SPECIAL FEATURE: OVERVIEW ARTICLESustainability science: bridging the gapbetween science and societyInnovation for sustainability: toward a sustainable urban futurein industrialized citiesJi Han•Psyche Fontanos•Kensuke Fukushi•Srikantha Herath•Niko Heeren•Vincenzo Naso•Claudio Cecchi•Peter Edwards•Kazuhiko TakeuchiReceived: 7 October 2011 / Accepted: 20 December 2011 / Published online: 18 January 2012ÓSpringer 2012AbstractAchievingasustainableurbanfuturehasbecome an important focus globally. In this paper, threemajor themes of a sustainable urban future are presented:a low carbon society, cities in the context of an ageingpopulation and revitalization of the urban–rural fringe.Visions of these themes, in the context of highly industri-alized regions, are discussed. To achieve a low carbonsociety, the importance of technological innovations suchas new technologies and systems applied in buildings(homes and businesses), industries, and transportation areemphasized. To adapt to an ageing society, a compact cityis seen with responsive transport, infrastructure and ser-vices that cater to the needs of the elderly. To enhance theurban–ruralfringe,theintroductionofeco-industries,which can create opportunities for both sides, is proposed.KeywordsUrban sustainabilityÁLow carbon cityÁCompact cityÁAgeing societyÁUrban–rural fringeIntroductionThe world is becoming steadily more urban as peoplecontinue moving to cities and towns. According to theWorld Urbanization Prospects report, by the middle of2009,thenumberofpeoplelivinginurbanareas(3.42 billion) had surpassed the number living in ruralareas (3.41 billion) (United Nations2009). As of 2009,already about 82% of North American populations live inurban areas, as do almost 80% of people in Latin Americaand the Caribbean as well as more than 70% of people inEurope and Oceania (Fig.1a). In both Africa and Asia,urban dwellers represent about 40% of the total population.By2050,theworldurbanpopulationisexpectedtoincrease by 84%, from 3.4 billion in 2009 to 6.3 billion bymid-century. There are, however, significant variationsbetween individual countries, and some major disparities inthe level of urbanization remain among developing ones.Figure1b shows the top 30 most populous countries, wheremore than three-quarters of urban dwellers lived in 2009.By 2050, 29 of the 30 most populous countries in 2009 willhave more than 50% of people living in urban areas.In addition, there is a continuing trend towards ever-largerurbanagglomerations.In2009,therewere21megacities in the world, each with at least 10 millioninhabitants, accounting for 9.4% of the world urban pop-ulation. Megacities come about because of the fusion ofseveral cities or urban localities that are linked functionallyand form an urban agglomeration. It is projected that thenumber of megacities will increase to 29 in 2025, and theywill be habited by 10.3% of the world urban population.