Conflict-driven farmland abandonment in Syria leads to land uplift, study finds

Conflict-driven farmland abandonment in Syria leads to land uplift, study finds

The Syrian civil war, which commenced in 2011, has resulted in extensive population displacement and significant damage to infrastructure. However, it has also produced an unforeseen environmental consequence, resulting in impactful alterations to the nation's landscape, as detailed in a recent study published in Geophysical Research Letters. This research emphasizes the multifaceted effects of conflict on water resources, which can manifest directly through wastewater contamination and the destruction of water infrastructure, or indirectly through heightened deforestation, soil erosion, and rapid losses of cropland.

Saeed Mhanna, from the University of Neuchâtel, Switzerland, along with his colleagues, reveals that the widespread abandonment of farmland in Syria, combined with the abrupt cessation of irrigation, has allowed underground aquifers to replenish. This replenishment has subsequently caused an uplift of the land above these aquifers at rates reaching up to 4 centimeters annually. These findings underscore how human activity—or its sudden cessation—can induce significant shifts in the Earth's surface in a region long afflicted by groundwater overexploitation.

Reshaping the landscape

Prior to the conflict, the agricultural practices in northwest Syria heavily depended on groundwater resources. Decades of intensive irrigation led to severe depressions in aquifers, the drying up of perennial springs, and diminished river flows. The ongoing conflict has forced many farmers to abandon their lands, leaving extensive areas of previously irrigated fields unmaintained. With the cessation of irrigation and the absence of water extraction for crops, subterranean reservoirs have begun to refill.

Utilizing satellite radar data, researchers were able to monitor minute movements of the land surface over time. Gathering environmental data in conflict zones presents notable challenges, as the scarcity of ground measurements often leads to significant knowledge gaps. Remote sensing, however, offers an unobstructed perspective from space. By integrating Interferometric Synthetic Aperture Radar (InSAR) data with vegetation and precipitation information, the scientific team was able to discern changes in land surface that were primarily driven by groundwater recovery, as opposed to seasonal growth patterns or rainfall alone.

Consequently, vegetation served as an essential indicator of irrigation activity. The researchers employed the satellite-derived Normalized Difference Vegetation Index (NDVI) to assess plant vitality. Areas that exhibited a marked decline in summer NDVI, indicative of abandoned cropland, showed a robust correlation with upward land movement. Conversely, regions maintaining steady irrigation, marked by stable vegetation, continued to face land subsidence.

Croplands situated on older Neogene rocks (dating from 2.6 to 23 million years ago), which overlay soluble limestone aquifers capable of rapid water flow, demonstrated the most pronounced land uplift. In contrast, younger Quaternary soils (less than 2.6 million years old), composed of clay-heavy layers that hamper water movement, displayed slower recovery rates, particularly in sectors that remained subject to irrigation and thus continued to subside.

Additionally, there was an increase in river flows, and some previously dry springs reappeared. Conversely, areas that continued to extract water through pumping exhibited ongoing subsidence, thereby demonstrating a clear connection between human water usage and alterations to the physical landscape.

Implications for future water management

Groundwater represents a vital resource in Syria's semi-arid climate, and this study highlights the associated risks and opportunities inherent in its management. While the ongoing conflict has inadvertently facilitated the recovery of aquifers, an important cautionary note is warranted: should irrigation resume at a significant scale, the potential for over-extraction could quickly re-emerge, possibly reversing the beneficial changes observed during the period of abandonment.

This study also exemplifies the utility of remote sensing in bridging critical data gaps in resource-poor regions. By scrutinizing satellite radar, vegetation indices, and precipitation trends, scientists can monitor groundwater dynamics effectively without reliance on traditional field measurements, which are essential in areas hindered by political instability or conflict that precludes ground-based observation. Therefore, this research establishes a valuable precedent for employing technology in the monitoring and management of water resources within regions vulnerable to both anthropogenic and climatic stresses.

Written for you by our author Hannah Bird, edited by Gaby Clark, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you.