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China is the country with the most population in the world, and its climate is extremely diverse due to tremendous differences in latitude, longitude, and altitude, ranging from tropical in the far south to subarctic in the far north and alpine in the higher elevations of the Qinghai-Tibetan Plateau. Accurate assessment of its modern climate change is conductive to addressing global warming threat. Along with the development of Past Global Changes (PAGES) research, the focus has changed from paleo-climate reconstructions to using paleo-data for assessing the present and predicting the future. Previous studies have been devoted to climate change assessment using modern climate observations and simulations. This paper presents a new assessment approach based on the mid-Holocene, which provides a naturally oriented warming that can be compared to modern human-made global warming. A variety of climatic data, including modern observations, paleo-climate records, CMIP5 (Coupled Model Intercomparison Project Phase 5) and PMIP3 (Paleoclimate Modelling Intercomparison Project 3) simulations, as well as lake level models, were applied in this synthesis. Numerical climate classification was introduced to evaluate climate change impacts to Chinese climate zones on various time scales. The results show that winter and summer seasons have different response to the naturally oriented mid-Holocene warming but human-made global warming makes the warming trend appear in all seasons. Temperate and continental dry winter climates expand dramatically during the mid-Holocene warm period; however, the future global warming could have few impacts to Chinese climate zones. Furthermore, the East Asian summer monsoon was strengthened obviously by the mid-Holocene warm climate and strong low-latitude insolation. There is no consistent trend both for the winter and summer monsoon on the background of human-made global warming. In this study, a new benchmark was established based on paleo-climate to evaluate the impacts of human-made global warming. [ABSTRACT FROM AUTHOR]

As the global climate change and the rapid progress of urbanization, the frequent occurrence of flooding disasters and non-point source pollution seriously threaten the sustainable development of modern cities. To alleviate these problems, China started to pilot construction of the "Sponge City" (SPC). Over a decade, it has attracted public attention, supports, and participations. The paper presents a literature review of sponge city construction (SPCC) process (planning, design and construction) as well as the assessment of SPC, including: operation, maintenance, and effectiveness. Research gap and future works are also proposed. The paper offers some tactics for SPCC, including: 1) in the planning and construction stage of SPC, the goals and systematic plans should be formulated according to local water-environmental conditions. The drainage plan should cover the strategy to dispose runoff volumes at sources and the ultimately goal for flood mitigation. The drainage design involves the combination of various green and grey infrastructures; 2) It is important to identify monitoring methods and hydrological models which can be used to assess the performance of a SPC. With adequate field data, all models and methods should be calibrated for not only runoff quantity and quality control but also the alleviation of urban heat island effects, including the base flows and local groundwater table; 3) Based on the regional field data, it is necessary to standardize regional design parameters, construction material specifics, and maintenance scheme and schedule that would significantly affect the facility's infiltrating and filtering processes, therefore, a regular maintenance program should be initiated to monitor the operations of the as-built facilities according to local climate conditions. The paper evaluated several maintenance methods for ten typical facilities to provide a reference for the operation and maintenance of facilities in SPCC. • The sponge city construction (SPCC) and design methods were introduced in detail. • Scientific and reasonable assessment can better guide the SPCCs. • The sponge city (SPC) facilities can be a better way to control stormwater runoff. • Monitoring and simulation method are equally important for assessing SPC effect. • A maintenance program should be initiated to monitor the operations of SPC facility. [ABSTRACT FROM AUTHOR]

Climate warming and subsequent climate extremes have a wide impact on ecosystems and economic society. Scientifically quantitative assessment on climate change risks is an urgent issue attracted the attention of academics and decision-makers. In this paper, the theory of climate change risks was sorted out based on the three component elements of hazard, vulnerability, and exposure. Moreover, the idiomatic assessment methods and their applicability were systematically summarized. Comprehensive analysis found that the impacts of climate change generally showed a negative trend that was more harm than benefit, and further warming would aggravate the risk over China which was manifested to be more prominent in some sensitive sectors and key regions to climate change. Accessible management of the climate change risk should be engaged in effectively improving the methods of comprehensive identification, strengthening the mechanism and quantitative assessment, recognizing the temporal and spatial variation of components related to climate change risk, and reducing the uncertainty of climate change projection. • Theoretical framework of climate change risk was formed based on hazard, vulnerability, and exposure. • Assessment methods of climate change risk and their applicability were systematically summarized. • Climate change risk levels were analyzed in sensitive sectors and key regions over China. • In China, impacts of climate change were more harm than benefit while more warming was very likely to aggravate the risk. [ABSTRACT FROM AUTHOR]