Over 10% of global land affected by salinity: FAO report

The Food and Agriculture Organization of the United Nations (FAO) has released its first major global assessment of salt-affected soils in 50 years. The report reveals that nearly 1.4 billion hectares of land (just over 10 percent of the total global land area) are already impacted by salinity, with an additional one billion hectares at risk due to the climate crisis and human mismanagement.

The Global Status of Salt-Affected Soils report was presented during the International Soil and Water Forum 2024 in Bangkok. The event, co-organized by FAO and Thailand’s Ministry of Agriculture and Cooperatives, focused on developing an action plan to halt and reverse soil degradation and water scarcity.

Excessive salinity reduces the fertility of soils and severely impacts environmental sustainability. In the countries most affected by this issue, salinity stress can lead to crop yield losses – such as rice or beans – of up to 70 percent. This comes at a time when there is an urgent need to boost food production to feed a growing global population.

The report estimates the area of salt-affected soils at 1381 million ha (Mha), or 10.7 percent of the total global land area. It further estimates that 10 percent of irrigated cropland and 10 percent of rainfed cropland are affected by salinity, although uncertainty remains high due to limited data availability.

Models of global aridity trends indicate that, under the existing trend of temperature increase, the affected area may increase to between 24 and 32 percent of the total land surface. The vast majority of aridification is expected to occur in developing countries.

Today, 10 countries (Afghanistan, Australia, Argentina, China, Kazakhstan, the Russian Federation, the United States, Iran, Sudan, and Uzbekistan) account for 70 percent of the world's salt-affected soils.

The Drivers of Salinization
The climate crisis is increasing aridity and freshwater scarcity. Rising sea levels are projected to place more than one billion people in coastal zones at risk of progressive flooding and salinization by the end of the century. Additionally, global warming is contributing to salinization through the thawing of permafrost.

Inadequate agricultural practices also play a significant role. These include irrigating crops with poor-quality water, inadequate drainage, deforestation, the removal of deep-rooted vegetation, excessive water pumping in coastal and inland areas, overuse of fertilizers, de-icing agents, and mining activity.

Global freshwater use, in particular, has increased sixfold over the last century, contributing to groundwater salinization through the overexploitation of aquifers for irrigation purposes.

Need for Action
The report offers several strategies for managing salt-affected soils sustainably. Mitigation strategies include mulching, using interlayers of loose material, installing drainage systems, and improving crop rotations. Adaptation strategies include breeding salt-tolerant plants (such as halophytes, which thrive in mangrove swamps, tropical sand and cliff shorelines, and even salt deserts) and bioremediation—using bacteria, fungi, plants, or animals to remove, destroy, or sequester hazardous substances from the environment.

The report also calls for a legal framework at the national and international levels to safeguard natural saline ecosystems and ensure the sustainable management of agricultural soils under irrigation, particularly in areas at risk of salinization.