The Basin of Mexico is a key world region for understanding agricultural intensification and the development of ancient and historic cities and states. Archaeologists working in the region have had a long-standing interest in understanding the dynamics of interactions between society and environment and their research has been at the forefront of advances in both method and theory. The Basin of Mexico was the geopolitical core of the Aztec empire, the largest state in the history of Mesoamerica. Its growth was sustained by a complex economy that has been the subject of much research. Two themes underlie a broad interest in the pre-Hispanic agriculture of the Basin of Mexico. First, how with a Neolithic technology did the Aztecs and their predecessors sustain the growth of large cites, dense rural populations, and the largest state system in the history of pre-Hispanic Mesoamerica? Second, what is the relationship of agricultural intensification and urbanization and state formation? Mesoamerica is the only world region where primary civilizations developed that lacked domestic herbivores for either food or transportation. Their farming depended entirely on human labor and hand tools but sustained large cities, dense populations, and complex social institutions. Intensive agriculture began early and was promoted by risk, ecological diversity, and social differentiation, and included irrigation, terracing, and drained fields (chinampas). Most farming was managed by smallholder households and local communities, which encouraged corporate forms of governance and collective action. Environmental impacts included erosion and deposition, but were limited compared with the degradation that took place in the colonial period.
Deborah L. Nichols
Aijun Ding, Xin Huang, and Congbin Fu
Air pollution is one of the grand environmental challenges in developing countries, especially those with high population density like China. High concentrations of primary and secondary trace gases and particulate matter (PM) are frequently observed in the industrialized and urbanized regions, causing negative effects on the health of humans, plants, and the ecosystem. Meteorological conditions are among the most important factors influencing day-to-day air quality. Synoptic weather and boundary layer dynamics control the dispersion capacity and transport of air pollutants, while the main meteorological parameters, such as air temperature, radiation, and relative humidity, influence the chemical transformation of secondary air pollutants at the same time. Intense air pollution, especially high concentration of radiatively important aerosols, can substantially influence meteorological parameters, boundary layer dynamics, synoptic weather, and even regional climate through their strong radiative effects. As one of the main monsoon regions, with the most intense human activities in the world, East Asia is a region experiencing complex air pollution, with sources from anthropogenic fossil fuel combustion, biomass burning, dust storms, and biogenic emissions. A mixture of these different plumes can cause substantial two-way interactions and feedbacks in the formation of air pollutants under various weather conditions. Improving the understanding of such interactions needs more field measurements using integrated multiprocess measurement platforms, as well as more efforts in developing numerical models, especially for those with online coupled processes. All these efforts are very important for policymaking from the perspectives of environmental protection and mitigation of climate change.
Johanna Brühl, Leonard le Roux, Martine Visser, and Gunnar Köhlin
The water crisis that gripped Cape Town over the 2016–2018 period gained global attention. For a brief period of time in early 2018, it looked as if the legislative capital of South Africa would become the first major city in the world to run out of water. The case of Cape Town has broad implications for how we think about water management in a rapidly urbanizing world. Cities in the global South, especially, where often under-capacitated urban utilities need to cope with rapid demographic changes, climate change, and numerous competing demands on their tight budgets, can learn from Cape Town’s experience. The case of Cape Town draws attention to the types of decisions policymakers and water utilities face in times of crisis. It illustrates how these decisions, while being unavoidable in the short term, are often sub-optimal in the long run. The Cape Town drought highlights the importance of infrastructure diversification, better groundwater management, and communication and information transparency to build trust with the public. It also shows what governance and institutional changes need to be made to ensure long-term water security and efficient water management. The implementation of all of these policies needs to address the increased variability of water supplies due to increasingly erratic rainfall and rapidly growing urban populations in many countries. This necessitates a long-term planning horizon.
Ecotourism is responsible travel to natural areas that educates and inspires through interpretation—increasingly paired with practical action—that helps conserve the environment and sustain the well-being of local people. Ecotourism is the fastest-growing segment of the travel and tourism industry, and its economic value is projected to exceed USD$100 billion by 2027. Ecotourism emerged in the 1960s as a response to the destructive effects of mass tourism and has been embraced by an increasing number of governments, especially in the developing world, as a vehicle for achieving the UN Sustainable Development Goals. As an emerging, interdisciplinary field of study, ecotourism has reached a critical inflection point, as scholars reflect on the achievements and shortcomings of several decades of research and set out the research agenda for decades to come. The field has yet to achieve consensus on the most basic questions, such as how ecotourism is, or should be, defined; what makes it different from nature-based and related forms of tourism; and what factors ultimately determine the success or failure of ecotourism as a vehicle for sustainable development. This lack of consensus stems in part from the different perspectives and agendas within and between the academic, policy, and industry communities. Because it is based on measured and observed phenomena, empirical research has a critical role to play in advancing the theory and practice of ecotourism. However, scholars also recognize that to fulfill this role, methodologies must evolve to become more longitudinal, scalable, inclusive, integrative, and actionable.
Simon Holdaway and Rebecca Phillipps
Northeast Africa forms an interesting case study for investigating the relationship between changes in environment and agriculture. Major climatic changes in the early Holocene led to dramatic changes in the environment of the eastern Sahara and to the habitation of previously uninhabitable regions. Research programs in the eastern Sahara have uncovered a wealth of archaeological evidence for sustained occupation during the African Humid Period, from about 11,000 years ago. Initial studies of faunal remains seemed to indicate early shifts in economic practice toward cattle pastoralism. Although this interpretation was much debated when it was first proposed, the possibility of early pastoralism stimulated discussion concerning the relationships between people and animals in particular environmental contexts, and ultimately led to questions concerning the role of agriculture imported from elsewhere in contrast to local developments. Did agriculture, or indeed cultivation and domestication more generally (sensu Fuller & Hildebrand, 2013), develop in North Africa, or were the concepts and species imported from Southwest Asia? And if agriculture did spread from elsewhere, were just the plants and animals involved, or was the shift part of a full socioeconomic suite that included new subsistence strategies, settlement patterns, technologies, and an agricultural “culture”? And finally, was this shift, wherever and however it originated, related to changes in the environment during the early to mid-Holocene? These questions refer to the “big ideas” that archaeologists explore, but before answers can be formed it is important to consider the nature of the material evidence on which they are based. Archaeologists must consider not only what they discover but also what might be missing. Materials from the past are preserved only in certain places, and of course some materials can be preserved better than others. In addition, people left behind the material remains of their activities, but in doing so they did not intend these remains to be an accurate historical record of their actions. Archaeologists need to consider how the remains found in one place may inform us about a range of activities that occurred elsewhere for which the evidence may be less abundant or missing. This is particularly true for Northeast Africa where environmental shifts and consequent changes in resource abundance often resulted in considerable mobility. This article considers the origins of agriculture in the region covering modern-day Egypt and Sudan, paying particular attention to the nature of the evidence from which inferences about past socioeconomies may be drawn.
Isabela Espindola and Pilar Villar
The sharing of transboundary water resources, whether surface or groundwater, is a significant challenge, both in theory and practice. Countries in situations of sharing these natural resources are predisposed to interact with each other. These interactions, here called transboundary water interactions, are characterized by the coexistence of cooperation and conflict, which can arise at different governance levels. However, negotiations around transboundary water resources primarily occur between diplomats and high government members from riparian countries and river basin organization (RBO) managers. Transboundary water negotiations are usually considered high-level political discussions, given the complexity and scale of the water challenges. Consequently, decision-making processes incorporate only a limited number of participants, who make decisions capable of impacting the entire population that depend on the shared waters. Over the last 20 years, there has been a need for greater transparency and a participatory process in transboundary water negotiations, especially for local community engagement and collaboration in these processes. Many of the negotiation processes around transboundary water resources need the participation of municipalities and local populations, concomitant with the involvement of RBOs, to carry out decisions to manage transboundary waters in an integrated manner. There are several reasons for this demand, including negotiation effectiveness, contestation prevention, data sharing, ensuring continuing participation and collaboration, and promoting public awareness related to water resources. Discussing social participation, particularly in the management of transboundary water resources, requires attention to the historical context and its constraints. Considering the enormous challenge, the experiences of local community engagement in transboundary water negotiations in South America, especially from the Guarani Aquifer and the La Plata Basin, are good examples for improving this discussion around transboundary water interactions and local community engagement. The La Plata Basin is the second-largest transboundary basin in the continent, shared by Argentina, Bolivia, Brazil, Uruguay, and Paraguay, while the Guarani Aquifer is one of the largest reservoirs of freshwater worldwide, shared by Argentina, Brazil, Paraguay, and Uruguay. Even with both having cooperation agreements in place between the riparian states, there are still great difficulties with regard to the participation of local communities in transboundary water negotiations.
Robert B. Richardson
Sustainable development is the foundational principle for enhancing human and economic development while maintaining the functional integrity of ecological and social systems that support regional economies. Tourism has played a critical role in sustainable development in many countries and regions around the world. In developing countries, tourism development has been used as an important strategy for increasing economic growth, alleviating poverty, creating jobs, and improving food security. Many developing countries are in regions that are characterized by high levels of biological diversity, natural resources, and cultural heritage sites that attract international tourists whose local purchases generate income and support employment and economic development. Tourism has been associated with the principles of sustainable development because of its potential to support environmental protection and livelihoods. However, the relationship between tourism and the environment is multifaceted, as some types of tourism have been associated with negative environmental impacts, many of which are borne by host communities. The concept of sustainable tourism development emerged in contrast to mass tourism, which involves the participation of large numbers of people, often in structured or packaged tours. Mass tourism has been associated with economic leakage and dependence, along with negative environmental and social impacts. Sustainable tourism development has been promoted in various ways as a framing concept in contrast to these economic, environmental, and social impacts. Some literature has acknowledged a vagueness of the concept of sustainable tourism, which has been used to advocate for fundamentally different strategies for tourism development that may exacerbate existing conflicts between conservation and development paradigms. Tourism has played an important role in sustainable development in some countries through the development of alternative tourism models, including ecotourism, community-based tourism, pro-poor tourism, slow tourism, green tourism, and heritage tourism, among others that aim to enhance livelihoods, increase local economic growth, and provide for environmental protection. Although these models have been given significant attention among researchers, the extent of their implementation in tourism planning initiatives has been limited, superficial, or incomplete in many contexts. The sustainability of tourism as a global system is disputed among scholars. Tourism is dependent on travel, and nearly all forms of transportation require the use of non-renewable resources such as fossil fuels for energy. The burning of fossil fuels for transportation generates emissions of greenhouse gases that contribute to global climate change, which is fundamentally unsustainable. Tourism is also vulnerable to both localized and global shocks. Studies of the vulnerability of tourism to localized shocks include the impacts of natural disasters, disease outbreaks, and civil unrest. Studies of the vulnerability of tourism to global shocks include the impacts of climate change, economic crisis, global public health pandemics, oil price shocks, and acts of terrorism. It is clear that tourism has contributed significantly to economic development globally, but its role in sustainable development is uncertain, debatable, and potentially contradictory.
Maria Cristina Fossi and Cristina Panti
A vigorous effort to identify and study sentinel species of marine ecosystem in the world’s oceans has developed over the past 50 years. The One Health concept recognizes that the health of humans is connected to the health of animals and the environment. Species ranging from invertebrate to large marine vertebrates have acted as “sentinels” of the exposure to environmental stressors and health impacts on the environment that may also affect human health. Sentinel species can signal warnings, at different levels, about the potential impacts on a specific ecosystem. These warnings can help manage the abiotic and anthropogenic stressors (e.g., climate change, chemical and microbial pollutants, marine litter) affecting ecosystems, biota, and human health. The effects of exposure to multiple stressors, including pollutants, in the marine environment may be seen at multiple trophic levels of the ecosystem. Attention has focused on the large marine vertebrates, for several reasons. In the past, the use of large marine vertebrates in monitoring and assessing the marine ecosystem has been criticized. The fact that these species are pelagic and highly mobile has led to the suggestion that they are not useful indicators or sentinel species. In recent years, however, an alternative view has emerged: when we have a sufficient understanding of differences in species distribution and behavior in space and time, these species can be extremely valuable sentinels of environmental quality. Knowledge of the status of large vertebrate populations is crucial for understanding the health of the ecosystem and instigating mitigation measures for the conservation of large vertebrates. For example, it is well known that the various cetacean species exhibit different home ranges and occupy different habitats. This knowledge can be used in “hot spot” areas, such as the Mediterranean Basin, where different species can serve as sentinels of marine environmental quality. Organisms that have relatively long life spans (such as cetaceans) allow for the study of chronic diseases, including reproductive alterations, abnormalities in growth and development, and cancer. As apex predators, marine mammals feed at or near the top of the food chain. As the result of biomagnification, the levels of anthropogenic contaminants found in the tissues of top predators and long-living species are typically high. Finally, the application of consistent examination procedures and biochemical, immunological, and microbiological techniques, combined with pathological examination and behavioral analysis, has led to the development of health assessment methods at the individual and population levels in wild marine mammals. With these tools in hand, investigators have begun to explore and understand the relationships between exposures to environmental stressors and a range of disease end points in sentinel species (ranging from invertebrates to marine mammals) as an indicator of ecosystem health and a harbinger of human health and well-being.