Given the intensification of environmental challenges and the decisive role of the agricultural sector in achieving sustainable development, this study aims to explain the link between agricultural support policies and carbon dioxide emissions in the Iranian economy. For this purpose, time series econometric frameworks including vector autoregressive regression (VAR) are used and the period of the first to fifth economic, social and cultural development plans of the country is analyzed. The results of the estimates indicate the existence of a two-way causal relationship between the Total Support Estimation for the Agricultural Sector (TSE) and carbon dioxide emissions; this means that support policies can affect the trend of pollutant emissions and, at the same time, changes in carbon dioxide emissions are also partly associated with changes in support. However, the intensity of the environmental variable’s impact on support decisions is estimated to be much weaker, indicating that environmental considerations do not yet have a prominent place in the agricultural support policy-making process and that the main priority is still focused on production and economic goals. Based on these findings, the study emphasizes the need to redesign support policies so that environmental criteria are systematically integrated into them. Establishing systematic systems for monitoring and evaluating the environmental impacts of agricultural policies, modifying the support mix in favor of low-carbon technologies and inputs, and developing educational programs in the field of sustainable agriculture alongside financial support are among the key recommendations of this study. Overall, the research results can provide an analytical framework for reviewing support policies and moving towards a low-carbon and sustainable development model in Iranian agriculture.