اثرات شهرنشینی جمعیتی، اقتصادی و محیط‌زیستی بر سیستم آب، غذا و انرژی در ایران

Background and Purpose: The pattern of living and settlement in Iran has undergone an unimaginable transformation during the last century. This pattern has reached the stage of urbanization from nomadism. This development has intensified the pressure on resources. To test this assumption, a comprehensive NU evaluation index system is developed.  This system encompasses five key dimensions: population, economy, space, society, and ecological environment, further enriching the research on NU. In this study, the amount of pressure caused by urbanization on water, energy, and food systems in different provinces of the country was evaluated.
Methodology: For this purpose, the descriptive and analytical method was used. The required data were obtained from the energy balance sheet, Iran Statistical Center, Central Bank, and Ministry of Energy. For the evaluation to be done accurately and reliably, an attempt was made to construct indicators related to urbanization in economic, spatial, social, and environmental dimensions. The collected data for each province of Iran were ranked by the entropy weighting method. Finally, using the fixed effects model, the consequences of each range were analyzed.
Findings and Discussion: Finally, using the fixed effects model, the consequences of each range were analyzed. The findings showed that urbanization affects the pressure on the water, energy, and food systems and can be shown as an inverted U-shaped curve. The current position of this relationship is that it has passed the turning point of the curve. The difference between regions should be related to their economic development levels. The main reason for this effect is that the central region contains four urban complexes with a very important level of economic development (including Tehran, Karaj, Qom, and Isfahan). High economic density leads to the spatial accumulation of human resources and financial capital and the knowledge spillover effect, and causes the spatial reconfiguration of production factors. In this situation, the cost of innovation has been significantly reduced, the efficiency of using resources has been improved, and the same conditions reduce the pressure on the water, energy, and food systems. Typically, when urbanization is growing, better educational opportunities are provided, and social and civic infrastructures are prepared to increase residents' environmental awareness and encourage them to adopt environmentally friendly behaviors. Water: The regression coefficient of the effect of urbanization on water is positive at the level of 5% and shows a high effect. The results show that this process intensifies the pressure on water resources. Energy: The regression coefficient determined the critical value of 0.246. Comparing this value with the average urbanization shows that the overall level of urbanization has exceeded the critical value. The negative relationship between the degree of urbanization and regional energy is confirmed. Food: The regression coefficient of urbanization with a critical value of 0.511 shows a significant U-shaped effect on food, but the overall level of urbanization has not exceeded the critical value. This indicates that urbanization at the current level has helped to reduce the pressure on the regional food system.
Conclusion: The estimated coefficients for population urbanization and social urbanization were 23.692 and 24.703, respectively. These coefficients have been confirmed at a significant level of 5% and 1%. It is clear that both significantly increase the pressure on the water, energy, and food systems, which, of course, is the effect of social urbanization more than the other. The estimated coefficients for economic urbanization and spatial urbanization were -217.82 and -67.895, respectively, both of which are statistically significant at the 1% confidence level. In terms of the absolute value of the coefficients, economic urbanization is greater than spatial urbanization, which shows that this phenomenon has the greatest effect on reducing the pressure on the regional water, energy, and food system. It is very important that although the estimated coefficient for environmental urbanization is negative (-5.5982), it is not statistically significant. So the main conclusions drawn in this paper are as follows: During the study period, the level of NU in various provinces in Iran showed a continuous upward trend, with the rate of increase slowing down. The impact of NU on WEFSP crossed the curve's inflection point; that is, the increase in NU level positively affected the mitigation of the WEFSP. These research findings remain valid even after undergoing a battery of robustness tests, indicating good robustness of the conclusions. The impact of NU on WEFSP exhibited regional heterogeneity and structural heterogeneity. NU had a significant inverted “U-shaped” effect on WEFSP in the western regions, while the impact on the remaining areas was not significant.