Peri-urbanization, land teleconnections, and the equality of ecological exchange: An emergy approach

Abstract

Urbanization is not only accompanied by local land use change, but also causes land use changes in distant places and affects the socio-ecological systems there. Urban land teleconnections (ULT) was introduced as a conceptual framework to link urbanization and land use changes of distant areas in the past, which have been generally ignored. ULT has also been proposed for use in investigating the equity principle of urban sustainability. The unequal exchange between an urban system and distant areas could become underlying causes that result in land use change in distant areas in the future. This study provides two case studies to demonstrate how land use processes are connected through peri-urbanization of Taipei and its resource inflow areas and the implications of the equality of ecological exchanges are discussed. The first case considers vegetable and fruit products from Changhua, Yunlin, and Chiayi Counties (the Chang-Yun-Chia area) of central and southern Taiwan, and the second case considers cement from Hualien in eastern Taiwan. To implement analysis of ULT, emergy synthesis was used to quantify the flow of materials between Taipei and the distant areas providing raw materials for food and construction and to assess the fairness and equality of the exchange. The results indicate that agricultural products or cement from distant areas tend to have low emergy exchange ratios when sold to Taipei markets. This phenomenon results from the fact that money is paid for human services and not for the work of nature that made the products. The low emergy exchange ratio of agricultural products caused land conversion in the Chang-Yun-Chia area. The low emergy exchange ratio of cement not only hurt the local economy of Hualien, because when it is exchanged more emergy of cement leaves the region than is returned in the buying power of the money received for it. Further inequality results, because the high environmental loading of cement extraction impacts the local Hualien system. Using empirical research on the application of the ULT theory to regional/local levels, the impact of the Taipei Metropolitan Area on the Chang-Yun-Chia and Hualien areas not only verifies the Taipei’s ULT phenomenon, but also clarifies the research gaps in the application of ULT theory.