The use of fossil fuels in modern economies has been a success because of the low cost of fossil resources. However, the depletion of fossil reserves, the increase in waste production and global warming concerns have led to increased research on the production of biofuels from renewable resources. Waste production is steadily increasing in quantity and constantly changing in quality, creating enormous risks for the environment and, consequently, for the health of the population. This situation is much more worrying in developing countries, in particular because of the considerable delay in the field of the conversion and recovery of biomaterials, due to their difficulty in approaching the problem in a way that fits their context. The composition of such wastes and residues, rich in organic matter, allows their conversion via biochemical mechanisms, thus constituting an effective solution to address the environmental problems of their disposal. Anaerobic digestion remains a valuable and effective technology for transforming these biomaterials into biogas. The present review focuses on technologies, challenges and areas of application of biogas, especially in China and some African countries, in order to promote the large-scale use of biogas for electricity generation and biofuels. Results point out that China is more used to this technology, while African countries still rely on traditional and less advanced technologies, thus hampering the potential derived from the large availability of biomaterials. Both realities, however, share similar backgrounds about the dimension of the biogas plants and their non-commercial purposes, even if China is recently shifting toward the adoption of a different model. These considerations are used in the article to open an interesting new scenario of political alternatives which may provide a way out from poverty and economic dependence, within the framework of a wider circularity.

Global change, population growth, and urbanization have been exerting a severe influence on the environment, including the social system and ecosystem. To find solutions based on nature, clarifying the complicated mechanisms and feedback among land use/land cover changes, ecosystem services, and human well-being, is increasingly crucial. However, the in-depth linkages among these three elements have not been clearly and systematically illustrated, present research paths have not been summarized well, and the future research trends on this topic have not been reasonably discussed. In this sense, the purpose of this paper is to provide an insight into how land use/land cover changes, ecosystem services, and human well-being are linked, as well as their relationships, interacting ways, applications in solving ecological and socioeconomic problems, and to reveal their future research trends. Here, we use a systematic literature review of the peer-reviewed literature to conclude the state of the art and the progress, emphasize the hotspot, and reveal the future trend of the nexus among the three aspects. Results show that (1) ecosystem services are generally altered by the changes in land use type, spatial pattern, and intensity; (2) the nexus among land use change, ecosystem services, and human well-being is usually used for supporting poverty alleviation, ecosystem health, biodiversity conservation, and sustainable development; (3) future research on land use/land cover changes, ecosystem services, and human well-being should mainly focus on strengthening multiscale correlation, driving force analysis, the correlation among different group characteristics, land use types and ecosystem service preferences, and the impact of climate change on ecosystem services and human well-being. This study provides an enhanced understanding of the nexus among the three aspects and a reference for future studies to mitigate the relevant problems.