Toward climate-smart agriculture in Iran: A six-decade life cycle assessment of 17 crops across four climatic zones

Agriculture in Iran operates under acute water scarcity, climate stress, and reliance on input-intensive practices that amplify environmental pressures. This study presents the first long-term, spatially explicit life cycle assessment (LCA) of 17 major crops across four climatic zones from 1960 to 2022. Results reveal highly heterogeneous environmental burdens across crop groups and regions. Cereal systems in very dry zones generated extreme greenhouse gas emissions exceeding 9000 kg CO2 eq ton−1 in 2017, while oilseeds emerged as persistent hotspots, with acidification intensities rising more than 250-fold and abiotic resource depletion exceeding 200-fold in humid climates. Pulses and tubers also exhibited sustained surges in human toxicity and aquatic ecotoxicity, particularly under humid and semidry conditions. By contrast, cereals and forages in arid regions displayed significant improvements, with eutrophication and ecotoxicity potentials declining by up to 97%. Sensitivity and regression analyses confirmed diesel fuel, electricity, and nitrogen fertilizer as the dominant drivers of environmental impacts, with climate-specific variation in the magnitude and direction of effects. These findings emphasize that generalized policies are inadequate and that targeted, region-responsive strategies are required. Recommended interventions include scaling up precision agriculture, enforcing strict nutrient and pesticide management, and promoting low-carbon technologies. Despite limitations—such as reliance on static emission factors due to the lack of regionally calibrated life cycle inventory data—this work provides robust evidence to guide policymakers, planners, and sustainability scientists. The novelty of this study lies in its unprecedented integration of six decades of crop- and climate-specific data into a unified LCA framework, offering actionable insights for designing adaptive, regionally tailored agricultural policies that advance both national food security and global climate goals.