An orbitally induced increase in summer insolation during the last glacial-interglacial transition enhanced the thermal contrast between land and sea, with land masses heating up compared to the adjacent ocean surface. In North Africa, warmer land surfaces created a low-pressure zone, driving the northward penetration of monsoonal rains originating from the Atlantic Ocean. As a consequence, regions today among the driest of the world were covered by permanent and deep freshwater lakes, some of them being exceptionally large, such as the “Mega” Lake Chad, which covered some 400 000 square kilometers. A dense network of rivers developed.
What were the consequences of this climate change on plant distribution and biodiversity? Pollen grains that accumulated over time in lake sediments are useful tools to reconstruct past vegetation assemblages since they are extremely resistant to decay and are produced in great quantities. In addition, their morphological character allows the determination of most plant families and genera.
In response to the postglacial humidity increase, tropical taxa that survived as strongly reduced populations during the last glacial period spread widely, shifting latitudes or elevations, expanding population size, or both. In the Saharan desert, pollen of tropical trees (e.g., Celtis) were found in sites located at up to 25°N in southern Libya. In the Equatorial mountains, trees (e.g., Olea and Podocarpus) migrated to higher elevations to form the present-day Afro-montane forests. Patterns of migration were individualistic, with the entire range of some taxa displaced to higher latitudes or shifted from one elevation belt to another. New combinations of climate/environmental conditions allowed the cooccurrences of taxa growing today in separate regions. Such migrational processes and species-overlapping ranges led to a tremendous increase in biodiversity, particularly in the Saharan desert, where more humid-adapted taxa expanded along water courses, lakes, and wetlands, whereas xerophytic populations persisted in drier areas.
At the end of the Holocene era, some 2,500 to 4,500 years ago, the majority of sites in tropical Africa recorded a shift to drier conditions, with many lakes and wetlands drying out. The vegetation response to this shift was the overall disruption of the forests and the wide expansion of open landscapes (wooded grasslands, grasslands, and steppes). This environmental crisis created favorable conditions for further plant exploitation and cereal cultivation in the Congo Basin.
Bridie McGreavy and David Hart
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.
Student Perceptions, Textbook Presentations, and Communicating about Climate Change in the U.S. Science Classroom
Although future generations—starting with today’s youth—will bear the brunt of negative effects related to climate change, some research suggests that they have little concern about climate change nor much intention to take action to mitigate its impacts. One common explanation for this indifference and inaction is lack of scientific knowledge. It is often said that youth do not understand the science; therefore, they are not concerned. Indeed, in science educational research, numerous studies catalogue the many misunderstandings students have about climate science. However, this knowledge-deficit perspective is not particularly informative in charting a path forward for climate-change education. This path is important because climate science will be taught in more depth as states adopt the Next Generation Science Standards within the next few years. How do we go about creating the educational experiences that students need to be able to achieve climate-science literacy and feel as if they could take action? First, the literature base in communication, specifically about framing must be considered, to identify potentially more effective ways to craft personally relevant and empowering messages for students within their classrooms.
Oceanic mixing is one of the major determinants of the ocean circulation and its climatological influences. Existing distributions of mixing properties determine the rates of storage and redistribution within the climate system of fundamental scalar tracers including heat, fresh water, oxygen, carbon, and others. Observations have overturned earlier concepts that mixing rates might be approximately uniform throughout the ocean volume, with profound implications for determining the circulation and its properties. Inferences about past and potential future oceanic circulations and the resulting climate influence require determination of changed energy inputs and the expected consequent adjustment of mixing processes and their influence.
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.
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.
Luisa F. Lema Vélez, Daniel Hermelin, Margarita Fontecha, and Dunia H. Urrego
Colombia is in a privileged position to take advantage of international climate agreements to finance sustainable development initiatives. The country is a signatory of the United Nations Framework Convention on Climate Change (UNFCCC), the Kyoto Protocol, and the Paris Agreements. As a non-Annex I party to the UNFCCC, Colombia produces low emissions in relation to global numbers (0.46% of total global emissions for 2010) and exhibits biogeographical conditions that are ideal for mitigation of climate change through greenhouse gas sequestration and emission reductions. Simultaneously, recent extreme climatic events have harshly compromised the country’s economy, making Colombia’s vulnerability to climate change evident.
While these conditions should justify a strong approach to climate change communication that motivates decision making and leads to mitigation and adaptation, the majority of sectors still fall short of effectively communicating their climate change messages. Official information about climate change is often too technical and rarely includes a call for action. However, a few exceptions exist, including environmental education materials for children and a noteworthy recent strategy to deliver the Third Communication to the UNFCCC in a form that is more palatable to the general public. Despite strong research on climate change, particularly related to agricultural, environmental, and earth sciences, academic products are rarely communicated in a way that is easily understood by decision makers and has a clear impact on public policy. Messages from the mass media frequently confuse rather than inform the public. For instance, television news refers to weather-related disasters, climate variability, and climate change indiscriminately. This shapes an erroneous idea of climate change among the public and weakens the effectiveness of communications on the issue.
The authors contrast the practices of these sectors with those of nongovernmental organizations (NGOs) working in Colombia to show how they address the specific climate communication needs facing the country. These NGOs directly face the challenge of working with diverse population groups in this multicultural, multiethnic, and megadiverse country. NGOs customize languages, channels, and messages for different audiences and contexts, with the ultimate goal of building capacity in local communities, influencing policymakers, and sensitizing the private sector. Strategies that result from the work of interdisciplinary groups, involve feedback from the audiences, and incorporate adaptive management have proven to be particularly effective.
In equatorial East Africa, glaciers still exist on Mount Kenya, Kilimanjaro, and Ruwenzori. The decreasing ice extent has been documented by field reports since the end of the 19th century and a series of mappings. For Mount Kenya, the mappings are of 1947, 1963, 1987, 1993, and 2004, with more detailed mappings of Lewis Glacier in 1934, 1958, 1963, 1974, 1978, 1982, 1985, 1986, 1990, and 1993. For Kilimanjaro, the sequence is 1912, 1953, 1976, 1989, and 2000. For Ruwenzori (for which information is more scarce), the information is from 1906, 1955, and 1990. Photographs are valuable complementary evidence. At Lewis Glacier on Mount Kenya, measurements of mass budget and ice flow have been conducted over decades. The climatic forcing of ice recession in East Africa at the onset in the 1880s was radiationally controlled, affecting the most exposed locations. Later warming caused further ice shrinkage, except on the summit plateau of Kilimanjaro, above the freezing level. Whereas the ice recession in the Ecuadorian Andes and New Guinea began in the middle of the 19th century, plausibly caused by warming, the late onset in East Africa should be appreciated in the context of large-scale circulation changes evidenced by the historical ship observations in the equatorial Indian Ocean.
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.
Maria Ojala and Yuliya Lakew
One important group to include in efforts to combat climate change is young people. This group comprises the future leaders of society, besides being citizens of today, and they will be the ones handling the future negative consequences of this global problem. This article provides an overview of some research about climate change communication and young people. The aim is to gain a better understanding of how this group relates to and communicates about climate change in different contexts, and how to best promote knowledge, a sense of efficacy, and engagement concerning this problem. The focus is on young people who are between late childhood and young adulthood. Questions in focus are: How do media messages about climate change influence young people, and how do they themselves use media, for instance social networks, to engage with this issue? Can art-based and entertainment approaches to communication overcome the distant and complex character of climate change and make young people feel more empowered and engaged? Is it possible to communicate about climate change and raise awareness by promoting contact with nature and animals? How do young people cope with the negative emotions that are often evoked by information about this problem? In what way do young people communicate in everyday life with parents, peers, and teachers about climate change? Are participatory approaches to climate change communication a good way to prepare young people for future extreme climate events?