Given the current trends, it seems obvious that temperatures and atmospheric carbon dioxide levels will rise over the coming years. To deal with climate change, a gradual transition to more sustainable viticulture operations is required. It seems necessary to carry out accurate local studies for future projections. The purpose of the current study was to choose the best grape production system in Jowzan Valley, Malayer, Iran. This region was registered by FAO as a Globally Important Agricultural Heritage System (GIAHS) in 2018. This study seeks to answer the question: if climate change has occurred in the Malayer region, which of the traditional and trellis systems is more sustainable from economic, energy, and environmental aspects? The sixth phase of the Coupled Model Intercomparison Project (CMIP6) was used to project the climate parameters of Malayer in the past and the future. The output of climate models based on rainfall, temperature, and wind (as factors influencing grape yield) in the observation period of 1992–2021 (the base period) and forecasting the future period of 2021–2100 under three scenarios (SSP1-26, SSP2-45, and SSP5-85) were obtained. The determination of hotspots in terms of cost, energy, and environment for two production systems was done with the approaches of material and energy flow cost accounting (MFCA) and life cycle assessment (LCA). The results of these two approaches help us know which of the two systems are currently more sustainable in terms of economic, energy, and environmental aspects. Grape production in 1 hectare was chosen as a functional unit (FU). The system boundary included the foreground processes that the farmer was directly involved in managing. Grape data were collected in the crop year of 2021–2022 from the vineyards of Jowzan region. According to results, under SSP1-26, SSP2-45, and SSP5-85 scenarios, the annual mean temperature is expected to rise at rates of 0.27, 0.477, and 0.82 °C 10a−1 in the future (2021–2100), respectively. From an economic point of view, labor was recognized as the main input. By changing the system from traditional to trellis, production costs can be expected to be halved. The main hotspot in terms of negative products was the loss of grapes during production or harvesting. Such conditions were also true in terms of energy. From the environmental aspect, on-farm emissions and electricity were identified as hotspots. These effects are greatly reduced in the trellis system compared to the traditional system. In the case of changing the system from traditional to trellis, these effects can be reduced to a reasonable extent by improving the efficiency of irrigation and fertilizer distribution through the irrigation system. According to the results obtained from the climate scenarios as well as the results of the economic, environmental, and energy evaluation of the two production systems, it can be concluded that the use of the trellis system can be more sustainable than the traditional system.
