241-260 of 274 Results

Article

Marion Greilinger and Anne Kasper-Giebl

Mineral dust is one of the main natural sources of atmospheric particulate matter, with the Sahara being one of the most important source regions for the occurrence and deposition of mineral dust in Europe. The occurrence of dust events in the European Alps is documented via measurements of airborne dust and its deposits onto the glaciers. Dust events occur mainly in spring, summer, and early autumn. Dust layers are investigated in ice cores spanning the last millennium as well as in annual snow packs. They strongly affect the overall flux of dust-related compounds (e.g., calcium and magnesium), provide an alkaline input to wet deposition chemistry, and change the microbial abundance and diversity of the snow pack. Still airborne mineral dust particles can act as ice nuclei and cloud condensation nuclei, influencing the formation of cloud droplets and hence cloud formation and precipitation. Dust deposits on the snow lead to a darkening of the surface, referred to as “surface albedo reduction,” which influences the timing of the snowmelt and reduces the annual mass balance of glaciers, showing a direct link to glacier retreat as observed presently in a warming climate.

Article

Scientists who study issues such as climate change are often called on by both their colleagues and broader society to share what they know and why it matters. Many are willing to do so—and do it well—but others are either unwilling or may communicate without clear goals or in ways that may fail to achieve their goals. There are several central topics involved in the study of scientists as communicators. First, it is important to understand the evolving arguments behind why scientists are being called on to get involved in public engagement about contentious issues such as climate change. Second, it is also useful to consider the factors that social science suggests actually lead scientists to communicate about scientific issues. Last, it is important to consider what scientists are trying to achieve through their communication activities, and to consider to what extent we have evidence about whether scientists are achieving their desired goals.

Article

Climate journalism is a moving target. Driven by its changing technological and economic contexts, challenged by the complex subject matter of climate change, and immersed in a polarized and politicized debate, climate journalism has shifted and diversified in recent decades. These transformations hint at the emergence of a more interpretive, sometimes advocacy-oriented journalism that explores new roles beyond that of the detached conduit of elite voices. At the same time, different patterns of doing climate journalism have evolved, because climate journalists are not a homogeneous group. Among the diversity of journalists covering the issue, a small group of expert science and environmental reporters stand out as opinion leaders and sources for other journalists covering climate change only occasionally. The former group’s expertise and specialization allow them to develop a more investigative and critical attitude toward both the deniers of anthropogenic climate change and toward climate science.

Article

Daniel P. Aldrich, Courtney M. Page-Tan, and Christopher J. Paul

Anthropogenic climate change increasingly disrupts livelihoods, floods coastal urban cities and island nations, and exacerbates extreme weather events. There is near-universal consensus among scientists that in order to reverse or at least mitigate climate disruptions, limits must be imposed on anthropogenic sources of climate-forcing emissions and adaptation to changing global conditions will be necessary. Yet adaptation to current and future climate change at the individual, community, and national levels vary widely from merely coping, to engaging in adaptive change, to transformative shifts. Some of those affected simply cope with lower crop yields, flooded streets, and higher cooling bills. Others incrementally adapt to new environmental conditions, for example, by raising seawalls or shifting from one crop to another better suited for a hotter environment. The highest—and perhaps least likely—type of change involves transformation, radically altering practices with an eye toward the future. Transformative adaptation may involve a livelihood change or permanent migration; it might require shuttering whole industries and rethinking industrial policy at the national level. Entire island nations such as Fiji, for example, are considering relocating from vulnerable locations to areas better suited to rising sea levels. A great deal of research has shown how social capital (the bonding, bridging, and linking connections to others) provides information on trustworthiness, facilitates collective action, and connects us to external resources during disasters and crises. We know far less about the relationship between social capital and adaptation behaviors in terms of the choices that people make to accommodate changing environmental conditions. A number of unanswered but critical questions remain: How precisely does social capital function in climate change adaptation? To what degree does strong bonding social capital substitute for successful adaptation behaviors for individuals or groups? Which combinations of social factors make coping, adapting, and transforming most likely? How can social capital help migrating populations maintain cultural identity under stress? How can local networks be integrated into higher-level policy interventions to improve adaptation? Which political and social networks contribute to transformative responses to climate change at local, regional, and international levels? This article serves as a comprehensive literature review, overview of empirical findings to date, and a research agenda for the future.

Article

Climate change is often said to herald the anthropocene, where humans become active participants in the remaking of global geology. The corollary of the wide acceptance of a geological anthropocene is the emergence of a new form of self-aware climate agency. With awareness comes blame, invoking responsibility for action. What kind of social action arises from climate agency has become the critical question of our era. In the context of climate deterioration, the prevalence of inaction is itself an exercise of agency, creating in its path new fields of social struggle. The opening sphere of climate agency has the effect of subsuming other fields, reconfiguring established categories of human justice and ethical well-being. In this respect we can think of climate agency as having a distinctive, even revolutionary logic, which remains emergent, enveloping multiple aspects of social action. From this perspective the question of climate change and social movement participation is centrally important. To what extent is something that we can characterize as “climate agency” emerging through social movement participation? What potential has this phenomenon to develop beyond ideological confinement and delimitation to make wider and transformative claims on society? A genuine social movement, we are taught from history, is indeed a transformative force capable of remaking social and political relations. It remains unclear, but what are the emergent dynamics of climate movement participation that depart from established systemic parameters, to offer such a challenge? How are such developments reconfiguring “climate change communication,” forcing an insurgent element into the polity? Though scholarship addressing these questions on social movement participation and climate change exists, the field undoubtedly remains relatively underdeveloped. This reflects the extent to which inquiry into climate change has been dominated by scientific and economic discourses. It also reflects the difficulty that social science, and specifically political sociology, the “home” of social movement studies, has had in apprehending the scope of the challenge. Climate change can disrupt deeply sedimented assumptions about the relationship between social movements and capitalist modernity, and force a reconsideration of the role of social movements across developmentalist hierarchies. Such rethinking can be theoretically challenging, and force new approaches into view. These possibilities reflect the broader challenges to political culture posed by climate change.

Article

Climate change brings profound challenges for social movements. The persistent failure to address climate challenges has driven a rapid “climatization” of politics. Spurred by the climate justice movement, social movements across a broad spectrum have become directly engaged with climate issues. Social movements are defined as groupings of people who act intentionally through an organization or via a network or even as a loose affiliation. They must have a collective identification and capacity for sustained action and participation. Their purpose often is to transform the conditions for social change as key agents in creating a “movement society” of mass political involvement. In doing so, social movements engage in a “metapolitics” of creating power and recreating society. Climate movements are increasingly being shown to have this effect. Recent research demonstrates that with climate change, there is a growing realignment in the social movement field to simultaneously address both climate concerns and social agendas. New forms of social agency are emerging under climate change, posing a new kind of climatized “movement society.” Arguably, as demonstrated by the limited efforts at developing international climate policy, mass mobilization on climate issues is a necessary element of any strategy to secure climate stability. Three broad fields of action are evident – politicising the impacts of climate change, contesting the causes, and advancing solutions. In each there is a widening field of agendas as climate concerns overwhelm existing social relations. Distinctive strategies emerge. First, there is growing collective identification among people affected by the impacts of climate change, now or anticipated, with a marked shift from climate advocacy to climate organizing, of acting “with,” not “for” those affected. Second, actions to challenge the legitimacy of the fossil fuel sector have escalated, materializing the causes of climate change in the fossil fuel cycle. With this, there is a move from abstract demands for emissions reduction to much more concrete demands for fossil fuel phase-out. Finally, in terms of solutions, there is a move from a focus on emission-reduction programs to wider policy agendas designed to transform social relations. Emissions reduction is no longer seen as a burden to be shared, but as part of wider social transformation, of benefit to all.

Article

Masahiro Sugiyama, Atsushi Ishii, Shinichiro Asayama, and Takanobu Kosugi

Climate engineering, a set of techniques proposed to intervene directly in the climate system to reduce risks from climate change, presents many novel governance challenges. Solar radiation management (SRM), particularly the use of stratospheric aerosol injection (SAI), is one of the most discussed proposals. It has been attracting more and more interest, and its pertinence as a potential option for responding to the threats from climate change may be set to increase because of the long-term temperature goal (well below 2°C or 1.5°C) in the 2015 Paris Agreement. Initial research has demonstrated that SAI would cool the climate system and reduce climate risks in many ways, although it is mired in unknown environmental risks and various sociopolitical ramifications. The proposed techniques are in the early stage of research and development (R&D), providing a unique opportunity for upstream public engagement, long touted as a desirable pathway to more plural and inclusive governance of emergent technologies by opening up social choices in technology. Solar geoengineering governance faces various challenges. One of the most acute of these is how to situate public engagement in international governance discourse; the two topics have been studied separately. Another challenge relates to bridging the gap between the social choices at hand and assessment of the risks and benefits of SRM. Deeper integration of knowledge across disciplines and stakeholder and public inputs is a prerequisite for enabling responsible innovation for the future of our climate.

Article

Across many parts of the globe the relationship between journalists and news sources has been transformed by digital technologies, increased reliance on public relations practitioners, and the rise of citizen journalism. With fewer gatekeepers, and the growing influence of digital and social media, identifying whose voices are authoritative in making sense of complex climate science proves an increasing challenge. An increasing array of news sources are vying for their particular perspective to be established including scientists, government, industry, environmental NGOs, individual citizens and, more recently, celebrities. The boundaries between audience, consumer and producer are less defined and the distinction between ‘factual’ and ‘opinion-based’ reporting has become more blurred. All these developments suggest the need for a more complex account of the myriad influences on journalistic decisions. More research needs to examine behind-the-scenes relations between sources and journalists, and the efforts of news sources to frame the issues or seek to silence news media attention. Also although we now know a great deal more about marginalized sources and their communication strategies we know relatively little about those of powerful multinational corporate organizations, governments and lobby groups. The shifting media environment and the networked nature of information demand a major rethinking of early media-centric approaches to examining journalist/source relations as applied to climate change. The metaphors of ‘network’ and field’ capture the diverse linkages across different spheres better than the Hierarchy of Influences model.

Article

Christopher K. Wikle

The climate system consists of interactions between physical, biological, chemical, and human processes across a wide range of spatial and temporal scales. Characterizing the behavior of components of this system is crucial for scientists and decision makers. There is substantial uncertainty associated with observations of this system as well as our understanding of various system components and their interaction. Thus, inference and prediction in climate science should accommodate uncertainty in order to facilitate the decision-making process. Statistical science is designed to provide the tools to perform inference and prediction in the presence of uncertainty. In particular, the field of spatial statistics considers inference and prediction for uncertain processes that exhibit dependence in space and/or time. Traditionally, this is done descriptively through the characterization of the first two moments of the process, one expressing the mean structure and one accounting for dependence through covariability. Historically, there are three primary areas of methodological development in spatial statistics: geostatistics, which considers processes that vary continuously over space; areal or lattice processes, which considers processes that are defined on a countable discrete domain (e.g., political units); and, spatial point patterns (or point processes), which consider the locations of events in space to be a random process. All of these methods have been used in the climate sciences, but the most prominent has been the geostatistical methodology. This methodology was simultaneously discovered in geology and in meteorology and provides a way to do optimal prediction (interpolation) in space and can facilitate parameter inference for spatial data. These methods rely strongly on Gaussian process theory, which is increasingly of interest in machine learning. These methods are common in the spatial statistics literature, but much development is still being done in the area to accommodate more complex processes and “big data” applications. Newer approaches are based on restricting models to neighbor-based representations or reformulating the random spatial process in terms of a basis expansion. There are many computational and flexibility advantages to these approaches, depending on the specific implementation. Complexity is also increasingly being accommodated through the use of the hierarchical modeling paradigm, which provides a probabilistically consistent way to decompose the data, process, and parameters corresponding to the spatial or spatio-temporal process. Perhaps the biggest challenge in modern applications of spatial and spatio-temporal statistics is to develop methods that are flexible yet can account for the complex dependencies between and across processes, account for uncertainty in all aspects of the problem, and still be computationally tractable. These are daunting challenges, yet it is a very active area of research, and new solutions are constantly being developed. New methods are also being rapidly developed in the machine learning community, and these methods are increasingly more applicable to dependent processes. The interaction and cross-fertilization between the machine learning and spatial statistics community is growing, which will likely lead to a new generation of spatial statistical methods that are applicable to climate science.

Article

Global climate models are our main tool to generate quantitative climate projections, but these models do not resolve the effects of complex topography, regional scale atmospheric processes and small-scale extreme events. To understand potential regional climatic changes, and to provide information for regional-scale impact modeling and adaptation planning, downscaling approaches have been developed. Regional climate change modeling, even though it is still a matter of basic research and questioned by many researchers, is urged to provide operational results. One major downscaling class is statistical downscaling, which exploits empirical relationships between larger-scale and local weather. The main statistical downscaling approaches are perfect prog (often referred to as empirical statistical downscaling), model output statistics (which is typically some sort of bias correction), and weather generators. Statistical downscaling complements or adds to dynamical downscaling and is useful to generate user-tailored local-scale information, or to efficiently generate regional scale information about mean climatic changes from large global climate model ensembles. Further research is needed to assess to what extent the assumptions underlying statistical downscaling are met in typical applications, and to develop new methods for generating spatially coherent projections, and for including process-understanding in bias correction. The increasing resolution of global climate models will improve the representation of downscaling predictors and will, therefore, make downscaling an even more feasible approach that will still be required to tailor information for users.

Article

The importance of framing as a concept is reflected by the massive amount of attention it has received from scholars across disciplines. As a communicative process, framing involves making certain considerations salient as a way to simplify or shape the way in which an audience understands a particular problem and its potential solutions. As recently as the early 2000s, social scientists began to examine how strategic frames in a communication affect both individuals’ beliefs about climate change and the actions they are willing to support to mitigate the likely effects. Research on the effects of how strategic frames influence the attitudes, beliefs, and preferences of individuals in this domain primarily builds on insights from framing theory, which explains that an individual’s attitude or preference in any given context depends on the available, accessible, and most applicable (i.e., perceived strongest) considerations. But it is much more than theory: frames related to the effects and potential solutions for climate change have been employed strategically by various actors in an effort to shape public opinion and public policy. Perceptions of scientific consensus on climate change are thought to play an important role in determining support for policy actions. Consequently, strategic actors promote a particular agenda by accentuating the inherent uncertainty of climate science, thus casting doubt on the scientific consensus. This has contributed to partisan polarization on climate change and the rise of protective forms of information processing and reasoning in this domain. Strategic messages and frames that resonate with particular subgroups have no effect, or may even backfire, on other segments of the population. Additionally, as individuals who possess different partisan identities become more knowledgeable and numerate, they become increasingly likely to accept information and messages that bolster their existing group loyalties and to reject communications that challenge those identities. Science communicators are thus presented with a considerable barrier to building consensus among the public for action on climate change. In response, scholars have begun to identify strategies and approaches for addressing audiences with the kinds of messages that are most likely to resonate with individuals possessing a diverse range of values and political identities. Further research must identify ways to overcome partisan motivated reasoning on climate change and the persistent and deleterious effects that have resulted from the politicization of climate science.

Article

Misperceptions about climate change are widespread, and efforts to correct them must be grounded in an understanding of the factors, both individual and social, that contribute to them. These factors can be organized into four broad categories: motivated reasoning, non-motivated information processing biases, social dynamics, and the information environment. Each type of factor is associated with a host of related strategies for countering false information and beliefs. Motivated biases can be reduced with affirmations, by attempting to depoliticize the issue, and via an evidentiary “tipping point.” Other cognitive biases highlight the importance of clarity, simplicity, and repetition. When correcting errors that contain an inaccurate causal explanation, it is also important to provide an alternative account of the event in question. Message presentation techniques can also facilitate updating beliefs. Beliefs have an important social dimension. Attending to these factors shows the importance of strategies that include: ensuring that lay people consistently have the tools that help them evaluate experts; promoting confidence among those who hold accurate beliefs; facilitating diverse, unsegregated social networks; and providing corrections from unexpected sources. Finally, the prevalence of misinformation in the information environment is highly problematic. Strategies that news organizations can employ include avoiding false balance, adjudicating among contradictory claims, and encouraging accuracy on the part of political elites via fact checking. New technologies may also prove an important tool: search engines that give preferential treatment to accurate information and automated recommendations of accurate information following exposure to inaccuracies both have the potential to change how individuals learn about climate change.

Article

Judith L. Lean

Emergent in recent decades are robust specifications and understanding of connections between the Sun’s changing radiative energy and Earth’s changing climate and atmosphere. This follows more than a century of contentious debate about the reality of such connections, fueled by ambiguous observations, dubious correlations, and lack of plausible mechanisms. It derives from a new generation of observations of the Sun and the Earth made from space, and a new generation of physical climate models that integrate the Earth’s surface and ocean with the extended overlying atmosphere. Space-based observations now cover more than three decades and enable statistical attribution of climate change related to the Sun’s 11-year activity cycle on global scales, simultaneously with other natural and anthropogenic influences. Physical models that fully resolve the stratosphere and its embedded ozone layer better replicate the complex and subtle processes that couple the Sun and Earth. An increase of ~0.1% in the Sun’s total irradiance, as observed near peak activity during recent 11-year solar cycles, is associated with an increase of ~0.1oC in Earth’s global surface temperature, with additional complex, time-dependent regional responses. The overlying atmosphere warms more, by 0.3oC near 20 km. Because solar radiation impinges primarily at low latitudes, the increased radiant energy alters equator-to-pole thermal gradients, initiating dynamical responses that produce regions of both warming and cooling at mid to high latitudes. Because solar energy deposition depends on altitude as a result of height-dependent atmospheric absorption, changing solar radiation establishes vertical thermal gradients that further alter dynamical motions within the Earth system. It remains uncertain whether there are long-term changes in solar irradiance on multidecadal time scales other than due to the varying amplitude of the 11-year cycle. If so the magnitude of the additional change is expected to be comparable to that observed during the solar activity cycle. Were the Sun’s activity to become anomalously low, declining during the next century to levels of the Maunder Minimum (from 1645 to 1715), the expected global surface temperature cooling is less than a few tenths oC. In contrast, a scenario of moderate greenhouse gas increase with climate forcing of 2.6 W m−2 over the next century is expected to warm the globe 1.5 to 1.9oC, an order of magnitude more than the hypothesized solar-induced cooling over the same period. Future challenges include the following: securing sufficiently robust observations of the Sun and Earth to elucidate changes on climatological time scales; advancing physical climate models to simulate realistic responses to changing solar radiation on decadal time scales, synergistically at the Earth’s surface and in the ocean and atmosphere; disentangling the Sun’s influence from that of other natural and anthropogenic influences as the climate and atmosphere evolve; projecting past and future changes in the Sun and Earth’s climate and atmosphere; and communicating new understanding across scientific disciplines, and to political and societal stakeholders.

Article

Direct experience, scientific reports, and international media coverage make clear that the breadth, severity, and multiple consequences from climate change are far-reaching and increasing. Like many places globally, the northeastern United States is already experiencing climate change, including one of the world’s highest rates of ocean warming, reduced durations of winter ice cover on lakes, a marked increase in the frequency of extreme precipitation events, and climate-mediated ecological disruptions of invasive species. Given current and projected changes in ecosystems, communities, and economies, it is essential to find ways to anticipate and reduce vulnerabilities to change and, at the same time, promote sustainable economic development and human well-being. The emerging field of sustainability science offers a promising conceptual and analytic framework for accelerating progress towards sustainable development. Sustainability science aims to be use-inspired and to connect basic and applied knowledge with solutions for societal benefit. This approach draws from diverse disciplines, theories, and methods organized around the broad goal of maintaining and improving life support systems, ecosystem health, and human well-being. Partners in New England have been using sustainability science as a framework for stakeholder-engaged, interdisciplinary research that has generated use-inspired knowledge and multiple solutions for more than a decade. Sustainability science has helped produce a landscape-scale approach to wetland conservation; emergency response plans for invasive species that threaten livelihoods and cultures; decision support tools for improved water quality management and public health for beach use and shellfish consumption; and the development of robust partnership networks across disciplines and institutions. Understanding and reducing vulnerability to climate change is a central motivating factor in this portfolio of projects because linking knowledge about social-ecological systems with effective policy action requires a holistic view that addresses complex intersecting stressors. One common theme in these varied efforts is the way that communication fundamentally shapes collaborative research and social, technical, and policy outcomes from sustainability science. Communication as a discipline has, for more than two thousand years, sought to understand how environments and symbols shape human life, forms of social organization, and collective decision making. The result is a body of scholarship and practical techniques that are diverse and well adapted to meet the complexity of contemporary sustainability challenges. The complexity of the issues that sustainability science aspires to solve requires diversity and flexibility to be able to adapt approaches to the specific needs of a situation. Long-term, cross-scale, and multi-institutional sustainability science collaborations show that communication research and practice can help build communities and networks, and advance technical and policy solutions to confront the challenges of climate change and promote sustainability now and in future.

Article

Rainfall over Africa varies across timescales of a few days to several weeks due to several tropical and extratropical modes of variability. Excessive rains or prolonged drought regularly result in natural disasters and have thus a severe impact on the local economy, agriculture, spread of diseases, and entire ecosystems. The dynamical nature of the atmosphere allows the existence of planetary balanced modes, which are called Rossby waves, and smaller-scale unbalanced inertio-gravity (IG) waves. The former, which are more rotational, arise from the horizontal pressure gradient force, while for the latter gravity acts as the restoring force, making their flow pattern more divergent. The main source of variability in the extratropics stems from Rossby waves. At the equator, further types of convectively coupled equatorial waves (CCEWs) exist, namely Kelvin and mixed Rossby-gravity (MRG) waves. As the slowest intraseasonal tropical mode, the Madden–Julian Oscillation (MJO), which is related to Kelvin and Rossby waves, acts on a timescale of 30 to 90 days. Although it is primarily a planetary mode, the MJO has a specific “flavor” over the African continent. On the short intraseasonal timescale of 10 to 25 days, equatorial Rossby (ER) waves and the internal modes of the West African monsoon, the quasi-biweekly zonal dipole (QBZD) and the Sahel mode, modulate rainfall. On the synoptic timescale of a few days to a week, African easterly waves (AEWs) are a dominant mode over West Africa, whereas Kelvin waves predominantly modulate rainfall over equatorial Africa. Extratropical influences on northern and southern Africa manifest themselves in Rossby wave trains, which modulate synoptic to intraseasonal rainfall through tropical rainfall plumes, cold air surges, and upper-tropospheric dry air intrusions. Furthermore, the Saharan heat low (SHL) acts as a link between the northern hemispheric extratropics and tropics. Finally, the Indian monsoon, the Atlantic, Indian, and the Pacific Oceans can remotely affect the intraseasonal variability of African rainfall. Forecasting synoptic to intraseasonal rainfall variability is an integral part of seamless prediction between the weather and climate regimes. In the early 21st century, numerical weather prediction (NWP) systems can forecast larger intraseasonal signals such as the MJO several weeks into the future, but they still struggle to forecast shorter scale features reliably. Besides NWP, statistical models can successfully forecast intraseasonal variability of rainfall. Due to the relevance of synoptic to intraseasonal rainfall variability for African societies, early warning systems (EWSs) have been developed to mitigate impacts.

Article

The East African Rift System (EARS) transecting the high-elevation East African plateau is one of the most outstanding rift systems on earth. Rifting was caused by a huge uprising mantle plume under East Africa. Two distinct rift branches are distinguished: an older, volcanically very active Eastern Branch and a younger, much less volcanic Western Branch. The Eastern Branch is generally characterized by high elevation, whereas the Western Branch comprises a number of deep rift lakes (e.g., Lake Tanganyika, Lake Malaŵi). These differences reflect different plate strengths, the latter of which are largely governed by differences in how the mantle plume interacted with the East African lithosphere. Much of the topography forming the East African plateau has been caused by the uprising mantle plume. The onset of topographic uplift in the EARS is poorly dated but preceded graben development, the latter of which commenced at ~24 Ma in the Ethiopian Rift, at ~12 Ma in Kenya, and at ~10 Ma in the Western Branch. Increased uplift of the East African plateau since ~15–10 Ma might be connected to climate change in East Africa and human evolution. East Africa experienced cooling starting at 15.5–12.5 Ma that heralded profound faunal changes at 8–5 Ma, when the hominin lineage split from the chimpanzee lineage. The Pliocene is characterized by warm and wet climate between 5.3 and 3.3 Ma transitioning into a period of cooler and more arid conditions after ~3 Ma. The climate in the EARS is controlled by westerly monsoonal flow over equatorial West Africa and easterly monsoonal flow over the Indian Ocean. The uplifting East African plateau intercepted those winds and contributed to the increased aridification of East Africa.

Article

The term “teleconnection” in climate studies was defined primarily for widely separated regions. This stems from the basic idea that a physical process, such as an advection or a particular synoptic system, cannot simply explain a relation or a correlation in large distances. Also, in modern times, models more often fail in predicting these remote patterns, particularly with regional models. Even with a clear physical process of advection and for a short horizontal scale, teleconnection is often not well understood if the physical mechanism involved is complex, such as in the subsynoptic scales of aerosol–rainfall interaction or megacities and their potential effects on precipitation. Thus, in a broader view of the horizontal scale of teleconnection, the word “tele” still represents the word “far,” as in its Greek origin, but it also includes the limitation in understanding complex atmospheric relations in various distances. Furthermore, the hidden assumption that ancients were not able to observe teleconnections is contradicted by an example from approximately 1,800 years ago. In this example, a claim was made in the Talmud that the Euphrates flow is strongly related to the rainfall over the greater Israel region, located approximately 700–900 km westward. However, the understanding of this ancient teleconnection was only possible in the second half of the 19th century when the role of synoptic systems in weather emerged.

Article

Nathalie de Noblet-Ducoudré and Andrew J. Pitman

The land surface is where humans live and where they source their water and food. The land surface plays an important role in climate and anthropogenic climate change both as a driver of change and as a system that responds to change. Soils and vegetation influence the exchanges of water, energy and carbon between the land and the overlying atmosphere and thus contribute to the variability and the evolution of climate. But the role of the land in climate is scale dependent which means different processes matter on different timescales and over different spatial scales. Climate change alters the functioning of the land with changes in the seasonal cycle of ecosystem growth, in the extent of forests, the melt of permafrost, the magnitude and frequency of disturbances such as fire, drought, … Those changes feedback into climate at both the global and the regional scales. In addition, humans perturb the land conditions via deforestation, irrigation, urbanization, … and this directly affects climatic conditions at the local to regional scales with also sometimes global consequences via the release of greenhouse gases. Not accounting for land surface processes in climate modelling, whatever the spatial scale, will result in biases in the climate simulations.

Article

Deborah R. Coen

The advent of climate science can be defined as the historical emergence of a research program to study climate according to a modern definition of climate. Climate in this sense: (1) refers not simply to the average state of the atmosphere but also to its variability; (2) is multiscalar, concerned with phenomena ranging from the very small and fast to the very large and slow; and (3) is understood to be influenced by the oceans, lithosphere, cryosphere, and biosphere. Most accounts of the history of climate science to date have focused on the development of computerized general circulation models since World War Two. However, following this definition, the advent of climate science occurred well before the computer age. This entry therefore seeks to dispel the image of climate science as a recent invention and as the preserve of an exclusive, North American elite. The historical roots of today’s knowledge of climate change stretch surprisingly far back into the past and clear across the world, though the geographic focus here is on Europe and North America. The modern science of climate emerged out of interactions between learned and vernacular knowledge traditions, and has simultaneously appropriated and undermined traditional and indigenous forms of climate knowledge. Important precedents emerged in the 17th and 18th centuries, and it was in the late 19th century that a modern science of climate coalesced into a coordinated research program in part through the unification of divergent knowledge traditions around standardized techniques of measurement and analysis.

Article

Wilfried Haeberli, Johannes Oerlemans, and Michael Zemp

Like many comparable mountain ranges at lower latitudes, the European Alps are increasingly losing their glaciers. Following roughly 10,000 years of limited climate and glacier variability, with a slight trend of increasing glacier sizes to Holocene maximum extents of the Little Ice Age, glaciers in the Alps started to generally retreat after 1850. Long-term observations with a monitoring network of unique density document this development. Strong acceleration of mass losses started to take place after 1980 as related to accelerating atmospheric temperature rise. Model calculations, using simple to high-complexity approaches and relating to individual glaciers as well as to large samples of glaciers, provide robust results concerning scenarios for the future: under the influence of greenhouse-gas forced global warming, glaciers in the Alps will largely disappear within the 21st century. Anticipating and modeling new landscapes and land-forming processes in de-glaciating areas is an emerging research field based on modeled glacier-bed topographies that are likely to become future surface topographies. Such analyses provide a knowledge basis to early planning of sustainable adaptation strategies, for example, concerning opportunities and risks related to the formation of glacial lakes in over-deepened parts of presently still ice-covered glacier beds.