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2013 | Buch

Climate Science for Serving Society

Research, Modeling and Prediction Priorities

herausgegeben von: Ghassem R. Asrar, James W. Hurrell

Verlag: Springer Netherlands

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This volume offers a comprehensive survey and a close analysis of efforts to develop actionable climate information in support of vital decisions for climate adaptation, risk management and policy. Arising from submissions and discussion at the 2011 Open Science Conference (OSC) of the World Climate Research Program (WCRP), the book addresses research and intellectual challenges which span the full range of Program activities.

Inhaltsverzeichnis

Frontmatter
The World Climate Research Program Strategy and Priorities: Next Decade
Abstract
In this chapter an overview of the research planning and priorities of the World Climate Research Program (WCRP) over the next decade is provided. The research, modeling and prediction plans are significantly shaped by the major sponsors of the WCRP, as well as by its international network of scientists and stakeholders. However, major input into the planning process was also derived from sessions and discussions among the more than 1,900 scientists who attended the WCRP Open Science Conference (OSC) in October 2011. This monograph is comprised of position papers emanating from the OSC. They address many of the overall research and intellectual challenges across the WCRP spectrum of activities. A brief overview of these papers is given.
Ghassem R. Asrar, James W. Hurrell, Antonio J. Busalacchi
Challenges of a Sustained Climate Observing System
Abstract
Observations of planet Earth and especially all climate system components and forcings are increasingly needed for planning and informed decision making related to climate services in the broadest sense. Although significant progress has been made, much more remains to be done before a fully functional and dependable climate observing system exists. Observations are needed on spatial scales from local to global, and all time scales, especially to understand and document changes in extreme events. Climate change caused by human activities adds a new dimension and a vital imperative: to acquire climate observations of sufficient quality and coverage, and analyze them into products for multiple purposes to inform decisions for mitigation, adaptation, assessing vulnerability and impacts, possible geo-engineering, and predicting climate variability and change and their consequences. A major challenge is to adequately deal with the continually changing observing system, especially from satellites and other remote sensing platforms such as in the ocean, in order to provide a continuous climate record. Even with new computational tools, challenges remain to provide adequate analysis, processing, meta-data, archival, access, and management of the resulting data and the data products. As volumes of data continue to grow, so do the challenges of distilling information to allow us to understand what is happening and why, and what the implications are for the future. The case is compelling that prompt coordinated international actions are essential to provide for information-based actions and decisions related to climate variability and change.
Kevin E. Trenberth, Richard A. Anthes, Alan Belward, Otis B. Brown, Ted Habermann, Thomas R. Karl, Steve Running, Barbara Ryan, Michael Tanner, Bruce Wielicki
On the Reprocessing and Reanalysis of Observations for Climate
Abstract
The long observational record is critical to our understanding of the Earth’s climate, but most observing systems were not developed with a climate objective in mind. As a result, tremendous efforts have gone into assessing and reprocessing the data records to improve their usefulness in climate studies. The purpose of this paper is to both review recent progress in reprocessing and reanalyzing observations, and summarize the challenges that must be overcome in order to improve our understanding of climate and variability. Reprocessing improves data quality through more scrutiny and improved retrieval techniques for individual observing systems, while reanalysis merges many disparate observations with models through data assimilation, yet both aim to provide a climatology of Earth processes. Many challenges remain, such as tracking the improvement of processing algorithms and limited spatial coverage. Reanalyses have fostered significant research, yet reliable global trends in many physical fields are not yet attainable, despite significant advances in data assimilation and numerical modeling. Oceanic reanalyses have made significant advances in recent years, but will only be discussed here in terms of progress toward integrated Earth system analyses. Climate data sets are generally adequate for process studies and large-scale climate variability. Communication of the strengths, limitations and uncertainties of reprocessed observations and reanalysis data, not only among the community of developers, but also with the extended research community, including the new generations of researchers and the decision makers is crucial for further advancement of the observational data records. It must be emphasized that careful investigation of the data and processing methods are required to use the observations appropriately.
Michael G. Bosilovich, John Kennedy, Dick Dee, Rob Allan, Alan O’Neill
Climate Processes: Clouds, Aerosols and Dynamics
Abstract
Physical processes not well resolved by climate models continue to limit confidence in detailed predictions of climate change. The representation of cloud and convection-related processes dominates the model spread in global climate sensitivity, and affects the simulation of important aspects of the present-day climate especially in the tropics. Uncertainty in aerosol radiative effects complicates the interpretation of climate changes in the observational and paleoclimate records, in particular limiting our ability to infer climate sensitivity. Dynamical uncertainties, notably those involving teleconnections and troposphere-stratosphere interaction, also affect simulation of regional climate change especially at high latitudes. In response, targeted field programs, new satellite capabilities, and new computational approaches are promoting progress on these problems. Advances include recognition of the likely importance of non-greenhouse gas forcings in driving recent trends in the general circulation, compensating interactions and emergent phenomena in aerosol-cloud-dynamical systems, and the climatic importance of cumulus entrainment. Continued progress will require, among other things, more integrative analysis of key processes across scales, recognizing the complexity at the local level but also the constraints and possible buffering operating at larger (system) scales.
Steven C. Sherwood, M. Joan Alexander, Andy R. Brown, Norm A. McFarlane, Edwin P. Gerber, Graham Feingold, Adam A. Scaife, Wojciech W. Grabowski
Aerosol Cloud-Mediated Radiative Forcing: Highly Uncertain and Opposite Effects from Shallow and Deep Clouds
Abstract
Aerosol cloud-mediated radiative forcing, commonly known as the aerosol indirect effect (AIE), dominates the uncertainty in our ability to quantify anthropogenic climate forcing and respectively the climate sensitivity. This uncertainty can be appreciated based on the state of our understanding as presented in this chapter.
Adding aerosols to low clouds generally causes negative radiative forcing by three main mechanisms: redistributing the same cloud water in larger number of smaller drops, adding more cloud water, and increasing the cloud cover. Aerosols affect these components sometimes in harmony but more often in opposite ways. These processes can be highly non-linear, especially in precipitating clouds in which added aerosol can inhibit rain. There is probably little overall sensitivity in most clouds but hyper sensitivity in some, where the processes become highly nonlinear with positive feedbacks, causing changes of cloud regimes in marine stratocumulus under anticyclones. This leads to a complicated and uneven AIE. Process models at high resolution (LES) have reached the stage that they can capture much of this complicated behavior of shallow clouds. The implementation of the processes of cloud aerosol interactions into GCMs is rudimentary due to severe computational limitations and the current state of cloud and aerosol parameterizations, but intense research efforts aimed at improving the realism of cloud-aerosol interaction in GCMs are underway.
Aerosols added to deep clouds generally produce an additional component of positive radiative forcing due to cloud top cooling, expanding, and detraining vapor to the upper troposphere and lower stratosphere. The level of scientific understanding of the AIE on deep clouds is even lower than for the shallow clouds, as mixed phase and ice processes play an important role. Respectively, the parameterization of these processes for GCMs is further away than for the low clouds.
Crucially, the AIE of both shallow and deep clouds must be considered for quantifying anthropogenic climate forcing and inferring climate sensitivity from observations.
While our objective is reducing the uncertainty, it appears that the recently acquired additional knowledge actually increased the uncertainty range of the AIE, as we learn of additional effects that should be quantified.
Daniel Rosenfeld, Robert Wood, Leo J. Donner, Steven C. Sherwood
Improving Understanding of the Global Hydrologic Cycle
Observation and Analysis of the Climate System: The Global Water Cycle
Abstract
Understanding the complexity of the hydrological cycle is central to understanding a wide range of other planetary geological, atmospheric, chemical, and physical processes. Water is also central to other core economic, social, and political issues such as poverty, health, hunger, environmental sustainability, conflict, and economic prosperity. As society seeks to meet demands for goods and services for a growing population, we must improve our understanding of the fundamental science of the hydrological cycle, its links with related global processes, and the role it plays in ecological and societal well-being. At the same time, human influences on the character and dynamics of the water cycle are growing rapidly. Central to solving these challenges is the need to improve our systems for managing, sharing, and analyzing all kinds of water data, and our ability to model and forecast aspects of both the hydrological cycle and the systems we put in place to manage human demands for water. We need to improve our understanding of each of the components of the hydrological water balance at all scales, and to understand the spatial and temporal variability in the components of the water cycle. This chapter provides a short summary of current WCRP efforts and addresses four primary research challenges:
1.
The collection of more comprehensive data and information on all aspects of the hydrologic cycle and human uses of water, at enhanced spatial and temporal resolution and increased precision;
 
2.
Improved management and distribution of these data;
 
3.
Improved representation of the anthropogenic manipulations of the water cycle in the coupled land-atmosphere-ocean models used to forecast climate variations and change at both seasonal to interannual, and decade to century, time scales; and
 
4.
Expanded research at the intersection of hydrological sciences and the technical, social, economic, and political aspects of freshwater management and use.
 
Peter H. Gleick, Heather Cooley, James S. Famiglietti, Dennis P. Lettenmaier, Taikan Oki, Charles J. Vörösmarty, Eric F. Wood
Land Use and Land Cover Changes and Their Impacts on Hydroclimate, Ecosystems and Society
Abstract
This chapter presents recent advances in the understanding of the effect of land cover/land use changes on the hydrologic cycle, and identifies current gaps in the knowledge needed for useful decision-making and water resource management. Research achievements within a framework of Earth System Models (ESM) are introduced, and research needs and future challenges are identified. Land surface provides the lower boundary condition to the atmosphere over continents by controlling the fluxes of momentum, heat, water, and materials such as carbon. In turn, land surface conditions are substantially influenced by atmospheric conditions on various temporal scales. As such, a land-atmosphere coupled system is established through biogeochemical feedbacks. Current land surface models exhibit a wide variety of responses to the same forcings, suggesting the need for increased research at the land-atmosphere interface. Indeed, all Earth System Models require the inclusion and validation of the processes that pertain to the biogeochemical feedbacks. Anthropogenic activities that result in land use and land cover changes affect the land surface characteristics and consequently the land-atmosphere feedbacks and coupling strength. Therefore, human activities play a role in the land-atmosphere coupling system, and thus, in the climate system. Water is essential to societal needs that require the construction of reservoirs, extraction of ground water, irrigation, changes in land use, urbanization among many other influences. The extent and sustainability of those interferences in the natural system remains to be assessed at global scales.
Taikan Oki, Eleanor M. Blyth, Ernesto Hugo Berbery, Domingo Alcaraz-Segura
Prediction from Weeks to Decades
Abstract
This white paper is a synthesis of several recent workshops, reports and published literature on monthly to decadal climate prediction. The intent is to document: (i) the scientific basis for prediction from weeks to decades; (ii) current capabilities; and (iii) outstanding challenges. In terms of the scientific basis we described the various sources of predictability, e.g., the Madden Jullian Ocillation (MJO); Sudden Stratospheric Warmings; Annular Modes; El Niño and the Southern Oscillation (ENSO); Indian Ocean Dipole (IOD); Atlantic “Niño;” Atlantic gradient pattern; snow cover anomalies, soil moisture anomalies; sea-ice anomalies; Pacific Decadal Variability (PDV); Atlantic Multi-Decadal Variability (AMV); trend among others. Some of the outstanding challenges include how to evaluate and validate prediction systems, how to improve models and prediction systems (e.g., observations, data assimilation systems, ensemble strategies), the development of seamless prediction systems.
Ben Kirtman, David Anderson, Gilbert Brunet, In-Sik Kang, Adam A. Scaife, Doug Smith
Assessing the Reliability of Climate Models, CMIP5
Abstract
In spite of the yet incomplete subsample of the 5th phase of the Coupled Model Intercomparison Project (CMIP5) model ensemble to date, evaluation of these models is underway. Novel diagnostics and analysis methods are being utilized in order to explore the skill of particular processes, the degree to which models have improved since CMIP3, and particular features of the hindcasts, decadal and centennial projections. These assessments strongly benefit from the increasing availability of state-of-the-art data sets and model output processing techniques. Also paleo-climate analysis proves to be useful for demonstrating the ability of models to simulate climate conditions that are different from present day. The existence of an increasingly wide ensemble of model simulations re-emphasizes the need to carefully consider the implications of model spread. Disparity between projected results does imply that model uncertainty exists, but not necessarily reflects a true estimate of this uncertainty. Projections generated by models with a similar origin or utilizing parameter perturbation techniques generally show more mutual agreement than models with different development histories. Weighting results from different models is a potentially useful technique to improve projections, if the purpose of the weighting is clearly identified. However, there is yet no consensus in the community on how to best achieve this.
These findings, discussed at the session “Assessing the reliability of climate models: CMIP5” of the World Climate Research Program (WCRP) Open Science Conference (OSC), illustrate the need for comprehensive and coordinated model evaluation and data collection. The role that WCRP can play in this coordination is summarized at the end of this chapter.
Bart van den Hurk, Pascale Braconnot, Veronika Eyring, Pierre Friedlingstein, Peter Gleckler, Reto Knutti, Joao Teixeira
Changes in Variability Associated with Climate Change
Abstract
In this paper, we briefly discuss changes in large-scale oscillations such as the El Nino/Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), and the northern and southern annular modes (NAM and SAM), changes in the polar and tropical troposphere, and interactions between the stratosphere and troposphere in a changing climate. We consider both changes in variability as well as trends in the mean state. We conclude, that to fully understand how modes of variability will change in a changing climate, we need additional analysis of observations, both paleo and present day, and a solid fundamental understanding of mechanisms. Understanding of mechanisms necessarily requires use of models, ranging from simple to complex. Such models need to be fully coupled, between atmosphere and ocean, and need to include a fully resolved middle atmosphere as well.
Karen H. Rosenlof, Laurent Terray, Clara Deser, Amy Clement, Hugues Goosse, Sean Davis
Understanding and Predicting Climate Variability and Change at Monsoon Regions
Abstract
The chapter highlights selected scientific advances made under WCRP leadership in understanding climate variability and predictability at regional scales with emphasis on the monsoon regions. They are mainly related to a better understanding of the physical processes related to the ocean-land-atmosphere interaction that characterize the monsoon variability as well as to a better knowledge of the sources of climate predictability. The chapter also highlights a number of challenges that are considered crucial to improving the ability to simulate and thereby predict regional climate variability. The representation of multi-scale convection and its interaction with coupled modes of tropical variability (where coupling refers both to ocean-atmosphere and/or land-atmosphere coupling) remains the leading problem to be addressed in all aspects of monsoon simulations (intraseasonal to decadal prediction, and to climate change).
Systematic errors in the simulation of the mean annual and diurnal cycles continue to be critical issues that reflect fundamental deficiencies in the representation of moist physics and atmosphere/land/ocean coupling. These errors do not appear to be remedied by simple model resolution increases, and they are likely a major impediment to improving the skill of monsoon forecasts at all time scales. Other processes, however, can also play an important role in climate simulation at regional levels. The influence of land cover change requires better quantification. Likewise, aerosol loading resulting from biomass burning, urban activities and land use changes due to agriculture are potentially important climate forcings requiring better understanding and representation in models. More work is also required to elucidate mechanisms that give rise to intraseasonal variability. On longer timescales an improved understanding of interannual to decadal monsoon variability and predictability is required to better understand, attribute and simulate near-term climate change and to assess the potential for interannual and longer monsoon prediction.
A need is found to strengthen the links between model evaluation at the applications level and process-oriented refinement of model formulation. Further work is required to develop and sustain effective communication among the observation, model user, and model development communities, as well as between the academic and “operational” model development communities. More research and investment is needed to translate climate data into actionable information at the regional and local scales required for decisions.
Carolina Vera, William Gutowski, Carlos R. Mechoso, B. N. Goswami, Chris C. Reason, Chris D. Thorncroft, Jose Antonio Marengo, Bruce Hewitson, Harry Hendon, Colin Jones, Piero Lionello
Attribution of Weather and Climate-Related Events
Abstract
Unusual or extreme weather and climate-related events are of great public concern and interest, yet there are often conflicting messages from scientists about whether such events can be linked to climate change. There is clear evidence that climate has changed as a result of human-induced greenhouse gas emissions, and that across the globe some aspects of extremes have changed as a result. But this does not imply that human influence has significantly altered the probability of occurrence or risk of every recently observed weather or climate-related event, or that such events are likely to become significantly more or less frequent in the future. Conversely, it is sometimes stated that it is impossible to attribute any individual weather or climate-related event to a particular cause. Such a statement can be interpreted to mean that human-induced climate change could never be shown to be at least partly responsible for any specific weather event, either the probability of its occurrence or its magnitude. There is clear evidence from recent case studies that individual event attribution is a feasible, if challenging, undertaking.
We propose a way forward, through the development of carefully calibrated physically-based assessments of observed weather and climate-related events, to identify changed risk of such events attributable to particular factors including estimating the contributions of factors to event magnitude. Although such event-specific assessments have so far only been attempted for a relatively small number of specific cases, we describe research under way, coordinated as part of the international Attribution of Climate-related Events (ACE) initiative, to develop the science needed to better respond to the demand for timely, objective, and authoritative explanations of extreme events. The paper considers the necessary components of a prospective event attribution system, reviews some specific case studies made to date (Autumn 2000 UK floods, summer 2003 European heatwave, annual 2008 cool US temperatures, July 2010 Western Russia heatwave) and discusses the challenges involved in developing systems to provide regularly updated and reliable attribution assessments of unusual or extreme weather and climate-related events.
Peter A. Stott, Myles Allen, Nikolaos Christidis, Randall M. Dole, Martin Hoerling, Chris Huntingford, Pardeep Pall, Judith Perlwitz, Dáithí Stone
Climate Extremes: Challenges in Estimating and Understanding Recent Changes in the Frequency and Intensity of Extreme Climate and Weather Events
Abstract
This paper focuses primarily on extremes in the historical instrumental period. We consider a range of phenomena, including temperature and precipitation extremes, tropical and extra-tropical storms, hydrological extremes, and transient extreme sea-level events. We also discuss the extent to which detection and attribution research has been able to link observed changes to external forcing of the climate system. Robust results are available that detect and often attribute changes in frequency and intensity of temperature extremes to external forcing. There is also some evidence that on a global scale, precipitation extremes have intensified due to forcing. However, robustly detecting and attributing forced changes in other important extremes, such as tropical and extratropical storms or drought remains challenging.
In our review we find that there are multiple challenges that constrain advances in research on extremes. These include the state of the historical observational record, limitations in the statistical and other tools that are used for analyzing observed changes in extremes, limitations in the understanding of the processes that are involved in the production of extreme events, and in the ability to describe the natural variability of extremes with models and other tools.
Despite these challenges, it is clear that enormous progress is being made in the quest to improve the understanding of extreme events, and ultimately, to produce predictive products that will help society to manage the associated risks.
Francis W. Zwiers, Lisa V. Alexander, Gabriele C. Hegerl, Thomas R. Knutson, James P. Kossin, Phillippe Naveau, Neville Nicholls, Christoph Schär, Sonia I. Seneviratne, Xuebin Zhang
Carbon Dioxide and Climate: Perspectives on a Scientific Assessment
Abstract
Many of the findings of the Charney Report on CO2-induced climate change published in 1979 are still valid, even after 30 additional years of climate research and observations. This paper considers the reasons why the report was so prescient, and assesses the progress achieved since its publication. We suggest that emphasis on the importance of physical understanding gained through the use of theory and simple models, both in isolation and as an aid in the interpretation of the results of General Circulation Models, provided much of the authors’ insight at the time. Increased emphasis on these aspects of research is likely to continue to be productive in the future, and even to constitute one of the most efficient routes towards improved climate change assessments.
Sandrine Bony, Bjorn Stevens, Isaac H. Held, John F. Mitchell, Jean-Louis Dufresne, Kerry A. Emanuel, Pierre Friedlingstein, Stephen Griffies, Catherine Senior
Atmospheric Composition, Irreversible Climate Change, and Mitigation Policy
Abstract
The Earth’s atmosphere is changing due to anthropogenic increases of gases and aerosols that influence the planetary energy budget. Policy has long been challenged to ensure that instruments such as the Kyoto Protocol or carbon trading deal with the wide range of lifetimes of these radiative forcing agents. Recent research has sharpened scientific understanding of how climate system time scales interact with the time scales of the forcing agents themselves. This has led to an improved understanding of metrics used to compare different forcing agents, and has prompted consideration of new metrics such as cumulative carbon. Research has also clarified the understanding that short-lived forcing agents can “trim the peak” of coming climate change, while long-lived agents, especially carbon dioxide, will be responsible for at least a millennium of elevated temperatures and altered climate, even if emissions were to cease. We suggest that these vastly differing characteristics imply that a single basket for trading among forcing agents is incompatible with current scientific understanding.
Susan Solomon, Raymond T. Pierrehumbert, Damon Matthews, John S. Daniel, Pierre Friedlingstein
Building Adaptive Capacity to Climate Change in Less Developed Countries
Abstract
This paper focuses on the relevance of adaptive capacity in the context of the increasing certainty that climate change impacts will affect human populations and different social groups substantially and differentially. Developing and building adaptive capacity requires a combination of interventions that address not only climate-related risks (specific capacities) but also the structural deficits (lack of income, education, health, political power, etc.—generic capacities) that shape vulnerability. We argue that bolstering both generic and specific adaptive capacities, with careful attention to minimizing the potential tensions between these two types of capacities, can help vulnerable groups maintain their ability to address risks in the long run at the same time as they respond effectively to short term climate impacts. We examine the relationship between generic and specific capacities, taking into consideration that they are not always positively related. We then propose a conceptual model describing positive and negative feedbacks between the two.
Maria Carmen Lemos, Arun Agrawal, Hallie Eakin, Don R. Nelson, Nathan L. Engle, Owen Johns
A Climate and Health Partnership to Inform the Prevention and Control of Meningoccocal Meningitis in Sub-Saharan Africa: The MERIT Initiative
Abstract
Many human diseases are climate-sensitive: climate acting as an important driver of spatial and seasonal patterns, year-to-year variations (including epidemics), and longer-term trends. Although climate is only one of the many drivers of both infectious and non-infectious disease, public health policy makers and practitioners are increasingly concerned about the potential impact of climate change on the health of populations.
The MERIT Initiative was launched in 2007 to provide a platform for enabling health specialists (public health specialists, epidemiologists, immunologists, microbiologists, demographers, etc.) and climate and environment specialists to work together to help solve a pressing health problem. The main objective of the initiative is to address meningococcal meningitis epidemics in Africa in the context of perceived environmental, biological, economic and demographic influences. The effort is designed to create new knowledge that can be used to improve the current (reactive) and future (preventive) vaccination strategies.
Preliminary results of this research to policy and practice consortium have advanced the understanding of how climate-related information can be tailored to inform and, where possible, strengthen public health decisions. Specifically, the MERIT experience to date indicates new evidence on the contribution that climate and environment make to the spatio-temporal distribution of meningococcal meningitis and demonstrates a multi-sectoral strategic approach to the creation of evidence, together with the development of a cumulative knowledge base. The MERIT Initiative is establishing an effective means for the dissemination of new knowledge and provides a platform to facilitate access to this knowledge by public health practitioners. These developments, along with an increase in the uptake of evidence in both policy and practice have the potential to impact health outcomes in vulnerable at-risk populations in Africa’s Meningitis Belt.
The collaborative partnership model of MERIT provides an innovative framework to support public health preparedness and control strategies for climate sensitive diseases. Public health decision-makers have been willing to explore unfamiliar territory and opportunities for improving well-established control strategies by leveraging new knowledge and expertise from other disciplinary communities including climate and environmental researchers. Equally important have been the investments made by a multi-disciplinary research and practice community to adapt research projects in line with the evolving public health strategy across the Meningitis Belt. The lessons learned from the MERIT project offer valuable input and new ideas for improving global public health strategies for other climate and environmentally sensitive epidemic prone diseases.
Madeleine C. Thomson, E. Firth, M. Jancloes, A. Mihretie, M. Onoda, S. Nickovic, H. Broutin, S. Sow, W. Perea, E. Bertherat, S. Hugonnet
Metadaten
Titel
Climate Science for Serving Society
herausgegeben von
Ghassem R. Asrar
James W. Hurrell
Copyright-Jahr
2013
Verlag
Springer Netherlands
Electronic ISBN
978-94-007-6692-1
Print ISBN
978-94-007-6691-4
DOI
https://doi.org/10.1007/978-94-007-6692-1