Inequalities in future hotspots of coastal water pollution and their socioeconomic drivers in Africa and Asia: a multi-pollutant modelling approach

Future coastal water quality is expected to be at risk due to growing socioeconomic developments including economy, population, urbanization, and agriculture. While challenges to water quantity are widely acknowledged and water quality studies for single pollution types are available, inequality aspects are hardly addressed between coastal water pollution and socioeconomic drivers worldwide in a spatially explicit way. Economic inequalities play a key role in shaping the impacts of coastal water pollution, making low-income communities more vulnerable to its effects on health and livelihoods while limiting their ability to respond to pollution reduction. Research on economic inequalities in coastal water pollution has predominantly focused on single pollutants at regional levels, particularly in the Global North (e.g., the United States and Europe). In contrast, the Global South (e.g., Africa and Asia), which is expected to face severe multi-pollution challenges, has been, less studied. Moreover, most studies rely on empirical approaches and do not often incorporate socioeconomic distributions into pollution modelling frameworks. Furthermore, comprehensive global models that address multiple pollutants, their sources, and the distribution of pollution hotspots across different income groups remain scarce.

This study models the distribution of future multi-pollutant hotspots for coastal waters and analyses them in relation to income classes and future socioeconomic developments. Using the MARINA-Multi model¹ (developed in previous studies), we project river exports of nutrients, plastics and chemicals under an economic-driven scenario with reactive environmental management, and we identify coastal water pollution hotspots and their drivers, and analyze them concerning income levels. Our preliminary results reveal pronounced regional and income-based disparities in future pollution hotspots, with stark contrasts between Africa and Asia. By 2050, Asia is projected to face severe pollution driven by rising fertilizer use, related to agricultural intensification, and plastic waste despite ongoing efforts to reduce fertilizer and manure use. In contrast, Africa’s pollution challenges will primarily originate from rapid population growth and inadequate sanitation systems, reflecting a lack of advancement in wastewater and solid waste management services that cannot keep pace with its fast-growing population. These differing drivers highlight the distinct socio-economic and infrastructural challenges faced by each region. By linking socio-economic factors to pollution, this research supports strategies for improving water quality and advancing Sustainable Development Goals 6 and 14, offering critical insights for better global water resource management.

References

¹ Micella, I., Kroeze, C., Bak, M. P., Tang, T., Wada, Y., & Strokal, M. (2024). Future scenarios for river exports of multiple pollutants by sources and sub-basins worldwide: Rising pollution for the Indian Ocean. Earth's Future, 12, e2024EF004712. https://doi.org/10.1029/2024EF004712