Around 16 percent of all agricultural land worldwide is artificially irrigated and heavily fertilized. When this water evaporates, salts accumulate in the upper soil layers. As a result, the soil is in danger of becoming salinized and infertile. With the increase in extreme weather events such as summer heat and heavy rain, this process is being exacerbated even further. Combining a comprehensive series of climatic, soil and remote sensing data and machine learning algorithms, Professor Nima Shokri of the Institute of Geo-Hydroinformatics at Hamburg University of Technology has succeeded to provide the first prediction of the future of soil salinization at the global scale up to the year 2100 under different climate scenarios. His results have now been published in the renowned journal Nature Communications.
Global scale analyses of soil salinization
To predict future soil salinity, Shokri used more than 40,000 measured values of soil salinity across the globe. Additionally, they identified several climatic and soil related parameters such precipitation, evaporation and soil type that influence soil salinity. On this basis, the TU scientist trained models with machine learning algorithms to find a relationship between salinity and these parameters. These trained models were used to predict soil salinity on a global scale up to the year 2100 under different climate change scenarios. "Using Big Data analyses and machine learning algorithms, we were able to determine the salinity of the soil globally with a high spatial and temporal resolution," the scientist says. According to Shokri's research, changes might be inevitable by the year 2100 if we do not take the necessary actions: "Without sustainable resource management and with the business-as-usual-attitude toward climate change, further soil salinization and degradation and possible 'tipping point' where the system collapses would be inevitable".
Apple orchards in the Alte Land also at risk
Soil salinization could also become a problem for Germany, although for very different reasons than in arid zones. Rising sea levels affect coastal regions. If saline seawater penetrates and reaches groundwater in the future, it could contaminate it. For Hamburg and the surrounding area, perhaps the apple orchards in the Alte Land would be in danger if farmers then irrigate their trees with salty water.
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