How salinity could become the most important environmental parameter

While environmental monitoring professionals are keeping track of aerosols, greenhouse gases, nutrients, PFAS and microplastics, salinity is rapidly becoming a central concern for businesses and governments. Jed Thomas  

Salinity monitoring, once considered a niche concern for marine scientists and agriculturalists, has emerged as a critical parameter for a wide range of environmental, economic, and public health challenges in the 21st century.  

From coastal ecosystems and freshwater supplies to agricultural productivity and climate change resilience, salinity data now underpin decision-making across disciplines.  

For monitoring professionals, understanding the far-reaching significance of salinity is essential for navigating the complex environmental realities of our time. 

The expanding scope of salinity monitoring 

Salinity refers to the concentration of dissolved salts in water or soil. While natural salinity levels vary across environments, anthropogenic influences such as irrigation, industrial discharges, and climate change have dramatically altered salinity patterns.  

In coastal areas, rising sea levels and increased storm surges lead to saltwater intrusion into freshwater aquifers and agricultural lands, compromising drinking water supplies and food security.  

Inland, excessive irrigation without proper drainage causes soil salinization, reducing crop yields and rendering land infertile. 

According to a 2024 report by the UN Food and Agriculture Organization (FAO), soil salinity now affects approximately 1.4 billion hectares globally, with the potential to reduce crop yields by up to 70%.¹ 

Moreover, salinity has direct implications for infrastructure. Elevated salt levels in water corrode pipelines, treatment facilities, and storage systems, increasing maintenance costs and reducing the lifespan of public and private assets.² 

Studies on freshwater salinization have shown that increased salinity levels can lead to infrastructure degradation and significant biodiversity loss, emphasizing the need for effective salinity monitoring. 

In estuarine and marine environments, salinity shifts disrupt aquatic ecosystems, altering species distributions and threatening biodiversity. 

Why salinity monitoring is climate monitoring 

Salinity monitoring is a powerful tool for assessing climate change impacts and building resilience.  

Shifts in rainfall patterns, drought frequency, and sea-level rise all influence salinity levels in soils and water bodies.  

By tracking these changes, monitoring professionals can anticipate emerging risks and support adaptive management strategies.  

For instance, early detection of saltwater intrusion can guide the implementation of protective barriers or alternative water sourcing, while soil salinity data can inform sustainable land-use practices. 

Research published in the journal Remote Sensing highlights the role of long-term salinity monitoring in understanding the impacts of climate change.³ 

Over a 30-year period, this research tracked salinity dynamics, revealing significant changes tied to climate variables and underscoring the value of salinity data in climate adaptation efforts. 

In agricultural regions, salinity monitoring enables precision farming. By tailoring irrigation practices and crop choices to real-time salinity data, farmers can maintain productivity while conserving water and minimizing environmental harm.  

This is especially important in arid and semi-arid regions, where the margin for error is slim and the consequences of mismanagement are severe. 

Does increasing freshwater salinity breach planetary boundaries? 

The concept of planetary boundaries defines the safe operating space for humanity with respect to critical Earth system processes.⁴  

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While salinity is not explicitly listed as a separate boundary, it is intrinsically connected to several of them.  

Elevated salinity levels compromise the freshwater use boundary by rendering freshwater resources unusable for drinking, agriculture, and ecosystems.  

Salinization also affects biosphere integrity, as shifts in salinity can cause biodiversity loss, particularly in sensitive estuarine and coastal ecosystems.  

Additionally, salinity is indirectly linked to biogeochemical flows (nitrogen and phosphorus cycles), as fertilizer use and irrigation practices influence salinity in soils and water bodies.  

These connections reinforce the global significance of salinity monitoring, emphasizing its role in maintaining Earth system stability and human well-being. 

We need new salinity monitors and protocols 

Technological advances have made salinity monitoring more accessible than ever. Low-cost sensors, remote sensing technologies, and integrated data platforms enable continuous, real-time monitoring at various scales.  

These tools empower communities, governments, and industries to make data-driven decisions that protect resources and livelihoods.  

Importantly, open data initiatives and citizen science projects are expanding the reach and impact of salinity monitoring, fostering a collaborative approach to environmental stewardship. 

In an era defined by environmental uncertainty, salinity monitoring is not merely a technical task; it is a cornerstone of sustainability and resilience.  

For monitoring professionals, the ability to measure and interpret salinity data is increasingly vital, influencing water management, food production, public health, and ecosystem conservation.  

As salinity challenges grow in scope and severity, so too does the importance of proactive, informed monitoring.  

By prioritizing salinity as a key parameter, we can better navigate the interconnected challenges of the 21st century and safeguard our shared future. 

¹ Global status of salt-affected soils. Alloush et al. Food and Agriculture Organization of the United Nations. 2024.

² Freshwater salinization syndrome on a continental scale. Kaushal et al. Proceedings of the National Academy of Sciences. 2018.

3 Assessing climate change impact on soil salinity dynamics between 1987–2017 in arid landscape using landsat TM, ETM+ and OLI data. Abderrazak Bannari and Zahra M. Al-Ali. Remote Sensing. 2020.

4 A safe operating space for humanity. Rockström et al. Nature. 2009.