121-140 of 274 Results

Article

As climate change becomes an increasingly serious problem, mass media are tasked with educating the public. Documentary films and television shows (also called “edutainment”) have been used for decades to communicate about the natural world so that the public may hopefully become informed about science in a simplified, easy-to-understand way. Although producers ostensibly create environmental documentaries in order to inform and/or advocate, theory development and empirical research is limited and insufficient in explaining how this genre influences audiences and why this genre may or may not be an effective means of science communication. Environmental documentaries have the potential to deeply impact audiences because these films promote learning while viewers are entertained, because engagement with the documentary narrative (story) can overcome biases such as politically driven motivated reasoning (conforming new evidence to existing beliefs) and can leverage biases such as the tendency to rely on affect (emotions) when estimating risks. Documentary storytelling can also enhance learning by connecting the causes and consequences of climate change in a sequential narrative. Climate change is a highly contentious political issue, which is reflected in the diversity of viewpoints found in climate change documentaries despite scientific consensus about the issue. While many of these films serve an educational purpose, others are geared toward advocacy. These advocacy programs aim to mobilize value-congruent audiences to engage in personal and collective action and/or to demand policy change. However, people prefer messages that align with their preexisting values, and so the belief disparity between climate change advocates and deniers grows with increasing media exposure as audiences with different beliefs watch and receive climate change messages in very different ways. Filmmakers and scientists must focus future efforts on creating visually engaging narratives within documentaries to promote both education and advocacy to diverse audiences.

Article

Rasmus Benestad

What are the local consequences of a global climate change? This question is important for proper handling of risks associated with weather and climate. It also tacitly assumes that there is a systematic link between conditions taking place on a global scale and local effects. It is the utilization of the dependency of local climate on the global picture that is the backbone of downscaling; however, it is perhaps easiest to explain the concept of downscaling in climate research if we start asking why it is necessary. Global climate models are our best tools for computing future temperature, wind, and precipitation (or other climatological variables), but their limitations do not let them calculate local details for these quantities. It is simply not adequate to interpolate from model results. However, the models are able to predict large-scale features, such as circulation patterns, El Niño Southern Oscillation (ENSO), and the global mean temperature. The local temperature and precipitation are nevertheless related to conditions taking place over a larger surrounding region as well as local geographical features (also true, in general, for variables connected to weather/climate). This, of course, also applies to other weather elements. Downscaling makes use of systematic dependencies between local conditions and large-scale ambient phenomena in addition to including information about the effect of the local geography on the local climate. The application of downscaling can involve several different approaches. This article will discuss various downscaling strategies and methods and will elaborate on their rationale, assumptions, strengths, and weaknesses. One important issue is the presence of spontaneous natural year-to-year variations that are not necessarily directly related to the global state, but are internally generated and superimposed on the long-term climate change. These variations typically involve phenomena such as ENSO, the North Atlantic Oscillation (NAO), and the Southeast Asian monsoon, which are nonlinear and non-deterministic. We cannot predict the exact evolution of non-deterministic natural variations beyond a short time horizon. It is possible nevertheless to estimate probabilities for their future state based, for instance, on projections with models run many times with slightly different set-up, and thereby to get some information about the likelihood of future outcomes. When it comes to downscaling and predicting regional and local climate, it is important to use many global climate model predictions. Another important point is to apply proper validation to make sure the models give skillful predictions. For some downscaling approaches such as regional climate models, there usually is a need for bias adjustment due to model imperfections. This means the downscaling doesn’t get the right answer for the right reason. Some of the explanations for the presence of biases in the results may be different parameterization schemes in the driving global and the nested regional models. A final underlying question is: What can we learn from downscaling? The context for the analysis is important, as downscaling is often used to find answers to some (implicit) question and can be a means of extracting most of the relevant information concerning the local climate. It is also important to include discussions about uncertainty, model skill or shortcomings, model validation, and skill scores.

Article

S.C. Pryor and A.N. Hahmann

Winds within the atmospheric boundary layer (i.e., near to Earth’s surface) vary across a range of scales from a few meters and sub-second timescales (i.e., the scales of turbulent motions) to extremely large and long-period phenomena (i.e., the primary circulation patterns of the global atmosphere). Winds redistribute momentum and heat, and short- and long-term predictions of wind characteristics have applications to a number of socioeconomic sectors (e.g., engineering infrastructure). Despite its importance, atmospheric flow (i.e., wind) has been subject to less research within the climate downscaling community than variables such as air temperature and precipitation. However, there is a growing comprehension that wind storms are the single biggest source of “weather-related” insurance losses in Europe and North America in the contemporary climate, and that possible changes in wind regimes and intense wind events as a result of global climate non-stationarity are of importance to a variety of potential climate change feedbacks (e.g., emission of sea spray into the atmosphere), ecological impacts (such as wind throw of trees), and a number of other socioeconomic sectors (e.g., transportation infrastructure and operation, electricity generation and distribution, and structural design codes for buildings). There are a number of specific challenges inherent in downscaling wind including, but not limited to, the fact that it has both magnitude (wind speed) and orientation (wind direction). Further, for most applications, it is necessary to accurately downscale the full probability distribution of values at short timescales (e.g., hourly), including extremes, while the mean wind speed averaged over a month or year is of little utility. Dynamical, statistical, and hybrid approaches have been developed to downscale different aspects of the wind climate, but have large uncertainties in terms of high-impact aspects of the wind (e.g., extreme wind speeds and gusts). The wind energy industry is a key application for right-scaled wind parameters and has been a major driver of new techniques to increase fidelity. Many opportunities remain to refine existing downscaling methods, to develop new approaches to improve the skill with which the spatiotemporal scales of wind variability are represented, and for new approaches to evaluate skill in the context of wind climates.

Article

B.N. Goswami and Soumi Chakravorty

Lifeline for about one-sixth of the world’s population in the subcontinent, the Indian summer monsoon (ISM) is an integral part of the annual cycle of the winds (reversal of winds with seasons), coupled with a strong annual cycle of precipitation (wet summer and dry winter). For over a century, high socioeconomic impacts of ISM rainfall (ISMR) in the region have driven scientists to attempt to predict the year-to-year variations of ISM rainfall. A remarkably stable phenomenon, making its appearance every year without fail, the ISM climate exhibits a rather small year-to-year variation (the standard deviation of the seasonal mean being 10% of the long-term mean), but it has proven to be an extremely challenging system to predict. Even the most skillful, sophisticated models are barely useful with skill significantly below the potential limit on predictability. Understanding what drives the mean ISM climate and its variability on different timescales is, therefore, critical to advancing skills in predicting the monsoon. A conceptual ISM model helps explain what maintains not only the mean ISM but also its variability on interannual and longer timescales. The annual ISM precipitation cycle can be described as a manifestation of the seasonal migration of the intertropical convergence zone (ITCZ) or the zonally oriented cloud (rain) band characterized by a sudden “onset.” The other important feature of ISM is the deep overturning meridional (regional Hadley circulation) that is associated with it, driven primarily by the latent heat release associated with the ISM (ITCZ) precipitation. The dynamics of the monsoon climate, therefore, is an extension of the dynamics of the ITCZ. The classical land–sea surface temperature gradient model of ISM may explain the seasonal reversal of the surface winds, but it fails to explain the onset and the deep vertical structure of the ISM circulation. While the surface temperature over land cools after the onset, reversing the north–south surface temperature gradient and making it inadequate to sustain the monsoon after onset, it is the tropospheric temperature gradient that becomes positive at the time of onset and remains strongly positive thereafter, maintaining the monsoon. The change in sign of the tropospheric temperature (TT) gradient is dynamically responsible for a symmetric instability, leading to the onset and subsequent northward progression of the ITCZ. The unified ISM model in terms of the TT gradient provides a platform to understand the drivers of ISM variability by identifying processes that affect TT in the north and the south and influence the gradient. The predictability of the seasonal mean ISM is limited by interactions of the annual cycle and higher frequency monsoon variability within the season. The monsoon intraseasonal oscillation (MISO) has a seminal role in influencing the seasonal mean and its interannual variability. While ISM climate on long timescales (e.g., multimillennium) largely follows the solar forcing, on shorter timescales the ISM variability is governed by the internal dynamics arising from ocean–atmosphere–land interactions, regional as well as remote, together with teleconnections with other climate modes. Also important is the role of anthropogenic forcing, such as the greenhouse gases and aerosols versus the natural multidecadal variability in the context of the recent six-decade long decreasing trend of ISM rainfall.

Article

A. Johannes Dolman, Luis U. Vilasa-Abad, and Thomas A. J. Janssen

Drylands cover around 40% of the land surface on Earth and are inhabited by more than 2 billion people, who are directly dependent on these lands. Drylands are characterized by a highly variable rainfall regime and inherent vegetation-climate feedbacks that can enhance the resilience of the system, but also can amplify disturbances. In that way, the system may get locked into two alternate stable states: one relatively wet and vegetated, and the other dry and barren. The resilience of dryland ecosystems derives from a number of adaptive mechanisms by which the vegetation copes with prolonged water stress, such as hydraulic redistribution. The stochastic nature of both the vegetation dynamics and the rainfall regime is a key characteristic of these systems and affects its management in relation to the feedbacks. How the ecohydrology of the African drylands will change in the future depends on further changes in climate, human disturbances, land use, and the socioeconomic system.

Article

How do economic conditions affect public opinion about climate change? Since the early days of the modern environmental movement, people have debated three main perspectives on how economic conditions impact environmental attitudes. The post-materialism perspective suggests that social and individual affluence leads to increasing concern and demands for action on climate change through long-run cultural change. A second view suggests that attitudes about climate change are shaped largely independently of economic conditions and reflect the emergence of a new environmental paradigm. A third view, associated with ecological modernization theory, suggests that attitudes about climate change are shaped in important ways by short-term economic factors, such as economic self-interest, and are likely to vary among citizens over time. While all of these perspectives have merit, we emphasize the impact of macroeconomic risk and business cycle fluctuations in shaping public attitudes toward climate change and more general aspects of environmental policy. Rising unemployment rates, for example, tend to be associated with declines in concern about environmental problems. This is a trend that is repeated across more than four decades and multiple recessions and recoveries dating back to the 1970s. Although it is obviously a more recently recognized environmental problem, public attitudes about climate change are also affected considerably by short-run economic conditions. This fact can influence the possibilities for policy reform. Through a process of motivated reasoning, in which immediate concerns and preferences to address economic risk lead individuals to adjust other attitudes about the environment, public concerns about climate change have ebbed and flowed with the business cycle. Other economic factors—such as societal affluence, personal employment status, or income—have more limited effects on attitudes about climate change, at least in most developed countries. The impact of economic risk on public attitudes about climate change has important implications for policy reform in democratic societies, because public support matters. While partisanship and ideology are frequently cited as explanations for fluctuating public opinion about climate change, macroeconomic risk offers a complementary explanation, which suggests that the framing and timing of environmental policy initiatives is as important as ideological acceptability. Positioning environmental actions or initiatives in better economic conditions, emphasizing immediate economic benefits, and countering unwarranted beliefs about personal costs, especially during challenging economic circumstances, should improve the prospects for efforts to address climate change.

Article

Over the past two decades, the global news industry has embarked upon a major project of economic, organizational, and technological restructuring. In organizational terms, successive waves of mergers and buyouts have yielded a global news landscape where most of the larger firms are owned by shareholders and run by executives whose singular focus is on rationalizing news production and improving profitability. Although in some cases, these shareholders and executives have used their authority to influence climate coverage directly, more often their goals are non-ideological: reducing labor costs and increasing revenues. At the same time, in a parallel development, the digital media revolution not only has spawned a host of new online competitors but also has cut deeply into the advertising revenue once enjoyed by traditional media firms. Within legacy news organizations, these industrial and technological trends have converged to dramatically intensify the work pressures facing environmental journalists. For example, in an effort to reduce costs, many firms have reduced newsroom staff to a small core of multi-tasking reporters, supported by a wider web of part-time freelancers. In this process, the science and environment beat is often the first to go, with environmental specialists among the first to be reassigned or downsized (and pushed into freelance work). For all reporters, there is increased pressure to produce more stories in less time on multiple media platforms, a trend that, in turn, enhances the power of special interests to influence climate coverage through public relations and other external information subsidies. Due to these converging industrial and technological trends, environmental reporters now work in a new media ecosystem that is complex, subject to contradictory pressures, and in many ways hostile to the production of high-quality climate news. When the environmental beat is cut, climate change often becomes the purview of general assignment reporters who lack experience and expertise. For their part, freelance specialists continue to cover climate news, but their ability to sustain this coverage over the long term is constrained by their part-time status. Finally, although niche climate blogs have provided welcome spaces for environmental journalists to produce in-depth coverage, these outlets usually reach only tiny audiences composed of the already-engaged. In short, without significant action, the regrettable status quo of climate news—that is, an episodic sprinkling of climate coverage scattered across the media ecosystem—will continue indefinitely. Policy-makers should therefore restore long-term institutional and economic support for environmental journalists specializing in climate science and policy.

Article

Climate change and fisheries have significantly changed the Baltic Sea ecosystem, with the demise of Eastern Baltic cod (Gadus morhua callarias) being the signature development. Cod in the Central Baltic Sea collapsed in the late 1980s as a result of low reproductive success and overfishing. Low recruitment and hence small year-classes were not able to compensate for fishing pressures far above sustainable levels. Recruitment failure can be mainly related to the absence of North Sea water inflows to the Central Baltic deep basins. These major Baltic inflows (MBIs) occurred regularly until the 1980s, when their frequency decreased to a decadal pattern, a development attributed to changes in atmospheric circulation patterns. MBIs are needed for ventilation of otherwise stagnating Baltic deep waters, and their absence caused reduced oxygen and salinity levels in cod-spawning habitats, limiting egg and larval survival. Climate change, on the other hand, has promoted a warmer environment richer in zooplanktonic food for larval Baltic sprat (Sprattus sprattus). Resulting large year-classes and low predation by the collapsed cod stock caused an outburst of the sprat stock that cascaded down to the zoo- and phytoplankton trophic levels. Furthermore, a large sprat population controlled cod recruitment and hence hindered a recovery of the stock by predation on cod eggs, limiting cod larval food supply. The change in ecosystem structure and function caused by the collapse of the cod stock was a major part and driver of an ecosystem regime shift in the Central Baltic Sea during the period 1988 to 1993. This reorganization of ecosystem structure involved all trophic levels from piscivorous and planktivorous fish to zoo- and phytoplankton. The observed large-scale ecosystem changes displayed the characteristics of a discontinuous regime shift, initiated by climate-induced changes in the abiotic environment and stabilized by feedback loops in the food web. Discontinuous changes such as regime shifts are characteristically difficult to reverse, and the Baltic ecosystem recently rather shows signs of increasing ecological novelty for which the failed recovery of the cod stock despite a reduction in fishing pressure is a clear symptom. Unusually widespread deficient oxygen conditions in major cod-spawning areas have altered the overall productivity of the population by negatively affecting growth and recruitment. Eutrophication as a consequence of intensive agriculture is the main driver for anoxia in the Baltic Sea amplified by the effects on continuing climate change and stabilized by self-enforcing feedbacks. Developing ecological novelty in the Baltic Sea hence requires true cross-sectoral ecosystem-based management approaches that truly integrate eutrophication combatment, species conservation, and living resources management.

Article

Courtney Plante, Johnie J. Allen, and Craig A. Anderson

Given the dire nature of many researchers’ predictions about the effects of global climate change (e.g., rising sea levels, droughts, more extreme weather), it comes as little surprise that less attention has been paid to the subtler, less direct outcomes of rapid climate change: psychological, sociological, political, and economic effects. In this chapter we explore one such outcome in particular: the effects of rapid climate change on aggression. We begin by exploring the potential for climate change to directly affect aggression in individuals, focusing on research showing the relationship between uncomfortably hot ambient temperature and aggression. Next, we review several lines of research illustrating ways that climate change can indirectly increase aggression in individuals. We then shift our focus from individuals to the effects of climate change on group-level aggression. We finish by addressing points of contention, including the challenge that the effects of climate change on aggression are too remote and too small to be considered relevant.

Article

Early research on the relationship between social media use and its relationship to climate change opinion, knowledge, and behavior suggests several positive impacts. Social media encourages greater knowledge of climate change, mobilization of climate change activists, space for discussing the issue with others, and online discussions that frame climate change as a negative for society. Social media, however, does provide space for framing climate change skeptically and activating those with a skeptical perspective of climate change. Further examination of the relationship between social media use and climate change perceptions is warranted.

Article

For the general public, the news media are an important source of information about climate change. They have significant potential to influence public understanding and perceptions of the issue. Television news, because of its visual immediacy and authoritative presentation, is likely to be particularly influential. Numerous studies have shown that television news can affect public opinion directly and indirectly through processes such as agenda setting and framing. Moreover, even in a fragmented media environment largely dominated by online communication, television remains a prominent medium through which citizens follow news about science issues. Given this, scholars over the last several decades have endeavored to map the content of television news reporting on climate change and its effects on public opinion and knowledge. Results from this research suggest that journalists’ adherence to professional norms such as balance, novelty, dramatization, and personalization, along with economic pressures and sociopolitical influences, have produced inaccuracies and distortions in television news coverage of climate change. For example, content analyses have found that U.S. network television news stories tend to over-emphasize dramatic impacts and imagery, conflicts between political groups and personalities, and the uncertainty surrounding climate science and policy. At the same time, those skeptical of climate change have been able to exploit journalists’ norms of balance and objectivity to amplify their voices in television coverage of climate change. In particular, the increasingly opinionated 24-hour cable news networks have become a megaphone for ideological viewpoints on climate change. In the United States, a coordinated climate denial movement has used Fox News to effectively spread its message discrediting climate science. Coverage on Fox News is overwhelmingly dismissive of climate change and disparaging toward climate science and scientists. Coverage on CNN and MSNBC is more accepting of climate change; however, while MSNBC tends to vilify the conservative opposition to climate science and policy, and occasionally exaggerates the impacts of climate change, CNN sends more mixed signals. Survey and experimental analyses indicate that these trends in television news coverage of climate change have important effects on public opinion and may, in particular, fuel confusion and apathy among the general U.S. public and foster opinion extremity among strong partisans.

Article

Elevation-dependent climate change has been observed in the European Alps in the context of global warming and as a consequence of Alpine orography. It is most obvious in elevation-dependent warming, conveniently defined as the linear regression of the time series of temperatures against elevation, and it reaches values of several tenths of a degree per 1,000 m elevation per decade. Observed changes in temperature have forced changes in atmospheric pressure, water vapor, cloud condensation, fluxes of infrared and solar radiation, snow cover, and evaporation, which have affected the Alpine surface energy and water balance in different ways at different elevations. At the same time, changes in atmospheric aerosol optical depth, in atmospheric circulation, and in the frequency of weather types have contributed to the observed elevation-dependent climate change in the European Alps. To a large extent, these observations have been reproduced by model simulations.

Article

As a unique and high gigantic plateau, the Tibetan Plateau (TP) is sensitive and vulnerable to global climate change, and its climate change tendencies and the corresponding impact on regional ecosystems and water resources can provide an early alarm for global and mid-latitude climate changes. Growing evidence suggests that the TP has experienced more significant warming than its surrounding areas during past decades, especially at elevations higher than 4 km. Greater warming at higher elevations than at lower elevations has been reported in several major mountainous regions on earth, and this interesting phenomenon is known as elevation-dependent climate change, or elevation-dependent warming (EDW). At the beginning of the 21st century, Chinese scholars first noticed that the TP had experienced significant warming since the mid-1950s, especially in winter, and that the latest warming period in the TP occurred earlier than enhanced global warming since the 1970s. The Chinese also first reported that the warming rates increased with the elevation in the TP and its neighborhood, and the TP was one of the most sensitive areas to global climate change. Later, additional studies, using more and longer observations from meteorological stations and satellites, shed light on the detailed characteristics of EDW in terms of mean, minimum, and maximum temperatures and in different seasons. For example, it was found that the daily minimum temperature showed the most evident EDW in comparison to the mean and daily maximum temperatures, and EDW is more significant in winter than in other seasons. The mean daily minimum and maximum temperatures also maintained increasing trends in the context of EDW. Despite a global warming hiatus since the turn of the 21st century, the TP exhibited persistent warming from 2001 to 2012. Although EDW has been demonstrated by more and more observations and modeling studies, the underlying mechanisms for EDW are not entirely clear owing to sparse, discontinuous, and insufficient observations of climate change processes. Based on limited observations and model simulations, several factors and their combinations have been proposed to be responsible for EDW, including the snow-albedo feedback, cloud-radiation effects, water vapor and radiative fluxes, and aerosols forcing. At present, however, various explanations of the mechanisms for EDW are mainly derived from model-based research, lacking more solid observational evidence. Therefore, to comprehensively understand the mechanisms of EDW, a more extensive and multiple-perspective climate monitoring system is urgently needed in the areas of the TP with high elevations and complex terrains. High-elevation climate change may have resulted in a series of environmental consequences, such as vegetation changes, permafrost melting, and glacier shrinkage, in mountainous areas. In particular, the glacial retreat could alter the headwater environments on the TP and the hydrometeorological characteristics of several major rivers in Asia, threatening the water supply for the people living in the adjacent countries. Taking into account the climate-model projections that the warming trend will continue over the TP in the coming decades, this region’s climate change and the relevant environmental consequences should be of great concern to both scientists and the general public.

Article

Maxwell Boykoff and Gesa Luedecke

During the past three decades, elite news media have become influential translators of climate change linking science, policy, and the citizenry. Historical trends in public discourse—shaped in significant part by elite media—demonstrate news media’s critical role in shaping public perception and the level of concern towards climate change. Media representations of climate change and global warming are embedded in social, cultural, political, and economic dimensions that influence individual-level processes such as everyday journalistic practices. Media have a strong influence on policy decision-making, attitudes, perspectives, intentions, and behavioral change, but those connections can be challenging to pinpoint; consequently, examinations of elite news coverage of climate change, particularly in recent decades, have sought to gain a stronger understanding of these complex and dynamic webs of interactions. In so doing, research has more effectively traced how media have taken on varied roles in the climate change debate, from watch dogs to lap dogs to guard dogs in the public sphere. Within these areas of research, psychological aspects of media influence have been relatively underemphasized. However, interdisciplinary and problem-focused research investigations of elite media coverage stand to advance considerations of public awareness, discourse, and engagement. Elite news media critically contribute to public discourse and policy priorities through their “mediating” and interpretative influences. Therefore, a review of examinations of these dynamics illuminate the bridging role of elite news coverage of climate change between formal science and policy, and everyday citizens in the public sphere.

Article

George Adamson

The El Niño Southern Oscillation is considered to be the most significant form of “natural” climate variability, although its definition and the scientific understanding of the phenomenon are continually evolving. Since its first recorded usage in 1891, the meaning of “El Niño” has morphed from a regular local current affecting coastal Peru, to an occasional Pacific-wide phenomenon that modifies weather patterns throughout the world, and finally to a diversity of weather patterns that share similarities in Pacific heating and changes in trade-wind intensity, but exhibit considerable variation in other ways. Since the 1960s El Niño has been associated with the Southern Oscillation, originally defined as a statistical relationship in pressure patterns across the Pacific by the British-Indian scientist Gilbert Walker. The first unified model for the El Niño-Southern Oscillation (ENSO) was developed by Jacob Bjerknes in 1969 and it has been updated several times since, but no simple model yet explains apparent diversity in El Niño events. ENSO forecasting is considered a success, but each event still displays surprising characteristics.

Article

Empirical-statistical downscaling (ESD) models use statistical relationships to infer local climate information from large-scale climate information produced by global climate models (GCMs), as an alternative to the dynamical downscaling provided by regional climate models (RCMs). Among various statistical downscaling approaches, the nonlinear methods are mainly used to construct downscaling models for local variables that strongly deviate from linearity and normality, such as daily precipitation. These approaches are also appropriate to handle downscaling of extreme rainfall. There are nonlinear downscaling techniques of various complexities. The simplest one is represented by the analog method that originated in the late 1960s from the need to obtain local details of short-term weather forecasting for various variables (air temperature, precipitation, wind, etc.). Its first application as a statistical downscaling approach in climate science was carried out in the late 1990s. More sophisticated statistical downscaling models have been developed based on a wide range of nonlinear functions. Among them, the artificial neural network (ANN) was the first nonlinear regression–type method used as a statistical downscaling technique in climate science in the late 1990s. The ANN was inspired by the human brain, and it was used early in artificial intelligence and robotics. The impressive development of machine learning algorithms that can automatically extract information from a vast amount of data, usually through nonlinear multivariate models, contributed to improvements of ANN downscaling models and the development of other new, machine learning-based downscaling models to overcome some ANN drawbacks, such as support vector machine and random forest techniques. The mixed models combining various machine learning downscaling approaches maximize the downscaling skill in local climate change applications, especially for extreme rainfall indices. Other nonlinear statistical downscaling approaches refer to conditional weather generators, combining a standard weather generator (WG) with a separate statistical downscaling model by conditioning the WG parameters on large-scale predictors via a nonlinear approach. The most popular ways to condition the WG parameters are the weather-type approach and generalized linear models. This article discusses various aspects of nonlinear statistical downscaling approaches, their strengths and weaknesses, as well as comparison with linear statistical downscaling models. A proper validation of the nonlinear statistical downscaling models is an important issue, allowing selection of an appropriate model to obtain credible information on local climate change. Selection of large-scale predictors, the model’s ability to reproduce historical trends, extreme events, and the uncertainty related to future downscaled changes are important issues to be addressed. A better estimation of the uncertainty related to downscaled climate change projections can be achieved by using ensembles of more GCMs as drivers, including their ability to simulate the input in downscaling models. Comparison between more future statistical downscaled climate change signals and those derived from dynamical downscaling driven by the same global model, including a complex validation of the RCMs, gives a measure of the reliability of downscaled regional climate changes.

Article

Jin-Song von Storch

The energetics considerations based on Lorenz’s available potential energy A focus on identification and quantification of processes capable of converting external energy sources into the kinetic energy of atmospheric and oceanic general circulations. Generally, these considerations consist of: (a) identifying the relevant energy compartments from which energy can be converted against friction to kinetic energy of motions of interests; (b) formulating for these energy compartments budget equations that describe all possible energy pathways; and (c) identifying the dominant energy pathways using realistic data. In order to obtain a more detailed description of energy pathways, a partitioning of motions, for example, into a “mean” and an “eddy” component, or into a diabatic and an adiabatic component, is used. Since the budget equations do not always suggest the relative importance of all possible pathways, often not even the directions, data that describe the atmospheric and the oceanic state in a sufficiently accurate manner are needed for evaluating the energy pathways. Apart from the complication due to different expressions of A , ranging from the original definition by Lorenz in 1955 to its approximations and to more generally defined forms, one has to balance the complexity of the respective budget equations that allows the evaluation of more possible energy pathways, with the quality of data available that allows sufficiently accurate estimates of energy pathways. With regard to the atmosphere, our knowledge, as inferred from the four-box Lorenz energy cycle, has consolidated in the last two decades, by, among other means, using data assimilation products obtained by combining observations with realistic atmospheric general circulation models (AGCMs). The eddy kinetic energy, amounting to slightly less than 50% of the total kinetic energy, is supported against friction through a baroclinic pathway “fueled” by the latitudinally dependent diabatic heating. The mean kinetic energy is supported against friction by converting eddy kinetic energy via inverse cascades. For the ocean, our knowledge is still emerging. The description through the four-box Lorenz energy cycle is approximative and was only estimated from a simulation of a 0 . 1 ° oceanic general circulation models (OGCM) realistically forced at the sea surface, rather than from a data assimilation product. The estimates obtained so far suggest that the oceanic eddy kinetic energy, amounting almost 75% of the total oceanic kinetic energy, is supported against friction through a baroclinic pathway similar to that in the atmosphere. However, the oceanic baroclinic pathway is “fueled” to a considerable extent by converting mean kinetic energy supported by winds into mean available potential energy. Winds are also the direct source of the kinetic energy of the mean circulation, without involving noticeable inverse cascades from transients, at least not for the ocean as a whole. The energetics of oceanic general circulation can also be examined by separating diabatic from adiabatic processes. Such a consideration is thought to be more appropriate for understanding the energetics of the oceanic meridional overturning circulation (MOC), since this circulation is sensitive to density changes induced by diabatic mixing. Further work is needed to quantify the respective energy pathways using realistic data.

Article

Stabilizing atmospheric greenhouse gases will require very large reductions in energy-related carbon dioxide emissions. This can be achieved only through continuous innovation, aggressive and ongoing. Fast-paced innovation, in turn, depends on rapid and widespread diffusion, adoption, adaptation—in short, on technological learning. These processes are integrally linked, as virtuous circles, through feedback loops embedded in economic markets. The overall dynamics are fundamentally incremental. Pundits and policymakers, nonetheless, sometimes seem to hope that “breakthroughs” will emerge to sweep existing energy technologies aside. Such hopes are misplaced, for two reasons. If breakthroughs are construed as something “new under the sun,” they are rare and unpredictable, and policymakers have few tools to foster them. Energy technologies, after all, have been intensively explored over the past two centuries: the physical constraints are well understood and there are few reasons to expect research to lead to anything fundamentally new. Infant technologies, second, tend to perform poorly, and to be quite costly. Improvements come over time though technological learning. Inputs to this sort of learning range from field service experience to “just-in-time” research. Economic competition provides much of the driving force. The dynamics just sketched are broadly representative of the evolutionary paths traced by past energy technologies—wind and steam power, gas turbines, nuclear power, and solar photovoltaic (PV) cells and systems. Similar paths will be followed if prospective innovations such as carbon capture and storage, small nuclear reactors, or schemes for tapping the energy of the world’s oceans begin to mature and diffuse. Over the next several decades, the world should expect to work with existing technologies in various stages of maturation that can and will—because this is inherent in the process of innovation—advance on technical measures of performance (e.g., energy conversion efficiency) and come down in costs (in most cases) through continuous improvement. This sort of innovation is first and foremost the work of profit-seeking businesses, enterprises that conceive, develop, introduce, and market new technologies. These firms exploit publically funded R&D; just as important historically, government procurements have created initial markets, including the first PV cells and also the gas turbines that many utilities now buy for electric power generation, the early versions of which were based on designs for military aircraft. A major task for energy-climate policy is to create similarly viable market segments in which new and emerging technologies can gain a foothold, as a number of governments have done for battery-electric vehicles. Direct and indirect subsidies—financial preferences as provided in some countries for battery-electric vehicles, and market set-asides, as for biofuels in Europe, Brazil, and the United States—insulate firms from potential competition, creating opportunities to push forward technologically, overcoming early handicaps, such as high costs and poor performance, associated with emerging technologies. The implication: Effective innovation policies must provide powerful incentives for profit-seeking businesses. This is true worldwide, although mechanisms will differ from country to country.

Article

Images are a key part of the climate change communication process. The diverse and interdisciplinary literature on how people engage with visual representations of climate change is reviewed. Images hold particular power for engaging people, as they hold three qualities that differ from other communication devices (such as words or text): they are analogical, they lack an explicit propositional syntax, and they are indexical. These qualities are explored in relation to climate change imagery. A number of visual tropes common to climate change communication (identifiable people; climate change impacts; energy, emissions and pollution; protest; scientific imagery) are examined and the evidence for each of these visual tropes in terms of how they engage particular audiences is reviewed. Two case studies, of polar bear imagery and the “hockey stick” graph image, critically examine iconic imagery associated with climate change, and how and why these types of images may (dis)engage audiences. Six best-practice guidelines for visual climate change communication are presented and three areas for further research in this nascent field are suggested.

Article

Although there is an abundance of social scientific research focused on public opinion and climate change, there remains much to learn about how individuals come to understand, feel, and behave relative to this issue. Efforts to understand these processes are commonly directed toward media depictions, because media represent a primary conduit through which people encounter information about climate change. The majority of research in this area has focused on news media portrayals of climate change. News media depictions, however, represent only a part of the media landscape, and a relatively small but growing body of work has focused on examining portrayals of climate change in entertainment media (i.e., films, television programs, etc.) and their implications. This article provides a comprehensive overview of this area of research, summarizing what is currently known about portrayals of climate change in entertainment media, the individual-level effects of these portrayals, and areas ripe for future research. Our overview suggests that the extant work has centered primarily on a small subset of high-profile climate change films. Examination of the content of these films has been mostly rhetorical and has often presumed negative audience effects. Studies that specifically set out to explore possible effects have often unearthed evidence suggesting short-term contributions to viewers’ perceptions of climate change, specifically in terms of heightened awareness, concern, and motivation. Improving the breadth and depth of research in this area, we contend, can stem from more robust theorizing, analyses that focus on a more diverse menu of entertainment media and the interactions among them, and increasingly complex analytical efforts to capture long-term effects.