You are looking at 1-10 of 212 articles
Pastoralists around the world are exposed to climate change and increasing climate variability. Various downscaled regional climate models in Africa support community reports of rising temperatures as well as changes in the seasonality of rainfall and drought. In addition to climate, pastoralists have faced a second exposure to unsupportive policy environments. Dating back to the colonial period, a lack of knowledge about pastoralism and a systemic marginalization of pastoral communities influenced the size and nature of government investments in pastoral lands. National governments prioritized farming communities and failed to pay adequate attention to drylands and pastoral communities. The limited government interventions that occurred were often inconsistent with contemporary realities of pastoralism and pastoral communities. These included attempts at sedentarization and modernization, and in other ways changing the priorities and practices of pastoral communities.
The survival of pastoral communities in Africa in the context of this double exposure has been a focus for scholars, development practitioners, as well as national governments in recent years. Scholars initially drew attention to pastoralists’ drought-coping strategies, and later examined the multiple ways in which pastoralists manage risk and exploit unpredictability. It has been learned that pastoralists are rational land managers whose experience with variable climate has equipped them with the skills needed for adaptation. Pastoralists follow several identifiable adaptation paths, including diversification and modification of their herds and herding strategies; adoption of livelihood activities that did not previously play a permanent role; and a conscious decision to train the next generation for nonpastoral livelihoods. Ongoing government interventions around climate change still prioritize cropping over herding. Sometimes, such nationally supported adaptation plans can undermine community-based adaptation practices, autonomously evolving within pastoral communities. Successful adaptation hinges on recognition of the value of autonomous adaptation and careful integration of such adaptation with national plans.
Ronald D. Brunner and Amanda H. Lynch
Adaptive governance is defined by a focus on decentralized decision-making structures and procedurally rational policy, supported by intensive natural and social science. Decentralized decision-making structures allow a large, complex problem like global climate change to be factored into many smaller problems, each more tractable for policy and scientific purposes. Many smaller problems can be addressed separately and concurrently by smaller communities. Procedurally rational policy in each community is an adaptation to profound uncertainties, inherent in complex systems and cognitive constraints, that limit predictability. Hence planning to meet projected targets and timetables is secondary to continuing appraisal of incremental steps toward long-term goals: What has and hasn’t worked compared to a historical baseline, and why? Each step in such trial-and-error processes depends on politics to balance, if not integrate, the interests of multiple participants to advance their common interest—the point of governance in a free society. Intensive science recognizes that each community is unique because the interests, interactions, and environmental responses of its participants are multiple and coevolve. Hence, inquiry focuses on case studies of particular contexts considered comprehensively and in some detail.
Varieties of adaptive governance emerged in response to the limitations of scientific management, the dominant pattern of governance in the 20th century. In scientific management, central authorities sought technically rational policies supported by predictive science to rise above politics and thereby realize policy goals more efficiently from the top down. This approach was manifest in the framing of climate change as an “irreducibly global” problem in the years around 1990. The Intergovernmental Panel on Climate Change (IPCC) was established to assess science for the Conference of the Parties (COP) to the U.N. Framework Convention on Climate Change (UNFCCC). The parties negotiated the Kyoto Protocol that attempted to prescribe legally binding targets and timetables for national reductions in greenhouse gas emissions. But progress under the protocol fell far short of realizing the ultimate objective in Article 1 of the UNFCCC, “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference in the climate system.” As concentrations continued to increase, the COP recognized the limitations of this approach in Copenhagen in 2009 and authorized nationally determined contributions to greenhouse gas reductions in the Paris Agreement in 2015.
Adaptive governance is a promising but underutilized approach to advancing common interests in response to climate impacts. The interests affected by climate, and their relative priorities, differ from one community to the next, but typically they include protecting life and limb, property and prosperity, other human artifacts, and ecosystem services, while minimizing costs. Adaptive governance is promising because some communities have made significant progress in reducing their losses and vulnerability to climate impacts in the course of advancing their common interests. In doing so, they provide field-tested models for similar communities to consider. Policies that have worked anywhere in a network tend to be diffused for possible adaptation elsewhere in that network. Policies that have worked consistently intensify and justify collective action from the bottom up to reallocate supporting resources from the top down. Researchers can help realize the potential of adaptive governance on larger scales by recognizing it as a complementary approach in climate policy—not a substitute for scientific management, the historical baseline.
Bjørn H. Samset
Among the factors that affect the climate, few are as diverse and challenging to understand as aerosols. Minute particles suspended in the atmosphere, aerosols are emitted through a wide range of natural and industrial processes, and are transported around the globe by winds and weather. Once airborne, they affect the climate both directly, through scattering and absorption of solar radiation, and indirectly, through their impact on cloud properties. Combining all their effects, anthropogenic changes to aerosol concentrations are estimated to have had a climate impact over the industrial era that is second only to CO2. Their atmospheric lifetime of only a few days, however, makes their climate effects substantially different from those of well-mixed greenhouse gases.
Major aerosol types include sea salt, dust, sulfate compounds, and black carbon—or soot—from incomplete combustion. Of these, most scatter incoming sunlight back to space, and thus mainly cool the climate. Black carbon, however, absorbs sunlight, and therefore acts as a heating agent much like a greenhouse gas. Furthermore, aerosols can act as cloud condensation nuclei, causing clouds to become whiter—and thus more reflecting—further cooling the surface. Black carbon is again a special case, acting to change the stability of the atmosphere through local heating of the upper air, and also changing the albedo of the surface when it is deposited on snow and ice, for example.
The wide range of climate interactions that aerosols have, and the fact that their distribution depends on the weather at the time and location of emission, lead to large uncertainties in the scientific assessment of their impact. This in turn leads to uncertainties in our present understanding of the climate sensitivity, because while aerosols have predominantly acted to oppose 20th-century global warming by greenhouse gases, the magnitude of aerosol effects on climate is highly uncertain.
Finally, aerosols are important for large-scale climate events such as major volcanoes, or the threat of nuclear winter. The relative ease with which they can be produced and distributed has led to suggestions for using targeted aerosol emissions to counteract global warming—so-called climate engineering.
Anthony Leiserowitz and Nicholas Smith
Affective imagery, or connotative meanings, play an important role in shaping public risk perceptions, policy support, and broader responses to climate change. These simple “top-of-mind” associations and their related affect help reveal how diverse audiences understand and interpret global warming. And as a relatively simple set of measures, they are easily incorporated into representative surveys, making it possible to identify, measure, and monitor how connotative meanings are distributed throughout a population and how they change over time. Affective image analysis can help identify distinct interpretive communities of like-minded individuals who share their own set of common meanings and interpretations. The images also provide a highly sensitive measure of changes in public discourse. As scientists, political elites, advocates, and the media change the frames, images, icons, and emotions they use to communicate climate change, they can influence the interpretations of the larger public. Likewise, as members of the public directly or vicariously experience specific events or learn more about climate risks, they construct their own connotative meanings, which can in turn influence larger currents of public discourse. This article traces the development of affective imagery analysis, reviews the studies that have implemented it, examines how affective images influence climate change risk perceptions and policy support, and charts several future directions of research.
Social scientists and media critics have often been befuddled about how and why news coverage of important issues takes the shapes that it does. While some issues seem to behave according to well-established patterns, others don’t. The issue of climate change is one that has been explained in numerous ways, often from a cyclical perspective. This perspective suggests that news attention naturally varies up and down, often cued by certain focusing events that draw attention for a time, after which attention wanes again. These observations are usually matched with the perspective that attention should normatively not be cyclical, that the issue is one that deserves continuous attention until it is resolved.
All of this is in the context that there are significant doubts about the objective role of newsmakers in this process. Climate change is an issue that has cut across a period of news evolution in which objectively neutral news has become even less prominent than it once was, if it ever was. News outlets with specific ideological agendas, a plethora of bloggers and websites with an axe to grind, and a variety of conspiracy theories about climate have obscured how news can even hope to cover this issue. With “belief” in climate change now becoming an important token of how one identifies oneself politically, we can wonder whether the issue can ever receive a fair hearing from a scientific perspective.
Linda S. Prokopy, Wendy-Lin Bartels, Gary Burniske, and Rebecca Power
Agricultural extension has evolved over the last 200 years from a system of top-down dissemination of information from experts to farmers to a more complex system, in which a diversity of knowledge producers and farmers work together to co-produce information. Following a detailed history of the evolution of extension in the United States, this article describes an example from the southeastern United States that illustrates how innovative institutional arrangements enable land-grant universities to actively engage farmers and extension agents as key partners in the knowledge generation process. A second U.S. example shows that private retailers are more influential than extension in influencing large-scale farmers’ farm management decisions in the midwestern United States. However, these private retailers trust extension as a source of climate change information and thus partnerships are important for extension. Nongovernmental organizations (NGOs) have been an important source of extension services for smallholder farmers across the world, and examples from the NGO CARE indicate that a participatory and facilitative approach works well for climate change communication. Collectively, these examples emphasize that the role of agricultural extension in climate change communication is essential in the context of both developed and developing countries and with both smallholder farmers and large-scale farmers. These case studies illustrate the effectiveness of a co-production approach, the importance of partners and donors, and the changing landscape of agricultural extension delivery.
Julia B. Corbett and Brett Clark
The communication strategy of simply sharing more scientific information has not effectively engaged and connected people to climate change in ways that facilitate understanding and encourage action. In part, this is because climate change is a so-called wicked problem, given that it is socially complex, has many interdependencies, and lacks simple solutions. For many people, climate change is generally seen as something abstract and distant—something that they know about, but do not “feel.” The arts and humanities can play an important role in disrupting the social and cultural worldviews that filter climate information and separate the public from the reality of climate change. Whether it is the visual arts, dance, theater, literature, comedy, or film, the arts and humanities present engaging stories, corporally sensed and felt experiences, awareness of interdependency with the world, emotional meanings, and connection with place. Climate stories, especially those based on lived experiences, offer distinct ways to engage a variety of senses. They allow the “invisibility” of climate change to be seen, felt, and imagined in the past, present, and future. They connect global issues to conditions close to home and create space to grieve and experience loss. They encourage critical reflection of existing social structures and cultural and moral norms, thus facilitating engagement beyond the individual level. The arts and humanities hold great potential to help spur necessary social and cultural change, but research is needed on their reach and efficacy.
Stefano Tibaldi and Franco Molteni
The atmospheric circulation in the mid-latitudes of both hemispheres is usually dominated by westerly winds and by planetary-scale and shorter-scale synoptic waves, moving mostly from west to east. A remarkable and frequent exception to this “usual” behavior is atmospheric blocking. Blocking occurs when the usual zonal flow is hindered by the establishment of a large-amplitude, quasi-stationary, high-pressure meridional circulation structure which “blocks” the flow of the westerlies and the progression of the atmospheric waves and disturbances embedded in them. Such blocking structures can have lifetimes varying from a few days to several weeks in the most extreme cases. Their presence can strongly affect the weather of large portions of the mid-latitudes, leading to the establishment of anomalous meteorological conditions. These can take the form of strong precipitation episodes or persistent anticyclonic regimes, leading in turn to floods, extreme cold spells, heat waves, or short-lived droughts. Even air quality can be strongly influenced by the establishment of atmospheric blocking, with episodes of high concentrations of low-level ozone in summer and of particulate matter and other air pollutants in winter, particularly in highly populated urban areas.
Atmospheric blocking has the tendency to occur more often in winter and in certain longitudinal quadrants, notably the Euro-Atlantic and the Pacific sectors of the Northern Hemisphere. In the Southern Hemisphere, blocking episodes are generally less frequent, and the longitudinal localization is less pronounced than in the Northern Hemisphere.
Blocking has aroused the interest of atmospheric scientists since the middle of the last century, with the pioneering observational works of Berggren, Bolin, Rossby, and Rex, and has become the subject of innumerable observational and theoretical studies. The purpose of such studies was originally to find a commonly accepted structural and phenomenological definition of atmospheric blocking. The investigations went on to study blocking climatology in terms of the geographical distribution of its frequency of occurrence and the associated seasonal and inter-annual variability. Well into the second half of the 20th century, a large number of theoretical dynamic works on blocking formation and maintenance started appearing in the literature. Such theoretical studies explored a wide range of possible dynamic mechanisms, including large-amplitude planetary-scale wave dynamics, including Rossby wave breaking, multiple equilibria circulation regimes, large-scale forcing of anticyclones by synoptic-scale eddies, finite-amplitude non-linear instability theory, and influence of sea surface temperature anomalies, to name but a few. However, to date no unique theoretical model of atmospheric blocking has been formulated that can account for all of its observational characteristics.
When numerical, global short- and medium-range weather predictions started being produced operationally, and with the establishment, in the late 1970s and early 1980s, of the European Centre for Medium-Range Weather Forecasts, it quickly became of relevance to assess the capability of numerical models to predict blocking with the correct space-time characteristics (e.g., location, time of onset, life span, and decay). Early studies showed that models had difficulties in correctly representing blocking as well as in connection with their large systematic (mean) errors.
Despite enormous improvements in the ability of numerical models to represent atmospheric dynamics, blocking remains a challenge for global weather prediction and climate simulation models. Such modeling deficiencies have negative consequences not only for our ability to represent the observed climate but also for the possibility of producing high-quality seasonal-to-decadal predictions. For such predictions, representing the correct space-time statistics of blocking occurrence is, especially for certain geographical areas, extremely important.
Guoxiong Wu, Anmin Duan, and Yimin Liu
With an average elevation of 4 kilometers, a combined area of more than 2.5 million square kilometers, and a variety of complicated landscapes, the Tibetan Plateau (TP) constitutes the highest and largest terrain on earth. The Tibetan and Iranian Plateau (TIP) form a dynamically coupled system that exerts a tremendous impact on the regional and global climate.
The TIP’s geographic location in the subtropics of central and eastern Asia, along with its altitude, size, and steep terrain on the southern and eastern slopes, make this climate impact particularly unique. In winter, the TIP reacts to the impinging subtropical westerly flow, producing a strong negative mountain torque and forming a prominent stationary circulation dipole with a huge anticyclone circulation to its north and cyclone circulation to its south in the tropics. A specific winter climate pattern over Asia is thus formed.
Due to its high elevation, the total mass of the air column over the TP is much smaller than over the neighboring regions, as the solar radiation heating in this region is more efficient. The atmospheric heating source (AHS) over the TP is negative in winter and strongly positive in summer. On this elevated terrain there is also a large number of intersecting isentropic surfaces in the lower troposphere. Along its sloping surfaces, the cooling in winter causes the near-surface air to slide downward and diverge toward its surroundings, whereas the surface heating of the slope in summer results in near-surface air ascent, causing the surrounding air to converge toward the plateau. More significantly, due to its huge size, the surface-sensible heating of the TIP produces a large-scale surface cyclonic circulation and works as an immense sensible-heat-driven air pump (SHAP), which transports abundant water vapor from ocean to land to support the Asian continental monsoon. In addition, the plateau’s heating produces a subtropical monsoonal meridional circulation and creates a large-scale air ascent background in subtropical Asia. Therefore, the Asian monsoon is the consequence of the seasonal change not only in land-sea thermal contrast but also in the thermal forcing of large-scale mountains.
Since the 1980s, the near surface atmospheric warming amplitude over the TP has grown much larger than the global mean, and the changes in climate and AHS over the TP have already influenced the water resources, ecosystem services, mountain hazards, and livelihoods across and around the TP. Understanding the climate effect of the TP’s AHS is not only a key issue for climate dynamics, but can also help us to recognize the thermal forcing of other large-scale topographies, such as the Rockies and Andes Mountains, on the global climate in the framework of land-air-sea interaction.
This article will introduce the effect of the TP’s AHS on the regional climate, with emphasis on the East Asian summer monsoon (EASM) and South Asian summer monsoon (SASM), in terms of the climatology, intra-seasonal oscillation, interannual variability, and decadal change. Controversies, challenges, and future perspectives on this topic will also be presented. Its informative content can be used as a professional reference for research scientists and professionals in the fields of meteorology, climate dynamics, environmental science, geography and geology, hydrology, and paleo-climatology. Most material presented here can also be helpful for non-specialists.
Donald W. Hine, Wendy J. Phillips, Aaron B. Driver, and Mark Morrison
Scientists and policy makers face significant challenges when attempting to engage the public about climate change. An important first step is to understand the number and nature of the audiences one plans to target—a process known as audience segmentation. Segmentation involves identifying, within an audience or target population, homogenous subgroups that share similar demographic and/or psychographic profiles. After segmenting an audience, climate change communicators can target their messages based on the unique characteristics of each subgroup. For example, to stimulate engagement and behavior change, messages aimed at audiences that are skeptical about climate change may require different content and framing than messages aimed at audiences already deeply concerned about climate change.
The notion of matching message content to audience characteristics has a long history, dating back to the Ancient Greeks. More recently, audience segmentation has played a central role in targeted advertising and also social marketing, which uses marketing principles to help “sell” ideas and behaviors that benefit society. Applications to climate change communication are becoming more common, with major segmentation and communication initiatives being implemented across the globe.
Messages crafted to meet the needs of specific audience segments are more likely to be read, understood, and recalled than generic ones, and are also more likely to change behavior. However, despite these successes, the approach has not been uniformly embraced. Controversies have emerged related to the cost effectiveness of segmentation strategies, choice of segmentation variables, potential effects related to social stigmatization, whether segmentation encourages shallow (as opposed to deep) change, the extent to which segments are “found” as opposed to socially constructed by researchers, and whether interindividual differences are best conceptualized in terms of categories or dimensions.