The Temporal Change of Factors Affecting Water Stress: MARS Method

This study focuses on 40 countries experiencing very high and high water stress in 2016 and 2021 and examines the effects of ecological areas, forest areas, water efficiency, carbon dioxide emissions, and economic growth on water stress using the Multivariate Adaptive Regression Splines (MARS) method. The findings show that the impact of environmental factors on water stress changes over time, and that economic growth reduces water stress when evaluated together with ecological areas and forest areas; however, the effects of carbon dioxide emissions and water efficiency differ across years. The study indicates that in order to ensure sustainability, these environmental factors should be protected and the efficient use of these resources should be increased within the scope of water management and environmental policies. In addition, it emphasizes that policies aimed at reducing carbon dioxide emissions should be implemented in order to maintain sustainable economic growth. When the relative importance levels of the variables are examined, forest areas, carbon dioxide emissions, and ecological areas, which had relatively lower importance compared to other variables in 2016, increase in importance in 2021, indicating that all variables have high importance for water stress and that all factors examined in the study should be considered in policy development processes aimed at reducing water stress. The study focuses on the Sustainable Development Goals (SDGs), particularly Goal 6: Clean Water and Sanitation and Goal 15: Life on Land. Especially within the scope of Goal 15, it is emphasized that green terrestrial areas should be protected and that achieving Goal 6 becomes easier when Goal 15 is fulfilled. This is because terrestrial ecosystems regulate the water cycle, ensure the natural flow of water, and contribute to the recharge of groundwater resources, thereby supporting the sustainability of water resources. These findings also demonstrate that the MARS approach can be used in environmental sustainability analyses.