Purpose: Since green space becomes more significant in the greenhouse gas reduction, this study seeks to propose the potential green area impact that mean expected amounts and impacts of green space on land uses in the future in the planning phase. Method: To calculate the potential green areas impact, this study analyzes current characteristics of green spaces using land use spatial data and normalized difference vegetation index (NDVI) raster data. Five cities planned and developed in the 1990s and 2000s in Korea were selected, and the values of potential green area impact were calculated for each land use. The spatial unit used in the calculation was a 10 by 10 m unit cell considering the spatial resolution of NDVI raster data and combining spatial and raster data in the cell unit. Result: This study proposed "potential green area impact", a value that quantifies the potential land use ability to increase green areas for carbon absorption in the future. This potential green area impact is expected to be a criterion to develop guidelines of green space and to assess planning schemes of green space in urban land use plans to reduce greenhouse gases.