According to the National Statistical Office (NSO), Phuket receives a large and increasing number of visitors each year, generating revenue and assisting in the development of both the local and the national economies. The impact of the increase in tourist numbers visiting Phuket is not only economic, but also social and environmental. The most noticeable changes in urban areas are the extreme levels of traffic congestion, increases in living expenses and a loss of green areas. This rapid and largely haphazard development is causing concern among the citizens of Phuket as they fear irreversible damages that could ruin the tourism industry in the long term. This paper presents a study conducted using geographic information system (GIS) as a tool to determine changes in land use and the carbon stored in soil from 2000 to 2013. On the basis of this information, the trend of the tourism carrying capacity, green space and global warming potential from the release of CO₂ from the soil surface can be analysed to assess the environmental status of the tourism industry in Phuket. The data show a negative trend requiring the enactment and implementation of stricter legislation for the management of tourism and the environment in Phuket.