Urban Development Policy Making

Urban Development Policy Making

Climate Change Adaptation Policy in Tehran: Reinterpreting Spatial Precipitation Patterns over the Next 20-Year

Document Type : Original Article

Authors
Mohammad Reza Farzaneh 1
Mohammad Abdolhosseini 2
1 Assistant Prof. at Research Group of Environmental Engineering and Pollution Monitoring, Research Center for Environment and Sustainable Development, RCESD, Tehran, Iran
2 Assistant Professor, Water Engineering Department the Director of Educational Affairs, Gorgan University of Agricultural Sciences and Natural Resources (www.gau.ac.ir), Gorgan, Golestan Province, Iran
10.22034/judpm.2026.568604.1078
Abstract
The development of the Tehran metropolis requires adherence to spatial planning and resource capacity, especially hydrological limits. This study analyzes the impacts of climate change on precipitation distribution in Sub-basin 4133, which affects Tehran's urban policymaking. Given limited high-altitude observational data, TerraClimate reanalysis data were validated (R^2 > 0.85). Precipitation patterns from the past 70 and 20 years were studied, and future changes under four Shared Socioeconomic Pathways (SSPs) were projected using the median of five CMIP6 models with the Change Factor downscaling method. Results show a "spatial contraction of high-precipitation zones" in the last 20 years, decreasing the basin's hydrological inflow. Future projections indicate an inevitable precipitation decline even under the sustainable scenario (SSP1-2.6), with the pessimistic scenario (SSP5-8.5) predicting a severe water resource collapse in northern highlands (below 190 mm). This, potentially worsened by Tehran's Urban Heat Island (UHI), could lead to destructive flash floods, reduced soil permeability, compromised groundwater recharge, and increased land subsidence in southern districts. The findings underscore the critical need for urban regeneration to implement the "Sponge City" model and update spatial planning documents according to the basin's revised ecological capacity.
Keywords
Adaptation Policy
Climate Change
Climate resilience
Tehran
Subjects
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Urban Development Policy Making
Volume 3, Issue 2
Summer 2026
Pages 201-211

  • Receive Date 28 November 2025
  • Revise Date 29 December 2025
  • Accept Date 27 February 2026
  • Publish Date 01 June 2026