Scenario-based Analysis of the Impacts of Lake Drying on Sustainable Food Production

In many parts of the world, lake drying is caused by water management failures, while the phenomenon is exacerbated by climate change. Lake Urmia in Northern Iran is drying up at such an alarming rate that it is considered to be a dying lake, which has dire consequences for the whole region. While salinization caused by a dying lake is well understood and known to influence the local and regional food production, other potential impacts are as yet unknown. Food production in the Urmia region has predominantly been regionally-oriented and sustainable, particularly in terms of water demand. To explore current and projected impacts of the dying lake on sustainable food production (SFP) we investigated changes in climatic conditions, land use, and land degradation for the period 1990-2020. We examined the environmental impacts of lake drought on SFP through an integrated scenario-based geoinformation framework. The results show that the lake drought has significantly affected food production and has reduced the proportion of SFP over the past three decades. Based on a combination of cellular automata and Markov modelling, the conditions are projected for the next 30 years and are predicted to exacerbate further. To mitigate these issues and support SFP, this research provides some policy recommendations and results for tangible action plans. We consider the modification of cropping patterns towards low water demand crops as one the cheapest and most efficient solutions for reducing the overall agricultural water consumption.

Global drying of major saline lakes

<p>Water resources are deteriorating across the world, which is of particular concern in water-scarce arid and semi-arid regions. Saline lakes often lack outflow, and are vulnerable to environmental change. When they start to shrink, salinity levels increase, due to evapoconcentration of salts in the reduced water volumes. This may harm the aquatic environment and limit the usability for humans. The associated exposure of their dry lakebeds may also bring severe regional problems of wind-blown saline dust and soil degradation. Although some of the world’s major cases of lake drying have been well studied, like the case of the Aral Sea desiccation, there is a lack of coherent assessments made at the global scale. Such assessments are critical for identifying vulnerable regions and main drivers of change, which may contribute to the prevention of future catastrophes. We here synthesise information on and analyse the desiccation status of 28 major saline lakes, each one of them having a surface area of ≥ 100 km<sup>2</sup> and salinity of ≥ 10 g·L<sup>-1</sup>. They are geographically distributed over the world’s all continents, except Europe and Antarctica. In total, our results show that more than half of the world’s major saline lakes have dried up considerably in the last couple of decades. Out of these, 36 % are already, or are close to being completely desiccated. Preliminary analyses show correlations between original lake depth, lake bathymetry and resulting lakebed exposure from drying, suggesting that a lake’s general resilience to drying may be predictable. Our estimates further show that the world’s major saline lakes together contain 1177 billion tonnes of salt, of which 79 billion tonnes are currently in drying or already dried up lakes. If all of these lakes would desiccate, around 1 billion people are currently living within reach of saline dust storms that could spread from dry lakebeds.</p>