On 4 November 2022, the RIAS hosted a policy workshop titled “Soil Salinization: Global Problem, Local Solutions.” The workshop aimed to address the global issue of soil salinization by fostering collaboration, sharing innovative solutions, and promoting sustainable governance of coastal regions susceptible to salt accumulation, particularly in the Netherlands and the United States.
Soil salinization, the process of salt accumulation in terrestrial landscapes, is arguably one of the least known effects of climate change but one of the most impactful. Although a natural phenomenon, human activities have significantly contributed to its acceleration and intensification in recent years, making it a pressing threat to human activities and ecosystems.
Arid and semi-arid regions are typically associated with the potential for salinization. However, a dry climate is just one of many risk indicators. Rising sea levels and rampant coastal erosion, characteristic of the current climate emergency, are significant drivers of salt accumulation in previously unaffected territories. Simultaneously, poor agricultural and water management practices, such as improper drainage, irrigation with salt-rich waters, and inappropriate use of fertilizers, can seriously damage the delicate saline balance of soil and water.
Delta regions, which are among the most environmentally rich and diverse areas globally and some of the most highly stressed and exploited spaces on Earth, are particularly exposed to salinization and its disruptive consequences. Their natural characteristics make them prone to flooding, subsidence, and direct saltwater intrusion – occurrences that can lead to the accumulation of water-soluble salts such as sodium, calcium, chloride, sulfate, and bicarbonate in soil and water. Furthermore, due to intense competition for land and water use in these areas, the adverse effects of salinization are heightened in coastal zones and wetlands.
Salt accumulation poses a significant physiological threat to ecosystems and can result in potentially devastating outcomes in vulnerable areas. High salt concentrations destroy crop production, as salt influences plant development and affects soil organisms’ metabolism, leading to severely reduced soil fertility. Even when salinization does not turn previously arable land into a wasteland, it forces farmers to abandon traditional cultivation methods and, when possible, switch to more salt-tolerant crops. This process reduces food variety for human consumption, erodes biodiversity, and jeopardizes agricultural activities, including livestock production. Furthermore, the deterioration of water quality severely impacts industrial practices reliant on constant freshwater inflow; it also threatens drinking water supplies and increases water management and treatment costs for local populations.
In October 2021, as a testament to the global extent of the danger, the UN Food and Agriculture Organization co-organized a Global Symposium on Salt-Affected Soils (GSAS21) that focused on “halting soil salinization and boosting soil productivity.” The increasing awareness of the effects of salt concentration and interest in finding shared solutions have prompted experts worldwide to work on innovative methods and technologies that could help tackle the problem. Specific initiatives to bring relief to different territories impacted by salinization have also multiplied at the national level. In the United States, for example, the Fish and Wildlife Service awarded over $20 million in December 2021 to support projects in 13 coastal states. These projects aimed to protect and enhance thousands of acres of coastal wetlands endangered by salt intrusion, rising sea levels, and increasing human activities. With its coastal regions surrounded by oceans and reliant on productivity, salinization is an especially problematic issue in the United States. However, the problem of salinization is also significant in areas like Zeeland, where an extensive agro-industrial complex thrives near the salty waters of the North Sea and on a territory mostly below sea level.
Addressing the complexity of the issues at stake requires combining scientific and technological knowledge with long-term, forward-looking policy planning. Local authorities must also be involved, addressing salt concentration as a serious public policy issue and proposing a vision for reorganizing and adapting industrial and agricultural spaces and coastal landscapes. To help bridge the gap between technical expertise and policymaking and facilitate knowledge transfer across the Atlantic, the RIAS organized an international workshop on soil salinization in November 2022. The workshop, which aimed to address a global problem through local solutions and adaptations, laid the foundation for a policy-oriented discussion that identified best practices for the sustainable governance of coastal regions susceptible to salinization.
One of the speakers in Middelburg, Molly Mitchell, Program Director and Research Assistant Professor at the Center for Coastal Resources Management of the Virginia Institute of Marine Science, highlighted the importance of studying adaptive technologies to reduce salt accumulation in estuarine and coastal areas. Her work focuses on the delicate landscape of Chesapeake Bay, the United States’ largest estuary, with over 150 major rivers and streams flowing into it. Her concerns about the transformation of upstream creeks, whose salinity is increasing, reflect a growing problem shared between the two sides of the Atlantic. Indeed, these smaller ditches and canals, once crucial for agricultural and irrigation purposes, are now turning into areas where salt accumulates rapidly, foreshadowing the progressive deterioration of the surrounding ecosystem. Without appropriate countermeasures, the salinity of entire drainage basins, watersheds, and river systems in affected areas can rise to dangerous levels for life and habitat.
To address such environmental pressures, public and private actors must invest in innovative solutions. A promising example of a technological fix is the “Sustainable Water Initiative for Tomorrow” (SWIFT), developed by the Hampton Roads Sanitation District. SWIFT is a water treatment project in eastern Virginia designed to enhance the region’s long-term groundwater supply sustainability and help address environmental pressures. In practice, it involves taking highly treated water that would otherwise be discharged into the Elizabeth, James, or York rivers, subjecting it to additional rounds of advanced water treatment to meet drinking water quality standards, and injecting it back into the Potomac Aquifer, eastern Virginia’s primary groundwater source. Through this method, SWIFT can provide a sustainable resource to replenish groundwater in several coastal communities while reducing salt levels in the soil and nitrogen accumulation.
The search for technological remedies and opportunities is one of the many paths connecting experts across the Atlantic. Research and development in soil-resistant crops have attracted wide attention in both the Netherlands and the United States. For example, Christopher Miller, an agronomist working at the Cape May Plant Materials Center of the US Department of Agriculture, has shared the results of multi-year research on native plants and bushes capable of collecting and retaining salt accumulated in the soil. The outcomes have been highly positive, thanks to the selection and use of plants commonly found in coastal dunes and shorelines. USDA experts identified those species that guarantee the best efficiency and effectively restored salt-affected soils by creating buffer zones in adjacent canals. In doing so, they have revitalized the natural landscape while considering farmers’ needs.
The USDA has consistently oriented its research to develop valuable strategies for farmers whose land productivity has been severely reduced by changes in climatic and non-climatic factors and ecological conditions. This approach has led to the adoption of different kinds of crops and, consequently, additional agricultural output, including oilseed and biodiesel production. Dr. Miller presented these positive interactions as the outcomes of fruitful “coastal ecotone interactions,” which have represented a successful example of resilient solutions and adaptations that could potentially be replicated on a broader scale.
On the European side, Dutch experts like Marcela Laguzzi, Senior Program Manager of Fresh Waters at the Ministry of Infrastructure and Water Management, confirmed the Dutch government’s role at the forefront of efforts to preserve freshwater resources. The Hague leads and coordinates the Netherlands International Water Ambition (NIWA), a multilateral program that assists countries facing water-related challenges in addressing complex and urgent issues like salinization.
In 2022, the Dutch government also greenlit an additional 800 million euro investment package to advance the Freshwater Delta Plan to its second stage, during which it will become possible to implement several measures to control not only soil salinization but also nitrogen deposition and carbon emissions. Furthermore, a crucial aspect of the Dutch Ministry of Infrastructure and Water Management’s strategy revolves around sharing technical know-how and general information, particularly among communities and groups of citizens most affected by these phenomena. For instance, empowering farmers and increasing their awareness about the challenges of salt intrusion has been one of the main pillars upon which Dutch policymakers have built their national and regional anti-salinization policies.
At the local level, this has meant establishing projects like the Schouwen-Duiveland Living Lab, a private-public partnership actively seeking innovative solutions for complex water-related issues, stimulating education, and promoting good governance in the southwestern part of the Netherlands. Similarly, the Province of Zeeland has coordinated a groundbreaking salt intrusion monitoring and mapping project. As explained by Vincent Klap, Senior Policy Water Officer of the Province of Zeeland, since 2016, water managers in Zeeland have been able to measure and identify, through aerial scanning, the most critical points of salt intrusion. This effort has enabled Zeeland authorities to precisely locate the most concerning ditches and salt creeks and potentially plan targeted remedial actions. In this respect, the goal for both the national government and local actors is to transform Zeeland into one of the world’s first climate-resilient regions by 2050.
The breadth of the problem and the many ways it affects different ecologies worldwide make the challenge even more complex. The HZ University of Applied Sciences in Vlissingen is involved in projects in over 280 localities worldwide, conducting research and coordinating work on coastal and delta issues, including soil salinization. While the ecological problems these areas face are similar, finding a catch-all solution is challenging due to the unique characteristics of each place and the different needs of the communities living there, as confirmed by Liliane Geerling, HZ’s Senior Lecturer and Researcher. Determining adaptive strategies that consider local socio-ecological conditions and priorities remains the main difficulty for scientists and policymakers. Only continuous investment in research and knowledge sharing can guarantee the identification of best practices and the implementation of practical solutions on both sides of the Atlantic.
To view the complete program of the event and the full list of speakers, please click here.