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The carbon balance in urban areas has become a major research challenge and a principal policy concern in efforts to address anthropogenic climate change. Rapid urbanization and industrialization in China urge the search for integrated strategies to mitigate and adapt to climate change, which not only limit to traditional infrastructure sectors, but also cover urban green infrastructure, because plants and soils function as carbon sinks through biotic sequestration. This study presents a nationwide study about how urban green infrastructure could contribute to the carbon balance in 35 major Chinese cities. By the end of 2010, the total area of urban green spaces (the dominant components of urban green infrastructure) accounts for 6.38% of the total land area of these cities and represented 51.7% of the total urban green spaces of all 657 cities in China. Based on empirical data from the literature, the total amount of carbon stored in the vegetation of the urban green infrastructure of 35 cities was estimated at 18.7 million tons, with an average carbon density of 21.34 t/ha. In 2010, the amount of carbon sequestration totaled 1.90 million tons with an average carbon sequestration rate of 2.16 t/ha/year. Collectively, only 0.33% of the carbon emissions from fossil fuel combustion can be offset, ranging from 0.01% in Hohhot to 22.45% in Haikou. Nevertheless, the dominance of young vegetation stands in Chinese urban green infrastructure suggests this small carbon sequestration efficiency could become substantial in the near future, given that appropriate policies and management practices are adopted to promote urban green infrastructure for climate change mitigation and adaptation. [ABSTRACT FROM AUTHOR]

Abstract: Climate change was not on the policy agenda in Hong Kong before 2007. In 2010, a consultation document, Hong Kong’s Climate Change Strategy and Action Agenda, was published proposing a voluntary carbon intensity reduction target of 50–60% by 2020 (from the 2005 level). This review attempts to understand why there was a sudden shift to climate issues and whether the proposed strategy, actions and targets are appropriate to the climate change challenges faced by the city. Through synthesizing existing literature on climate change at the city level, a framework outlining possible actions at the strategic, knowledge accumulation and implementation phases is developed to position Hong Kong’s experience. It is found that Hong Kong’s move towards climate change is strongly affected by China’s efforts. The city is facing some real climate change threats. However, while the carbon intensity reduction target looks impressive, it is actually too modest for the city’s developed economy. The city needs to reflect critically on its economics-first strategy and undertake more refined vulnerability studies and risk assessments to identify spatially and sectorally-specific adaptation measures. To be a responsible global citizen and to pursue sustainable development, Hong Kong needs more concerted and comprehensive efforts to combat climate change. [Copyright &y& Elsevier]