Food demand displaced by global refugee migration influences water use in already water stressed countries

Ensuring the availability and sustainable management of water for all is a critical challenge. This is especially true when droughts coincide with rapid demographic change and ongoing armed conflicts. While water scarcity is rarely the sole cause of war, it can be a risk factor for civil conflicts and a link between climate change and violence. Armed conflicts also damage water infrastructure, disrupt water use, and displace populations, impacting water resources both locally and in neighboring countries. The recent Syrian civil war, for instance, caused a significant influx of refugees into Jordan, placing additional strain on Jordan's already limited water resources. This highlights how conflicts can affect water resources beyond political and geographical boundaries by displacing water demand through refugee migration. As of 2021, approximately 80 million people were forcibly displaced globally, with over 30 million migrating internationally as refugees. Between 2005 and 2016, the number of displaced refugees nearly doubled, a sharp increase. Many of these refugees originated from arid or semi-arid regions and migrated to neighboring countries often facing similar water challenges. Existing research focuses on the water security implications of migration in destination countries, identifying mechanisms such as overburdened infrastructure and disruptions to ecosystem services. However, a significant portion of a person's water consumption is embedded in food production. The concept of the water footprint quantifies this, measuring the volume of water needed to produce, process, and distribute a person's annual food consumption. This concept helps track countries' progress towards Sustainable Development Goals related to water stress, but it's crucial to understand that water stress is determined by water withdrawals within a country, which may differ from the water embedded in the food consumed by its population due to global food trade. Similar 'virtual' water flows can be associated with human movements, especially refugees. In contrast to economic migrants who often move to countries with higher water-intensive consumption, refugees mostly move to neighboring countries with comparable and often already stressed water resources, leading to increased water demands in their destinations. This study aims to characterize the amplitude of this effect and its repercussions on water stress.

The study contributes to two distinct bodies of literature. First, it adds to the research on the relationship between water resources and armed conflicts. While most research focuses on water scarcity as a driver of conflict, this study examines water as a consequence of conflict, demonstrating how the hydrological impacts of localized conflicts can become global due to food trade and human migration. Second, the study extends the concept of virtual water, initially applied to supply chains and the water footprint of displaced goods, to encompass the water demand of displaced people. By tracking the origin of water embedded in traded goods, the research clarifies both direct (migration) and indirect (trade) effects of refugee displacement on water stress. The utilized water footprint dataset uniquely distinguishes the effects of dietary habits, globalized supply chains, and agricultural water use efficiency. This allows for a more nuanced understanding of the complex interplay between refugee migration and water stress.

The researchers leveraged recent data on the water footprint of 370 food products to estimate the refugee-related increase in water demand in destination countries. They used UNHCR data on refugee displacement to create matrices representing the number of refugees from a country of origin living in a destination country each year. Data limitations necessitated adjustments in accounting for refugees from countries lacking complete water footprint data. The study period was 2005-2016, coinciding with the available virtual water dataset. The study incorporated both short-run and long-run water footprint estimations. Short-run estimates assumed refugees retain their original country's dietary habits but consume food from their destination country. Long-run estimates assumed refugees eventually adopt the dietary habits of their destination country. Both 'blue' (surface and groundwater) and 'green' (rainfall) water footprints were considered, with a focus on blue water due to its high opportunity cost. The data for water footprints came from the CWASI dataset, which combines trade data with a model of crop-specific water requirements. The study also accounted for the water embedded in food imports to better reflect the true water resource pressure. The methodology for calculating blue water footprints involved distinguishing between the direct (migration) and indirect (trade) effects of refugee displacement on water stress. Water stress was calculated using the UN SDG indicator 6.4.2, defining it as the ratio between total freshwater withdrawals and available water resources (total renewable water resources minus environmental flow requirements). The effect of refugee migration on water stress was determined by calculating the ratio of the blue water footprint of refugees in a country to the country's available water resources. This framework allowed researchers to quantify the contribution of refugee migration to existing water stress levels in various destination countries. Furthermore, the study examined the potential for alleviating water stress through refugee resettlement programs and increased food imports. The authors analyzed Pareto-optimal resettlement plans, balancing individual refugee hardship (approximated by waiting time for resettlement) and water stress relief in host countries.

The global water footprint of refugee displacement was estimated at nearly 31 km³ y⁻¹ in 2016, a 75% increase since 2005. This is significantly smaller than the water footprint of economic migrants and global food trade. However, the impact on water stress is disproportionately concentrated in a few countries. While refugees did not significantly contribute to overall water stress in most destination countries, the implications in some countries are substantial. Analysis revealed that the impact of refugee displacement on water stress varies considerably across different regions: * **High Impact Regions:** In countries like Jordan and Lebanon, already facing high water stress, refugee migration caused a dramatic increase in water stress (Jordan: 47–75 percentage points; Lebanon: 12.4 percentage points). In Jordan, while an increase in Yarmouk River flow due to abandoned Syrian agriculture partially offset the increased water demand, the net effect remains a substantial increase in water stress. * **Moderate Impact Regions:** In Iran, Pakistan, and Turkey, refugees had a noticeable but less severe impact on water stress, primarily due to the use of water resources in food production in these countries. * **Low Impact Regions:** In the European Union, the impact of refugee migration on water stress was negligible, largely because European food systems rely less on blue water for food production and import a substantial portion of food, reducing local stress. The study also analyzed the potential for water stress mitigation through refugee resettlement and increased food imports. Relocating refugees from water-stressed countries to water-abundant countries could alleviate water stress, but this comes with a tradeoff, as such resettlement might increase hardship for refugees. Small changes in resettlement plans, however, might yield significant water stress relief. Enhanced food imports from water-abundant countries could significantly reduce water stress in the short term, particularly in Jordan and Lebanon, but the effectiveness of this mitigation strategy is strongly non-linear and varies significantly between different types of food.

The findings highlight that while the global water footprint of refugee displacement is relatively small compared to other water uses, its impact is unevenly distributed and can be severe in already water-stressed countries. This uneven distribution underscores the need for targeted interventions. The study demonstrates that existing mechanisms, such as refugee resettlement programs and international food supply chains, offer potential for mitigating water stress related to refugee migration. The analysis shows that there's a tradeoff between alleviating individual refugee hardship and relieving water stress in host countries, indicating the need for policy decisions that balance both concerns. The considerable variation in the effectiveness of food imports in reducing water stress depending on the specific food type points to a need for targeted, strategic approaches in humanitarian aid and food security policies. The findings have implications for policy-making. While water stress shouldn't be the sole determinant of trade, aid, or migration policies, it's a critical factor to consider, especially in water-vulnerable regions. The study suggests that improving the water use efficiency of local food production and increasing food imports, potentially through food aid or trade agreements, are promising approaches to mitigate water crises in the short term. In the long term, safe repatriation or relocation of refugees to areas with more sustainable conditions remains an essential goal. This integrated approach acknowledging the complex interplay of humanitarian, economic, and environmental factors is necessary for effective and equitable solutions.

This study provides a quantitative assessment of the water footprint of global refugee displacement, revealing its disproportionate impact on water-stressed regions. While the overall global impact is relatively modest, the effect on specific countries can be significant, highlighting the need for targeted strategies. The findings underscore the potential of refugee resettlement and increased food imports as mitigation tools. Future research could focus on developing more detailed models that account for sub-national variations and incorporate other factors, including the impact of climate change and the evolving dynamics of conflict and migration. A deeper investigation into the tradeoffs between humanitarian goals and resource management is also critical.

The study acknowledges several limitations. Data availability constraints affected the analysis, particularly regarding refugees from countries with incomplete water footprint data and internally displaced persons (IDPs), who were excluded from the analysis due to a lack of sub-national data. The methodology relied on certain assumptions, such as the eventual adoption of destination country dietary habits by refugees (long-run analysis) and the consistent water intensity of food consumed by refugees compared to the local population. The study also excluded the gray water footprint and the direct water usage by refugees for domestic purposes. These limitations might affect the generalizability of the results and warrant caution when interpreting the findings.