銭 学鵬

林祥偉、周瑋生、銭学鵬、仲上 健一

A secured supply of clean water and sanitation relies on material- and capital-intensive municipal infrastructures, and thus requires a large quantity of material stocks. Major infrastructures sustaining the municipal water cycle from water supply to sewage management in China were probed for the period 1980–2050. The infrastructures proliferated rapidly in Chinese cities during the past three decades. The annual water supply capacity climbed from 11 to 100 km3, the sewage treatment capacity soared from 1.1 to 50 km3. To meet the demand of increasing urbanization, these infrastructures may have to more than doubly expand by 2050. Up to 3.3 gigatonnes (Gt) of construction materials, including 170 megatonnes (Mt) iron and steel and nearly 400 Mt cement (approximate to 10% of the global steel and cement production per annum), may be used to build up the infrastructure stocks. An indicator of material stock efficiency was devised to estimate potential and practical services per material stocks in the infrastructures can provide. Key findings include: (i) The conventional network-based water and sewage infrastructures might perform a declining material stock efficiency over the long run. (ii) The stock-based efficiency of the municipal infrastructures decreased by 25% from its peak in the early 1990s. It is driven down by the fact that pipe networks and sewage facilities are more material-intensive and usually developed behind water works. (iii) Nearly a half of the water supply capacity and 20% of the sewage treatment capacity were underutilized, leading to an evident gap between the potential and practical efficiency. The gap can be minimized by improving the utilization of the infrastructure's installed capacity.

A better understanding of the economy-material-emissions nexus is fundamental in order to reveal the interactions between human development and the natural environment, and more importantly, to design integrated de-carbonization and de-materialization policies. In this paper, we conducted a decoupling analysis of fossil fuel-induced CO2 emissions and in-use material stocks in infrastructure to economic growth at the provincial level in China and investigated the trilateral causal relationships among the three indicators. The results show that the average elasticity of CO2 emissions and material stocks to economic growth was smaller than 1, representing a status of relative decoupling. However, in many less developed provinces in central and western China, we observed increasing trends of elasticity in the past three decades, which suggest their economic growth became more tightly linked to CO2 emissions and the accumulation of material stocks. Granger tests suggest that in the long run there existed a unidirectional causality running from CO2 emissions, economic growth and urbanization to material stocks. In the short run, a bi-directional causality between CO2 emissions and economic growth and a unidirectional causality from material stocks to CO2 emissions were detected. Policy implications for the de-carbonization and de-materialization transition include enhancing renewable energy utilization, upgrading industries to less carbon-intensive ones, developing compact cities, prolonging the lifespan of infrastructure, and strengthening the life-cycle carbon management of infrastructure.

Global warming, mainly due to anthropogenic greenhouse gas emissions, has a devastating effect on our living planet. To combat it and foster a low-carbon society, contributions from the sports community are needed. Accordingly, the concept of ‘green sports’ has emerged, calling for green performance of sports infrastructure, green production in sports manufacturing, and green awareness of sports community. In this respect, Japan, as a leader in both Asian sports and worldwide sustainable development, has valuable experiences, including widespread stakeholders’ participation, substantial efforts, and outstanding achievements. Inspired by Japan’s examples, this study not only summarises mainstream recommendations for the development of green sports, but also presents two innovative proposals – linking green sports with market-based flexibility mechanisms and promoting environmental education through sports celebrities – and the prospects for these approaches. This article could be used by worldwide sports community as reference for making contributions to the establishment of a low-carbon society.