The silent salinity crisis threatening global food security

When considering the effects of climate change, many people tend to think of headline-grabbing wildfires, superstorms, or mega-droughts. But some of the most devastating impacts are quiet and creeping. For example, ocean acidification, caused by absorption of anthropogenic carbon dioxide, is slowly reshaping marine ecosystems. Moving inland, a lesser-known insidious threat is also fundamentally altering the environment and very ground beneath our feet: rising salinity. 

But what exactly is getting saltier and what is driving it? In short, it is our soils, our groundwater aquifers, and our surface freshwater rivers. The reasons are complex and multi-factorial, but sea-level rise is playing a part in many coastal regions, pushing saltwater further into river deltas and estuaries. At the same time, soaring temperatures and increased evaporation leave concentrated salts behind in the earth. Human activities like the overexploitation of groundwater and the damming or draining of rivers mean less freshwater flowing downstream to push back the encroaching sea.

Crucially, it is a direct threat to the global food supply. When soil becomes too saline, it essentially dehydrates plants. Even if the ground is wet, high salt concentrations make it incredibly difficult for crop roots to absorb essential water and nutrients – stunting plant growth and drastically reducing harvest yields. Eventually, rising salinity can render the land impossible to farm, disrupting the entire intricate water, energy, food, and ecosystem (WEFE) nexus.

Recently, researchers and policy experts came together to discuss these issues at a WEFE Nexus Policy Webinar (the eighth in an ongoing series), focusing on how to adapt agriculture and water management to this escalating crisis. The insights highlight a pressing need to bridge global predictive modeling with local, community-driven transitions.

Mapping global vulnerability

To understand where the danger is most acute, we must look beyond isolated data points. By combining soil and water salinity data with eight critical variables – including precipitation, evaporation, groundwater depth, and irrigation practices – it is possible to identify global vulnerability hotspots (Islam et al., 2026; in press).

Concerningly, regions traditionally vital for global grain production, such as Southeast Asia, South Asia, and parts of North America, show high vulnerability. Added to that, crops with lower salt tolerance like maize and rice are currently being cultivated in these highly vulnerable zones at much higher rates than more salt-tolerant crops like wheat. If salinity continues to increase in these vital agricultural hubs, the cascading impact on global food security will be severe.

To see how these global models translate to local realities, Bangladesh serves as a critical case study. As one of the world’s largest deltas, the nation relies on a vast network of rivers flowing down from the Himalayas to push back the sea and sustain its fertile plains. While the nation’s Delta Plan 2100 projected future water salinity, future soil salinity remained a difficult unknown. To bridge this gap, researchers are now turning to cutting-edge technology. By applying machine learning and data-driven models to environmental parameters, projections for the future show a creeping “red zone” of high salinity moving further inland into the country’s south-central regions. This is worrying because these areas are reliant on freshwater reserves and produce a significant amount of rice and grain. The analysis also illustrates how climate stressors vary even within a single country: while the northwest of Bangladesh battles drought and riverine flooding, the southwest is fighting prolonged coastal flooding and an encroaching wall of salinity.

The reality on the ground

Predictive models are only half the equation. The other half is understanding the human element on the ground. A recent program, Deltas Under Pressure, convened workshops with farmers across low, medium, and high salinity zones in coastal Bangladesh, revealing a complex picture of adaptation. Where salinity is already high, farmers are actively moving to adapt through short-term agronomic solutions like using drip irrigation, planting salt-tolerant crop varieties, and applying a mulch covering which slows evaporation and prevents deep salts being pulled up.

However, adaptation is not always about choosing the most resilient plant. Driven by immediate economic survival, some farmers are actually transitioning away from salt-tolerant crops like sesame to less tolerant but higher-value crops like early-season watermelon simply to fetch a higher market price. Others are shifting their entire livelihood away from traditional crops and into saline aquaculture to farm shrimp and crabs. While this offers lucrative short-term economic gains, it deliberately brings salinity into the environment, degrading nearby soil and groundwater and making it incredibly difficult to reclaim the land for traditional agriculture if the aquaculture fails.

Conversely, in currently low-salinity areas, farmers are largely unaware of the impending impacts and are not yet changing their farming strategies. This highlights a critical, missed opportunity for proactive adaptation and knowledge sharing.

From field to regional scale

Addressing the salinity crisis requires acknowledging the limits of individual action. A single farmer can adopt short-term, field-level solutions like mulching or planting saline-tolerant varieties. However, true long-term resilience requires water management solutions at the regional level, where an integrated systems approach becomes vital. For example, in Bangladesh polders are enclosures protected by raised earthen embankments to defend against coastal flooding and protect crops and fisheries. A systems approach means designing and operating shared infrastructure, like regional sluice gates, to balance the competing freshwater needs of farmers with the brackish water needs of aquaculture.

Transforming water management at this scale requires agricultural and water ministries to break down silos and work together. In Bangladesh, researchers and government officials are currently developing a collaborative framework for water management. This aims to create clear institutional arrangements and empower local water user organizations to coordinate competing claims, resolve conflicts, and sustain the infrastructure over the long term.

The threat of rising salinity is a present reality reshaping deltas and agricultural heartlands around the world. By combining forward-looking predictive data with deeply integrated, regional water management strategies, we can begin to chart sustainable pathways to secure the food systems of tomorrow. 

Feroz Islam is a Researcher in Water & Food at Wageningen University & Research; Catharien Terwisscha van Scheltinga is a Senior Researcher at Wageningen University & Research, and a Senior Expert affiliated with the International Water Management Institute (IWMI) through the Netherlands – CGIAR Partnership Programme; Alok Sikka is an Emeritus Scientist at IWMI; and Mohsin Hafeez is Strategic Program Director for Water, Food and Ecosystems, IWMI. 

This work was carried out under the CGIAR Initiative on NEXUS Gains and finalized with support from the CGIAR Policy Innovations Program. We would like to thank all funders who supported this research through their contributions to the CGIAR Trust Fund (www.cgiar.org/funders).

For more information contact: [email protected]