Land degradation is more evident where conditions of environmental vulnerability already exist because of arid climate and unsustainable forms of land exploitation. Consequently, semi-arid and dry areas have been identified as vulnerable land, requiring attention from both science and policy perspectives. In some regions, such as the Mediterranean region, land degradation is particularly intense, although there are no extreme ecological conditions. In these contexts, a wide range of formal and informal responses is necessary to face particularly complex and spatially differentiated territorial processes. However, the fit of responses has been demonstrated to be different over time and space according to the underlying socioeconomic context and the specific ecological conditions. The present commentary discusses this sort of “entropy” in the policy response to land degradation in Southern Europe, outlining the intrinsic complexity of human–nature dynamics at the base of such processes. Reflecting the need of differentiated regional strategies and more specific national measures to combat desertification, three policy frameworks (agro-environmental, economic, social) with an indirect impact on fighting land degradation have been considered, delineating the importance of policy assemblages. Finally, the importance of policy impact assessment methodologies was highlighted, focusing on the possible responses reinforcing a continental strategy against land degradation. By evidencing the role of participatory planning, developmental policies indirectly addressing land degradation reveal to be an important vector of more specific measures abating desertification risk, creating, in turn, a favorable context for direct interventions of mitigation or adaptation to climate change.

A diverse topography along with deforestation, changing climatic conditions, long-term human settlement, overuse of agricultural lands without sustainable planning, cultural difficulties in accepting conservative land management practices, and wrong political decisions have increased the vulnerability of many soils to degradation and resulted in a serious decline in their functional capacity. A progressive reduction in the capacity of soils to support plant productivity is not only a threat in the African continent and its large desert zone, but also in several parts of Central and Southeastern Europe (CASEE). The loss of soil functions throughout CASEE is mainly related to the human activities that have profound influence on soil dynamic characteristics. Improper management of soils has made them more vulnerable to degradation through water and wind erosion, organic matter depletion, salinity, acidification, crusting and sealing, and compaction. Unmitigated degradation has substantial implications for long term sustainability of the soils’ capability to support human communities and resist desertification. If sustainable agricultural and land management practices are not identified, well understood and implemented, the decline in soil quality will continue and probably accelerate. The lack of uniform criteria for the assessment and evaluation of soil quality in CASEE countries prevents scientific assessments to determine if existing management practices are leading to soil quality improvement, or if not, what management practices should be recommended to mitigate and reverse the loss of soil health.

Hyperarid, arid, semiarid, and dry subhumid areas cover approximately 41% of the global land area. The human population in drylands, currently estimated at 2.7 billion, faces limited access to sufficient, affordable, and nutritious food. We discuss the interlinkages among water security, environmental security, energy security, economic security, health security, and food security governance, and how they affect food security in drylands. Reliable and adequate water supply, and the prevention of water contamination, increase the potential for ample food, fodder, and fiber production. Protecting woodlands and rangelands increases food security by buffering the slow onset effects of climate change, including biodiversity loss, desertification, salinization, and land degradation. The protection of natural lands is expected to decrease environmental contamination, and simultaneously, reduce the transfer of diseases from wildlife to humans. Biofuel production and hydroelectric power plants increase energy security but generate land-use conflicts, deforestation, and ecosystem degradation. Economic security generally positively correlates with food security. However, economic growth often degrades the environment, changes tenure rights over natural resources, and stimulates migration to urban areas, resulting in lower food and health security. Moreover, civil unrest, political instability, and armed conflicts disrupt local economies in drylands. Maintaining food security is crucial for health security; conversely, malnourished populations and unresponsive health systems decrease economic security, and adversely affect environmental, energy, and food security. Climate change is expected to deteriorate health security by spreading vector-borne diseases. Effective governance and timely interventions can substantially shorten periods of food insecurity, lower their intensities, and accelerate recovery from inevitable crises, and are therefore crucial in preventing humanitarian crises. Since global drylands population will nearly double by 2050, and since drylands are among the most susceptible areas to climate change, integrated multi-hazard approaches to food security are needed.

A comparative, diachronic analysis of urban population dynamics allows for the identification of specific demographic trajectories influencing metropolitan expansion worldwide. However, a wide-ranging characterization of long-term population trends in metropolitan areas identifying sequential urban cycles with distinctive demographic dynamics is still incomplete. By hypothesizing a trade-off between ‘fast’ and ‘slow’ population dynamics that reflect ‘high’ and ‘low’ fertility regimes in both advanced and emerging economies, the present work investigates the relationship between city size (considering absolute population) and population growth rate in 1857 metropolitan agglomerations (>300,000 inhabitants in 2014) of 154 countries across the globe. Analysis covers a relatively long time period (1950–2030) and uses descriptive statistics (average and coefficient of variation) of the spatial series of population growth rates derived from United Nations demographics by metropolitan agglomeration and time interval. The results of our study indicate that metropolitan growth was associated with highly variable rates of population growth, being highly positive before 2000 and declining progressively in the subsequent decades. Despite important differences at the regional scale, an inverse relationship between population growth and city size was observed up to the late 1990s, with a higher spatial heterogeneity reflecting a moderate slowdown in demographic dynamics during recent years. Rapid population expansion dependent on city size and a higher spatial heterogeneity in growth rates insensitive to city size, evidence distinct metropolitan cycles reflecting worldwide transition from high to low fertility, ageing, and more unpredictable migration patterns.

Urban growth is a largely debated issue in social science. Specific forms of metropolitan expansion—including sprawl—involve multiple and fascinating research dimensions, making mixed (quali-quantitative) analysis of this phenomenon particularly complex and challenging at the same time. Urban sprawl has attracting the attention of multidisciplinary studies defining nature, dynamics, and consequences that dispersed low-density settlements are having on biophysical and socioeconomic contexts worldwide. The present commentary provides a brief overview on nature and implications of the latent relationship between sprawl, demographic dynamics, and background socio-environmental contexts with special focus on Europe. Empirical evidence supports the idea that spatial planning should cope more effectively with the increasing environmental and socioeconomic exposure of European regions to sprawl and demographic transitions, being progressively far away from a traditional urban cycle with sequential waves of urbanization, suburbanization, counter-urbanization, and re-urbanization. Growing socio-ecological vulnerability of metropolitan regions was evaluated based on a literature review demonstrating how a better comprehension of the intimate linkage between long-term demographic dynamics and urban cycles is necessary to inform fine-tuned policies controlling sprawl and promoting a sustainable management of peri-urban land.