Despite being a topical issue in public debate and on the political agenda for many countries, a global-scale, high-resolution quantification of migration and its major drivers for the recent decades remained missing. We created a global dataset of annual net migration between 2000 and 2019 (~10 km grid, covering the areas of 216 countries or sovereign states), based on reported and downscaled subnational birth (2,555 administrative units) and death (2,067 administrative units) rates. We show that, globally, around 50% of the world’s urban population lived in areas where migration accelerated urban population growth, while a third of the global population lived in provinces where rural areas experienced positive net migration. Finally, we show that, globally, socioeconomic factors are more strongly associated with migration patterns than climatic factors. While our method is dependent on census data, incurring notable uncertainties in regions where census data coverage or quality is low, we were able to capture migration patterns not only between but also within countries, as well as by socioeconomic and geophysical zonings. Our results highlight the importance of subnational analysis of migration—a necessity for policy design, international cooperation and shared responsibility for managing internal and international migration.

Informal settlements i.e., slums emerge from the interplay of multidimensional factors related to urbanization and sustainability. While the contribution of urban factors is well understood, the role of external drivers, such as uncontrolled migration to urban areas, is rarely addressed in research or policy-making. This study develops a novel conceptualization of slums by reviewing the pushing and pulling factors of migration and their contribution to informal settlements through 1) a socio-ecological system approach and 2) the concept of adaptive capacity. Further, it advances the discussion around synergistic and coherent policy-making in the urban context by reviewing three urban agendas and further using water as a case with the concept of cross-cutting domains. We show that the emergence of urban challenges can, and should be, linked to the root causes of flows into urban areas. Understanding these linkages through a socio-ecological system framework opens a window for knowledge-based policy development and addressing the question of how to avoid unsustainable urban development. Urbanization is one of the phenomena where the excessive complexity and dimensions of problems should not hamper action but instead, actions should be encouraged and enabled with synergistic and integrative pathways for sustainable urban development.

China’s rapid urbanization in areas prone to flood or drought events can be seen as a double-edged sword. Urbanization enlarges the population exposed to these hazards, but the resulting socio-economic development also helps build resilience. This article quantifies flood occurrence, drought severity, and related resilience in 81 cities in Mainland China. The extent of flood exposure was notable, both in absolute terms as well as in relation to the drought-prone urban population. China needs to integrate urban flood/drought policy making with sustainable urbanization policy making to best contribute to minimizing flood and drought risks in its cities.

Income inequality is one of the most important measures to indicate economic health, social justice, and quality of life. Yet, especially at the subnational level, comprehensive global data on the distribution of incomes is widely missing. Such data is essential to assess patterns in inequality within countries and their development over time. We created seamless global subnational Gini coefficient and gross national income (GNI) PPP per capita datasets for 1990-2021 and used these to assess the status and trends of income inequality and income as well as their interplay. We show that while gross national income has increased for most (96%) people globally, inequality has also increased for around 68% of the global population. We illustrate heterogeneities in inequality trends between and within countries and analyse plausible confounding factors related to inequality. Our dataset and analyses reveal new insights into the issue, opening novel research avenues at the global, regional or national level and providing comprehensive evidence for policymakers to make informed decisions.