processes and feedbacks. Overall, the committee found that a fair amount of progress has been made on focus area 1.4. Slightly greater advances have been made in under- standing how climate has changed than why it has changed. These advances have been driven largely by the availability of a wide range of data from satellite and in situ networks, which have significantly improved our ability to represent physical quantities. Understanding of the forcing factors that affect climate—and vice versa—has progressed steadily, with the greatest gains in atmospheric composition and, to a lesser extent, the water cycle. Inadequate progress has been made in understanding ecosystem or human feedbacks and developing coupled models capable of addressing natural and anthropogenic forcing.

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