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1.
China’s tourism industry has witnessed rapid progress in recent years, and is now an important part of global tourism in dealing with climate change. Within a framework of Pressure-State-Response (PSR), this paper focuses on the emission reduction pressure, carbon emission status, and responses of stakeholders in China’s tourism industry. Findings include: 1) The central government’s strategy and rapid growth of the industry scale exert rising pressure on China’s tourism to reduce carbon emissions. 2) Carbon emissions of China's tourism account for 13%-14.6% of global tourism, and about 3% of China’s emissions overall. Chinese tourists’ per capita carbon emission is lower than half of the global level. 3) The Chinese government attaches great importance to energy-saving and carbon emission reduction. In the tourism industry, documents, standards and other regulative measures have been issued to ensure that business practitioners set up green operational and managerial systems. In the field of tourism transportation, China's high-speed rail, new energy vehicles, and urban shared bicycles, have developed very rapidly in recent years, and they have effectively reduced the carbon emissions in traveling. Furthermore, this paper finds that Chinese tourists already have awareness and willingness for low-carbon tourism.  相似文献   
2.
The extent to which forests, relative to shorter vegetation, mitigate flood peak discharges remains controversial and relatively poorly researched, with only a few significant field studies. Considering the effect purely of change of vegetation cover, peak flow magnitude comparisons for paired catchments have suggested that forests do not mitigate large floods, whereas flood frequency comparisons have shown that forests mitigate frequencies over all magnitudes of flood. This study investigates the apparent inconsistency using field-based evidence from four contrasting field programmes at scales of 0.34–3.1 km2. Repeated patterns are identified that provide strong evidence of real effects with physical explanations. Magnitude and frequency comparisons are both relevant to the impact of forests on peak discharges but address different questions. Both can show a convergence of response between forested and grassland/logged states at the highest recorded flows but the associated return periods may be quite variable and are subject to estimation uncertainty. For low to moderate events, the forested catchments have a lower peak magnitude for a given frequency than the grassland/logged catchments. Depending on antecedent soil saturation, a given storm may nevertheless generate peak discharges of the same magnitude for both catchment states but these peaks will have different return periods. The effect purely of change in vegetation cover may be modified by additional forestry interventions, such as road networks and drainage ditches which, by effectively increasing the drainage density, may increase peak flows for all event magnitudes. For all the sites, forest cover substantially reduces annual runoff.  相似文献   
3.
东天山造山带的图拉尔根镁铁-超镁铁杂岩体为一个早古生代长期活动的幔源岩浆通道,大型铜镍钴硫化物矿体赋存于Ⅰ号超镁铁质岩体的顶部,不同类型岩石中辉石矿物的流体挥发份化学组成以H2O为主(平均91%,5400.4mm3/g),其次为H2(2.0%)、H2S(2.3%)和CO2(2.1%);赋矿角闪橄榄岩中CO2和H2S含量最高,辉长岩中流体挥发份含量低于辉石橄榄岩和橄榄辉石岩等岩浆早期结晶的岩石。CO2和CH4δ13C值位于地壳与甲烷氧化的范围内,甲烷同系物的碳同位素组成具有正序分布模式,部分样品(TLG512)释出的CH4和C2H6具有较重的δ13C值和反序分布特征。表明I号岩体不同类型岩石可能是不同期次岩浆活动的产物,成矿岩浆具有富H2O和H2S的特征,可能起源于被流体交代的亏损地幔源区,混染壳源组分可能为俯冲板片来源蚀变沉积有机质组分。  相似文献   
4.
2020年3月30日,四川省凉山州西昌市经久乡发生森林大火,山火燃烧后形成的山火灰和烧焦土体在强降雨作用下极易启动形成泥石流,给西昌市泸山、琼海景区生态环境及当地百姓生命财产安全带来潜在地质灾害风险。以西昌市安哈镇响水沟左岸3#支沟为例,采用野外调查、无人机航拍、地球物理探测、现场及室内实验等手段,对2020年5月1日该沟发生的火后泥石流流体特征、动力学参数及成因机制等开展研究,系统分析了山火及降雨过程对该次火后泥石流形成的影响机制。该成果可为系统认识西昌泸山“3·30”山火地区火后泥石流的运动特征、物源规模、激发雨量及其发展趋势研判提供科学参考。  相似文献   
5.
中国城市抗御地震灾害研究的发展与实践   总被引:1,自引:1,他引:0  
城市是社会发展的产物,它具有人口密集、经济发达、基础设施集中等特点。城市安全一直是人们普遍关心的问题,城市地震安全受到政府和社会的广泛关注,并且是学术界研究的热点问题之一。唐山大地震后,在反思惨痛震害教训的同时,中国政府和学术界开始了长达40余年的城市抗御地震灾害的研究与实践,形成了有中国特色的城市抗震防灾技术和方法。本文简要地归纳了破坏性地震对城市的影响,从我国先后开展的城市抗震防灾规划、防震减灾规划和韧性城市3个方面系统地总结了中国城市抗御地震灾害研究和实践的发展历程,讨论和评述了在这一研究领域存在的问题。本文对韧性城市的定义、研究内容、特征、评价指标和方法进行了较为详细的介绍,在此基础上,提出了在城市抗震中应重点加强研究的5个方面的问题和今后的研究方向。  相似文献   
6.
Passive tuned mass dampers (TMDs) are widely used in controlling structural vibrations. Although their principle is well established, the search for improved arrangements is still under way. This effort has recently produced an innovative paradigm of bidirectional pendulum TMD (BTMD) that, moving along a specially designed three-dimensional (3D) surface, can simultaneously control two in-plane orthogonal structural modes. In existing versions of BTMDs, energy dissipation is provided either by ordinary horizontal viscous dampers or by an original arrangement of vertical friction dampers. In this paper, a new paradigm is proposed, in which energy dissipation comes from the tangential friction arising along the pendulum surface out of an optimal spatially variable friction coefficient pattern. Within this paradigm, if the friction coefficient is taken proportional to the modulus of the pendulum surface gradient, the dissipation model results nonlinear homogeneous in the small-displacement domain, and the performance of the absorber, herein called the homogeneous tangential friction BTMD (HT-BTMD), results independent from the excitation level. The present work introduces this concept, derives the analytical model of the HT-BTMD, establishes a method for its optimal design, and numerically verifies its seismic effectiveness in comparison with viscously damped devices. The validity and feasibility of the concept are demonstrated through experimental tests on a small-scale lab prototype, which also show the efficacy of a stepwise approximation of the homogeneous friction pattern. The new device proves a competing alternative to existing BTMDs, and homogeneous tangential friction proves a promising new paradigm to provide pendular systems with amplitude-independent structural damping.  相似文献   
7.
Biodiversity loss, climate change, and increased freshwater consumption are some of the main environmental problems on Earth. Mountain ecosystems can reduce these threats by providing several positive influences, such as the maintenance of biodiversity, water regulation, and carbon storage, amongst others. The knowledge of the history of these environments and their response to climate change is very important for management, conservation, and environmental monitoring programs. The genesis of the soil organic matter of the current upper montane vegetation remains unclear and seems to be quite variable depending on location. Some upper montane sites in the very extensive coastal Sea Mountain Range present considerable organic matter from the late Pleistocene and other from only the Holocene. Our study was carried out on three soil profiles (two cores in grassland and one in forest) on the Caratuva Peak of the Serra do Ibitiraquire (a sub-range of Sea Mountain Range – Serra do Mar) in Southern Brazil. The δ13C isotopic analyses of organic matter in soil horizons were conducted to detect whether C3 or C4 plants dominated the past communities. Complementarily, we performed a pollen analysis and 14C dating of the humin fraction to obtain the age of the studied horizons. Except for a short and probably drier period (between 6000 and 4500 cal yr BP), C3 plants, including ombrophilous grasses and trees, have dominated the highlands of the Caratuva Peak (Pico Caratuva), as well as the other uppermost summits of the Serra do Ibitiraquire, since around 9000 cal yr BP. The Caratuva region represents a landscape of high altitude grasslands (campos de altitude altomontanos or campos altomontanos) and upper montane rain/cloud forests with soils that most likely contain some organic matter from the late Pleistocene, as has been reported in Southern and Southeastern Brazil for other sites. However, our results indicate that the studied deposits (near the summit) are from the early to late Holocene, when somewhat wetter and warmer conditions (since around 9000 cal yr BP) enabled a stronger colonization of the ridge of Pico Caratuva by mainly C3 plants, especially grassland species. However, at the same time, even near the summit, the soil core from the forest site already presented the current physiognomy (or a shrubby/elfin or successional forest), indicating that the colonization of the neighboring uppermost saddles and valleys were probably populated mainly by upper montane forest species.  相似文献   
8.
海水中的颗粒有机碳(POC)与生物的生命过程、初级生产力关系密切,是海洋食物链中重要的物质基础和能量来源,因此POC的分布特征可以有效反映其生物地球化学环境。利用中国第33次南极考察期间(2016年12月至2017年1月)在南极半岛邻近海域采集的海水颗粒物样品,研究POC的空间分布特征及其影响因素。结果表明,斯科舍海0—200 m的POC浓度范围为7.44—193.52μg·L~(-1),平均浓度为(48.84±35.09)μg·L~(-1);南斯科舍海岭0—200 m的POC浓度范围为9.13—62.17μg·L~(-1),平均浓度为(29.76±14.12)μg·L~(-1);鲍威尔海盆0—200 m的POC浓度范围为5.87—270.72μg·L~(-1),平均浓度为(48.57±38.92)μg·L~(-1)。表层POC高值出现在斯科舍海区和鲍威尔海盆区,而低值出现在海岭区,与叶绿素a(Chla)的变化趋势一致,与营养盐的变化趋势相反。垂向分布上,各个区域POC平均浓度随深度的增加而减少,鲍威尔海盆和斯科舍海POC最高值都出现在25 m层。分析结果表明光合浮游植物是研究海域POC的主要来源, POC的主要影响因素为温度、水团混合以及海冰环境。斯科舍海与鲍威尔海盆整体非生命POC占比高,可能是由于高磷虾生物量、海冰碎屑以及陆源输入的干扰;南斯科舍海岭整体非生命POC占比低。  相似文献   
9.
Large carbon cycle perturbations associated with the Middle Permian (Capitanian) mass extinction have been widely reported, but their causes and timing are still in dispute. Low resolution carbon isotope records prior to this event also limit the construction of a Middle Permian chemostratigraphic framework and global or local stratigraphic correlation, and hence limit our understanding of carbon cycle and environmental changes. To investigate these issues, we analyzed the 13Corg values from the Middle Permian chert-mudstone sequence (Gufeng Formation) in the Lower Yangtze deep-water basin (South China) and compared them with published records to build a chemostratigraphic scheme and discuss the underlying environmental events. The records show increased δ13Corg values from late Kungurian to early Guadalupian, followed by a decrease to the late Wordian/early Capitanian. The early-mid Capitanian was characterized by elevated δ13Corg values suggesting the presence of the “Kamura Event”: an interval of heavy positive values seen in the δ13Ccarb record. We propose that these heavy Capitanian δ13C values may be a response to a marked decline in chemical weathering rates on Pangea and associated reduction in carbonate burial, which we show using a biogeochemical model. The subsequent negative δ13C excursion seen in some carbonate records, especially in shallower-water sections (and in a muted expression in organic carbon) coincide with the Capitanian mass extinction may be caused by the input of isotopically-light carbon sourced from the terrestrial decomposition of organic matter.  相似文献   
10.
Individual countries are requested to submit nationally determined contributions (NDCs) to alleviate global warming in the Paris Agreement. However, the global climate effects and regional contributions are not explicitly considered in the countries’ decision-making process. In this study, we evaluate the global temperature slowdown of the NDC scenario (?T = 0.6°C) and attribute the global temperature slowdown to certain regions of the world with a compact earth system model. Considering reductions in CO2, CH4, N2O, BC, and SO2, the R5OECD (the Organization for Economic Co-operation and Development in 1990) and R5ASIA (Asian countries) are the top two contributors to global warming mitigation, accounting for 39.3% and 36.8%, respectively. R5LAM (Latin America and the Caribbean) and R5MAF (the Middle East and Africa) followed behind, with contributions of 11.5% and 8.9%, respectively. The remaining 3.5% is attributed to R5REF (the Reforming Economies). Carbon Dioxide emission reduction is the decisive factor of regional contributions, but not the only one. Other greenhouse gases are also important, especially for R5MAF. The contribution of short-lived aerosols is small but significant, notably SO2 reduction in R5ASIA. We argue that additional species beyond CO2 need to be considered, including short-lived pollutants, when planning a route to mitigate climate change. It needs to be emphasized that there is still a gap to achieve the Paris Agreement 2-degree target with current NDC efforts, let alone the ambitious 1.5-degree target. All countries need to pursue stricter reduction policies for a more sustainable world.  相似文献   
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