4361848
An evaluation of the ecological and environmental security on China’s terrestrial ecosystems
With rapid economic growth, industrialization, and urbanization, various ecological and environmental problems occur, which threaten and undermine the sustainable development and domestic survival of China. On the national scale, our progress remains in a state of qualitative or semi-quantitative evaluation, lacking a quantitative evaluation and a spatial visualization of ecological and environmental security. This study collected 14 indictors of water, land, air, and biodiversity securities to compile a spatial evaluation of ecological and environmental security in terrestrial ecosystems of China. With area-weighted normalization and scaling transformations, the veto aggregation (focusing on the limit indicator) and balanced aggregation (measuring balanced performance among different indicators) methods were used to aggregate security evaluation indicators. Results showed that water, land, air, and biodiversity securities presented different spatial distributions. A relatively serious ecological and environmental security crisis was found in China, but presented an obviously spatial variation of security evaluation scores. Hotspot areas at the danger level, which are scattered throughout the entirety of the country, were identified. The spatial diversities and causes of ecological and environmental problems in different regions were analyzed. Spatial integration of regional development and proposals for improving the ecological and environmental security were put forward.
8001853
Catastrophic shifts in ecosystems
All ecosystems are exposed to gradual changes in climate, nutrient loading, habitat fragmentation or biotic exploitation. Nature is usually assumed to respond to gradual change in a smooth way. However, studies on lakes, coral reefs, oceans, forests and arid lands have shown that smooth change can be interrupted by sudden drastic switches to a contrasting state. Although diverse events can trigger such shifts, recent studies show that a loss of resilience usually paves the way for a switch to an alternative state. This suggests that strategies for sustainable management of such ecosystems should focus on maintaining resilience.
152223772
Crises and Crisis Management: Integration, Interpretation, and Research Development
Organizational research has long been interested in crises and crisis management. Whether focused on crisis antecedents, outcomes, or managing a crisis, research has revealed a number of important findings. However, research in this space remains fragmented, making it difficult for scholars to understand the literature’s core conclusions, recognize unsolved problems, and navigate paths forward. To address these issues, we propose an integrative framework of crises and crisis management that draws from research in strategy, organizational theory, and organizational behavior as well as from research in public relations and corporate communication. We identify two primary perspectives in the literature, one focused on the internal dynamics of a crisis and one focused on managing external stakeholders. We review core concepts from each perspective and highlight the commonalities that exist between them. Finally, we use our integrative framework to propose future research directions for scholars interested in crises and crisis management.
129028445
Desertification in China: An assessment
Abstract Arid and semiarid China have experienced multiple arid phases throughout the Quaternary, and over the past five decades, there have been several periods with relatively high or low rates of desertification and rehabilitation. The causes of these changes and their historical trends have been debated by scientists because of their potentially huge significance for China, as well as for the global ecology and food supply. This paper reviews recent studies of desertification in different regions of arid and semiarid China. In general, the results of systematic monitoring, and analyses of the causes of desertification and the contemporaneous human impacts, suggest that desertification in China has been primarily caused by climate change, and particularly by strong wind regimes (with high sand transport potential) accompanied by decreased spring precipitation. Unfortunately, although numerous scientists have claimed that desertification in China is primarily due to human impacts; there is surprisingly little unassailable evidence to support this claim. The review presented in this paper show that desertification in China is likely to be controlled by climate change and geomorphological processes, even though human impacts have undeniably exacerbated their effects. Our arguments for both climate change and human activity as factors responsible for the observed changes in desertification rely primarily on inferences based on correlations between trends, thus future research must seek stronger and more direct evidence for the causal relationships that we have proposed as possibilities. This improved information is essential to provide a firm basis for future policy decisions on how best to combat desertification.
3104433
Status of metal accumulation in farmland soils across China: from distribution to risk assessment.
Increasing metal pollution has drawn broad public attention in China due to severe environmental quality deterioration. However, so far, there has been no study to survey metal accumulation in Chinese farmland soil at the national scale. In this study, we determined 11 metals in farmland soils across the Mainland China. Our results indicated the concentrations of Pb, Cd, Zn, and Cu (10.1-184.2, 0.082-1.31, 20.2-321.9, 8.2-515.9 mg/kg, respectively) were elevated above their reference values. Moreover, these metals followed a similar geochemical distribution pattern. The accumulation of Pb, Cd, Zn, and Cu in soils may be associated with human activities for soil fertility. Cadmium had the highest pollution index (PI) of 5.28, and the average hazard quotients (HQs) for all the metals were below 1. Hence, except for Cd, the metals in Chinese arable soils are comparatively safe. Results from this study may provide valuable information for agricultural soil management in China.
93307407
Spatial distribution, seasonal variation and regionalization of PM2.5 concentrations in China
In order to provide scientific support to policy makers in the regulation of PM2.5 pollution in China, it is important to accurately assess the current status, spatiotemporal characteristics and regionalization data for this air pollutant. An analysis of the pollution status of PM2.5 was conducted using daily averaged mass concentration data recorded in 74 cities in 2013 and 161 cities in 2014. The rotated empirical orthogonal function (REOF) method was applied to analyze this data. Results showed that the average annual PM2.5 concentration in urban areas of China is 62.2±21.5 µg/m3, and that the distribution is spatially heterogeneous. The North China Plain, middle and lower Yangtze River Plain, Si Chuan Basin and Guanzhong Plain had relatively high annual PM2.5 concentrations compared with the southeast coastal region, the Tibetan Plateau and the Yungui Plateau. PM2.5 mass concentrations tended to be higher in winter than in summer, however, the data for many cities showed a small peak in concentrations from May to July. An analysis of the spatial correlation of PM2.5 indicated a significant influence of topographic conditions. A lower correlation was observed where terrain features varied greatly. Based on the results of the REOF analysis and topographic characteristics, ten regions were identified in mid-eastern China, which could be considered as basic pollution prevention divisions for PM2.5; these include the North China Plain region, Pearl River Delta region, Jianghuai Plain region, middle Yangtze River Plain region, Northeast Plain region, Jiangnan coastal region, Si chuan Basin region, Qiantao Plain region, Guanzhong-Central Plain region and Yungui Plateau region. Seasonal variations in the regionalization data were observed, especially for the North China Plain and Pearl River Delta regions. Among the ten regions identified in this study, the North China Plain, Guanzhong-Central Plain, middle Yangtze River Plain and Jianghuai Plain had relatively high PM2.5 mass concentrations in comparison with the others. Therefore, these regions should be considered as the key regions to target in developing PM2.5 pollution prevention strategies. This study improves the present understanding of the spatial distribution, seasonal changes and regional status of PM2.5 pollution in China and helps establish possible control strategies for the reduction of this air pollutant.
167964279
Changes and challenges: China's environmental management in transition
China's 12th Five-Year Plan (2011–2015) announces a shift to a new development model and a new green governance approach. Can we indeed identify a specific Chinese transition mode in moving from a monolithic economic growth path to a sincere green development model? To understand China's environmental management transition and address this question we assess whether and to what extent China has been shifting course in resource use and limiting environmental pollution. This review paper provides a comprehensive overview of the development of environmental management in China based on existing sources of information. Four major environmental challenges are identified for the future environmental management of the biggest emerging economy in the world.
96748748
Complexity of ecological restoration in China
Abstract Land degradation is a primary issue that affects environmental conservation and socioeconomic development. However, ecological restoration has complex and poorly understood consequences for the structure and composition of future ecosystems and socioeconomic systems. To illustrate the complexity of ecological restoration, we discuss the potential links between China's ongoing large-scale ecological restoration practices and the resulting changes of natural factors such as landscape characteristics, climate, and vegetation communities. These changes may lead to restoration difficulty when the goal is to rebuild a system that resembles the pre-disturbance state. Even though the intentions of ecological restoration may be good, it is necessary to harmonize the ecological effects with simultaneous and future social changes, thereby benefiting both nature and society. Any simplistic or extreme approach to ecological restoration is potentially dangerous because the long-term effects on nature and society are generally unknown, so careful monitoring will be required, particularly for large-scale projects.
152563167
Environmental Governance in China
1. Introduction: Environmental Governance in Transitional China 2. Economic Growth and Environmental Protection 3. Environmental Policy-Making Processes in China 4. Environmental Law Compliance in China 5. Urban Infrastructures: Water 6. Industrial Growth and Environmental Restructuring in China 7. Participation, Civil Society and NGOs 8. Energy Policy in China 9. Biotechnology Policy and Biosafety Politics in China 10. Epilogue
8535854
Novel methods to assess environmental, economic, and social sustainability of main agricultural regions in China
In China, dramatic changes of land use since 1980 have induced environmental and socioeconomic problems threatening food security. Therefore, improving sustainability of land use in China is of utmost importance, especially in agricultural regions. So far, few investigations have analyzed sustainability at small scales in China. Here, we propose a methodological framework for assessing the sustainability level of main agricultural regions in China on regional and county levels. We distinguish four sustainability categories: environmental, economic, social, and comprehensive sustainability. Two methods of measuring sustainability were used: (1) the balanced performance method that measures balanced performance among different aspects and (2) the aggregate achievement method that measures aggregate achievement of all aspects. Spatial variation maps of sustainability across counties were produced using a geographic information system, and the limiting factors in each region were identified. Results show that the two methods give highly different values of sustainability levels. The balanced performance method yields lower sustainability values ranging from 0.06 to 0.57, whereas the aggregate achievement method yields higher sustainability values ranging from 0.11 to 0.87. Such differences have not been addressed in previous studies. Using the balanced performance method, the Sichuan Basin is the most comprehensive sustainability region with a 0.05 level, while Xinjiang is the least comprehensive sustainability region with a 0.01 level. Using the aggregate achievement method, the middle reaches of the Yangtze River and Jianghuai region is the most comprehensive sustainability area with a 0.46 level, whereas South China is the least comprehensive sustainability area with a 0.31 level. Sensitivity analysis showed that Songnen and Sanjiang Plains were more sensitive to the indicator selection and aggregation rules. Scale effects were not observed for sustainability assessment at the regional level.
13855521
Comparing alternative approaches to measuring the geographical accessibility of urban health services: Distance types and aggregation-error issues
BackgroundOver the past two decades, geographical accessibility of urban resources for population living in residential areas has received an increased focus in urban health studies. Operationalising and computing geographical accessibility measures depend on a set of four parameters, namely definition of residential areas, a method of aggregation, a measure of accessibility, and a type of distance. Yet, the choice of these parameters may potentially generate different results leading to significant measurement errors.The aim of this paper is to compare discrepancies in results for geographical accessibility of selected health care services for residential areas (i.e. census tracts) computed using different distance types and aggregation methods.ResultsFirst, the comparison of distance types demonstrates that Cartesian distances (Euclidean and Manhattan distances) are strongly correlated with more accurate network distances (shortest network and shortest network time distances) across the metropolitan area (Pearson correlation greater than 0.95). However, important local variations in correlation between Cartesian and network distances were observed notably in suburban areas where Cartesian distances were less precise.Second, the choice of the aggregation method is also important: in comparison to the most accurate aggregation method (population-weighted mean of the accessibility measure for census blocks within census tracts), accessibility measures computed from census tract centroids, though not inaccurate, yield important measurement errors for 5% to 10% of census tracts.ConclusionAlthough errors associated to the choice of distance types and aggregation method are only important for about 10% of census tracts located mainly in suburban areas, we should not avoid using the best estimation method possible for evaluating geographical accessibility. This is especially so if these measures are to be included as a dimension of the built environment in studies investigating residential area effects on health. If these measures are not sufficiently precise, this could lead to errors or lack of precision in the estimation of residential area effects on health.
82730026
A framework for selecting indicators of bioenergy sustainability
A framework for selecting and evaluating indicators of bioenergy sustainability is presented. This framework is designed to facilitate decision-making about which indicators are useful for assess- ing sustainability of bioenergy systems and supporting their deployment. Efforts to develop sustain- ability indicators in the United States and Europe are reviewed. The fi rst steps of the framework for indicator selection are defi ning the sustainability goals and other goals for a bioenergy project or pro- gram, gaining an understanding of the context, and identifying the values of stakeholders. From the goals, context, and stakeholders, the objectives for analysis and criteria for indicator selection can be developed. The user of the framework identifi es and ranks indicators, applies them in an assess- ment, and then evaluates their effectiveness, while identifying gaps that prevent goals from being met, assessing lessons learned, and moving toward best practices. The framework approach emphasizes that the selection of appropriate criteria and indicators is driven by the specifi c purpose of an analysis. Realistic goals and measures of bioenergy sustainability can be developed systematically with the help of the framework presented here. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd
4654754
Environmental Pollution in China: Status and Trends
The state of China's environment is receiving attention from all over the world. This article reviews the current status and trends of environmental pollution in China. We argue that China is able to contain, and to some extent improve, air and water quality for the urban population at the local level. The situation is uneven when it comes to problems at the regional level. On the one hand, surface water quality in the South is improving and particle emissions are stable. On the other hand, nitrogen oxide emissions are increasing rapidly and sulfur oxide emissions have been on the rise until very recently, despite intense official pressure to bring sulfur emissions down. China's CO2 emissions have grown rapidly in recent years, causing global concern. However, we argue that future growth in CO2 emissions is likely to be slower. Overall, China appears to be following a path similar to the one taken by more industrialized countries.
86533158
Assessing environmental security in China
In recent decades, perspectives on the integrated social-ecological aspects of natural resource problems have become increasingly influential as traditional national security outlooks have expanded to include environmental and human concerns. However, China has not been influenced much by new environmental security frameworks. An overview of six main stressors - ecosystem degradation, food security, energy, water, urbanization, and climate change - that affect security in China reveals that current policies need to be reformed. China's ecosystems remain subject to widespread degradation, food supply is under stress, energy demand is growing rapidly, there are increasing conflicts over water quality and quantity, urbanization cannot proceed without fundamental environmental and social reforms, and climate-change impacts are projected to intensify. To resolve such security issues, China's leaders must depend less on technological solutions and should instead craft adaptive management reforms to address the lack of interdisciplinary problem-solving, low institutional capacity, and gaps between policy and implementation.
35300
China's water scarcity.
China has been facing increasingly severe water scarcity, especially in the northern part of the country. China's water scarcity is characterized by insufficient local water resources as well as reduced water quality due to increasing pollution, both of which have caused serious impacts on society and the environment. Three factors contribute to China's water scarcity: uneven spatial distribution of water resources; rapid economic development and urbanization with a large and growing population; and poor water resource management. While it is nearly impossible to adjust the first two factors, improving water resource management represents a cost-effective option that can alleviate China's vulnerability to the issue. Improving water resource management is a long-term task requiring a holistic approach with constant effort. Water right institutions, market-based approaches, and capacity building should be the government's top priority to address the water scarcity issue.
30302894
Contamination features and health risk of soil heavy metals in China.
China faces a big challenge of environmental deterioration amid its rapid economic development. To comprehensively identify the contamination characteristics of heavy metals in Chinese soils on a national scale, data set of the first national soil pollution survey was employed to evaluate the pollution levels using several pollution indicators (pollution index, geoaccumulation index and enrichment factor) and to quantify their exposure risks posed to human health with the risk assessment model recommended by the US Environmental Protection Agency. The results showed that, due to the drastically increased industrial operations and fast urban expansion, Chinese soils were contaminated by heavy metals in varying degrees. As a whole, the exposure risk levels of soil metals in China were tolerable or close to acceptable. Comparatively speaking, children and adult females were the relatively vulnerable populations for the non-carcinogenic and carcinogenic risks, respectively. Cadmium and mercury have been identified as the priority control metals due to their higher concentrations in soils or higher health risks posed to the public, as well as, arsenic, lead, chromium and nickel. Spatial distribution pattern analysis implied that the soil metal pollutions in southern provinces of China were relatively higher than that in other provinces, which would be related to the higher geochemical background in southwest regions and the increasing human activities in southeast areas. Meanwhile, it should be noticed that Beijing, the capital of China, also has been labeled as the priority control province for its higher mercury concentration. These results will provide basic information for the improvement of soil environment management and heavy metal pollution prevention and control in China.
130221968
Geochemical evaluation of land quality in China and its applications
Abstract The evaluation of land quality is fundamental for land use planning. The geochemical evaluation of land quality in China is a basic part of the Multi-purpose Regional Geochemical Survey Project, which classifies land quality based on soil nutrients (e.g., N, P, and K), harmful elements (e.g., As, Cd, Cr, Hg, and Pb), pH, and soil organic carbon content. This project also classifies land quality using indicators, such as air quality, irrigation water quality, and agricultural products safety, and accordingly evaluates land management. This study introduces the scale, unit, indicators, criteria, and grade classification of the evaluation system. Taking the geochemical evaluation of national land quality as an example, we introduce the results for soil nutrient, soil environment, and comprehensive geochemical classifications of land quality in the primary farming areas of China. The results indicate that the proportions of high quality and excellent soil are 47.5% and 38.1% of the total study area, respectively, which are widely distributed in the major grain-producing areas of China. These results can be widely applied for land use planning, improvement of land production potential, and for the prevention and control of endemic diseases. The geochemical evaluation of land quality in China is still in its infancy. Thus, the evaluation methods need further improvement. In addition, some problems arise in the integration of these methods with the existing agricultural land classification and grading systems in China. Many aspects of the current evaluation system, such as methods for obtaining and interpreting results, need to be improved to fully reflect the quality of cultivated land in China and to be in accordance with developed countries worldwide.
132143
Soil acidification in China: is controlling SO2 emissions enough?
Facing challenges of increased energy consumption and related regional air pollution, China has been aggressively implementing flue gas desulfurization (FGD) and phasing out small inefficient units in the power sector in order to achieve the national goal of 10% reduction in sulfur dioxide (SO(2)) emissions from 2005 to 2010. In this paper, the effect of these measures on soil acidification is explored. An integrated methodology is used, combining emission inventory data, emission forecasts, air quality modeling, and ecological sensitivities indicated by critical load. National emissions of SO(2), oxides of nitrogen (NO(X)), particulate matter (PM), and ammonia (NH(3)) in 2005 were estimated to be 30.7, 19.6, 31.3, and 16.6 Mt, respectively. Implementation of existing policy will lead to reductions in SO(2) and PM emissions, while those of NO(X) and NH(3) will continue to rise, even under tentatively proposed control measures. In 2005, the critical load for soil acidification caused by sulfur (S) deposition was exceeded in 28% of the country's territory, mainly in eastern and south-central China. The area in exceedance will decrease to 26% and 20% in 2010 and 2020, respectively, given implementation of current plans for emission reductions. However, the exceedance of the critical load for nitrogen (N, combining effects of eutrophication and acidification) will double from 2005 to 2020 due to increased NO(X) and NH(3) emissions. Combining the acidification effects of S and N, the benefits of SO(2) reductions during 2005-2010 will almost be negated by increased N emissions. Therefore abatement of N emissions (NO(X) and NH(3)) and deposition will be a major challenge to China, requiring policy development and technology investments. To mitigate acidification in the future, China needs a multipollutant control strategy that integrates measures to reduce S, N, and PM.
33273591
Haze in China: current and future challenges.
Regional haze which triggered both public anxiety and official concerns has been one of the most disastrous weather events in China in recent years. Haze not only had negative impact on daily life, but also an indicator of high concentrations of PM2.5 with the potential to adversely impact public health by damaging people's respiratory, cardiovascular, blood vessel of brain and nervous system. The dust-haze is an accumulated result for a long time of both natural factors and unhealthy economic growth model. In order to tackle air pollution, a number of policies and measures which target at reducing pollution emission and promoting alternative energy production had been implemented. Although significant improvement has occurred in China, change the development mode of "high growth, high pollution" and balance environmental conservation with the well-being of the population remains a challenge for China.
25209911
Geographic distribution patterns and status assessment of threatened plants in China
Large scale heterogeneous distribution of biodiversity has become a hot topic for ecologists and conservationists. A threat status assessment combined with geographic distribution patterns of threatened plants in China has been conducted at a national scale in this study based upon a distribution database that refers to both specimen records and published references. Currently, 302 threatened plant species are cataloged in the “National Protected Key Wild Plants” in China belonging to 92 families and 194 genera. Results of the assessment according to the Categories and Criteria system of The World Conservation Union (IUCN) Red List indicate that three species have been assessed as Extinct in Wild (EW) while a further 79, 99 and 112 species have been assessed as Critically Endangered (CR), Endangered (EN), and Vulnerable (VU), respectively. Distribution patterns of threatened plants were analyzed with GIS to identify areas of high species diversity. It was found that threatened plant species occur unevenly within counties and are concentrated in the following eight hotspots: the central and southern Hengduanshan mountain area; the southeast regions of Yunnan as well as Xishuangbanna and southwestern Guangxi; the southern Hainan island; the border mountainous regions of Guizhou, Hunan and Guangxi provinces; the mountainous regions of southwestern Hubei and northern Hunan; southwestern Zhejiang and western Fujian; central Sichuan and southern Gansu; and the western mountains of Guangdong. Moreover, the 12 counties with the greatest number of threatened plant species represent cumulatively more than 50% of the total listed species and, therefore, are the regions in China that should be prioritized for conservation efforts. By overlapping the map of threatened plant species with the distribution of national nature reserves, a gap was identified in protected areas. This research will ultimately provide insights for prioritizing biodiversity conservation as well as processing the mechanisms of distribution patterns.
15155150
Spatial-Temporal Dynamics of China's Terrestrial Biodiversity: A Dynamic Habitat Index Diagnostic
Biodiversity in China is analyzed based on the components of the Dynamic Habitat Index (DHI). First, observed field survey based spatial patterns of species richness including threatened species are presented to test their linear relationship with remote sensing based DHI (2001–2010 MODIS). Areas with a high cumulative DHI component are associated with relatively high species richness, and threatened species richness increases in regions with frequently varying levels of the cumulative DHI component. The analysis of geographical and statistical distributions yields the following results on interdependence, polarization and change detection: (1) The decadal mean Cumulative Annual Productivity (DHI-\(\overline{cum}\) 4) in Southeast China are in a stable (positive) relation to the Minimum Annual Apparent Cover (DHI-\(\overline{min}\)) and is positively (negatively) related to the Seasonal Variation of Greenness (DHI-\(\overline{sea}\)); (2) The decadal tendencies show bimodal frequency distributions aligned near DHI-\(\overline{min}\)~0.05 and DHI-\(\overline{sea}\)~0.5 which separated by zero slopes; that is, regions with both small DHI-min and DHI-sea are becoming smaller and vice versa; (3) The decadal tendencies identify regions of land-cover change (as revealed in previous research). That is, the relation of strong and significant tendencies of the three DHI components with climatic or anthropogenic induced changes provides useful information for conservation planning. These results suggest that the spatial-temporal dynamics of China’s terrestrial species and threatened species richness needs to be monitored by first and second moments of remote sensing based information of the DHI.
110984929
Research on Regional Ecological Security Assessment
Abstract [Purpose] This paper explains the basic theory and research methods of ecological security based on the basic concept of ecological security. Qinhuangdao City is the study area, the index system of its ecological security assessment was constructed on the basis of the pressure - state - response conceptual model, and its ecological security was evaluated by comprehensive index method. The evaluation result is that the ecological security index of Qinhuangdao is 0.633, and it is in the lower bound of the relatively safer state. At present, the main ecological problems are water shortage, water pollutions, large quantity of gaseous pollutants emission from heavy industry enterprises, inadequate protection of natural reserves, and insufficient investments in environmental protection. Some targeted countermeasures for strengthening regional ecological security management are proposed as following: establishing ecological security early warning system, developing and utilizing water resources rationally to improve water utilization efficiency, strengthening the marine environmental protection to ensure the security of marine environment, reducing sulfur dioxide emission volume by improving air quality through an effective way, and implementing ecological restoration project to improve the ecological carrying capacity. The ecology of Qinhuangdao would move to a safer ecological level through these channels.
18276830
Evaluation of the spatio-temporal pattern of urban ecological security using remote sensing and GIS
Research in urban ecology has recently focused on the field of ecological security. Ecological security should be assessed at different scales, from global (to understand some processes of global change) to regional (to understand processes in specific areas) to urban (to consider the processes of urban development). Remote sensing (RS) and geographical information systems (GISs) are widely utilized in ecological security evaluation, with remotely sensed images applied to determine the structure and quantitative indicators of urban ecological systems and GIS to manipulate, analyse, and visualize multisource information in urban ecology. This article focuses on urban ecological security assessment based on multitemporal RS information and GIS. As a case study, the changes in spatial patterns of urban ecological security in Xuzhou City are evaluated during its transformation from a coal mining industrial city to a modern one with decreasing mining production. The popular ‘pressure–state–response’ conceptual model is used to construct an evaluation framework according to geographical properties and data availability. A hierarchical weighted model is adopted to take different factors into account and determine the state of ecological security in the study area. Using Landsat Thematic Mapper/Enhanced Thematic Mapper Plus (TM/ETM+) images as the main RS data source, the derived parameters, such as vegetation index, urban thermal information, and landscape pattern, are integrated to depict the structure and properties of the urban ecological system. Other ancillary information, including mining pressure, water pollution pressure, population density, and ecological flexibility are collected and managed by ArcGIS. The GIS is then used to manage ecological factors derived from remotely sensed data, statistical reports, and geographical data, to evaluate and analyse urban ecological security, and to generate quantitative evaluation and spatial patterns of ecological security. The resulting maps of urban ecological security situations in 1987, 1994, 2000, 2005, and 2007 are analysed in both temporal and spatial dimensions. By analysing urban ecological security in both temporal and spatial dimensions, it is concluded that the ecological security of Xuzhou City is under increasing pressure. Influenced by the pressure of urbanization and mining industry development, the unsafe areas of Xuzhou City have greatly expanded, and with accelerating speed. Finally, suggestions for improving urban ecological security are provided.
145760228
Crisis theory/practice: towards a sustainable future
We are living in a world rife with many types of crises. The most prominent and urgent crises involve the earth's ecology. Environmental crises involving Ozone depletion, global warming, toxic and radioactive wastes, air pollution, industrial accidents etc. are affecting communities around the world. In this paper, I examine changes in crisis management theory and practice. In the past two decades, much progress has been made in our understanding of industrial and environmental crises. However, our understanding remains highly fragmented and selective. We need to integrate diverse findings and cumulatively build on past knowledge. To do this the concept of "sustainable development" provides a unifying motif. Some research questions that deserve urgent attention are identified.
205049746
A safe operating space for humanity
Identifying and quantifying planetary boundaries that must not be transgressed could help prevent human activities from causing unacceptable environmental change, argue Johan Rockstrom and colleagues.
60812681
Modeling Sensitivity to Accuracy in Classified Imagery: A Study of Areal Interpolation by Dasymetric Mapping*
Areal interpolation is the process by which data collected from one set of zonal units can be estimated for another zonal division of the same space that shares few or no boundaries with the first. In previous research, we outlined the use of dasymetric mapping for areal interpolation and showed it to be the most accurate method tested. There we used control information derived from classified satellite imagery to parameterize the dasymetric method, but because such data are rife with errors, here we extend the work to examine the sensitivity of the population estimates to error in the classified imagery. Results show the population estimates by dasymetric mapping to be largely insensitive to the errors of classification in the Landsat image when compared with the other methods tested. The dasymetric method deteriorates to the accuracy of the next worst estimate only when 40% error occurs in the classified image, a level of error that may easily be bettered within most remote sensing projects.
29665980
A Reconstruction of Regional and Global Temperature for the Past 11,300 Years
Exceptional Now The climate has been warming since the industrial revolution, but how warm is climate now compared with the rest of the Holocene? Marcott et al. (p. 1198) constructed a record of global mean surface temperature for more than the last 11,000 years, using a variety of land- and marine-based proxy data from all around the world. The pattern of temperatures shows a rise as the world emerged from the last deglaciation, warm conditions until the middle of the Holocene, and a cooling trend over the next 5000 years that culminated around 200 years ago in the Little Ice Age. Temperatures have risen steadily since then, leaving us now with a global temperature higher than those during 90% of the entire Holocene. Current global average surface air temperature is warmer than that for all but a small fraction of the past 11,300 years. Surface temperature reconstructions of the past 1500 years suggest that recent warming is unprecedented in that time. Here we provide a broader perspective by reconstructing regional and global temperature anomalies for the past 11,300 years from 73 globally distributed records. Early Holocene (10,000 to 5000 years ago) warmth is followed by ~0.7°C cooling through the middle to late Holocene (<5000 years ago), culminating in the coolest temperatures of the Holocene during the Little Ice Age, about 200 years ago. This cooling is largely associated with ~2°C change in the North Atlantic. Current global temperatures of the past decade have not yet exceeded peak interglacial values but are warmer than during ~75% of the Holocene temperature history. Intergovernmental Panel on Climate Change model projections for 2100 exceed the full distribution of Holocene temperature under all plausible greenhouse gas emission scenarios.
8487558
China's environment in a globalizing world
How China and the rest of the world affect each other.China's place in the worldChina's environmental problems dominate those of the world, not only because China contains a fifth of the world's people, but also because China's economy is so big and developing so rapidly. The expanding links of globalization mean that China's problems are the world's problems too. In a Feature this week, Jianguo Liu and Jared Diamond look at the effects of China's sweeping environmental change and socio-economic challenges, synthesizing detailed literature that is scattered even for Chinese readers and largely inaccessible to western readers. On the cover, crowds on Nanjing Lu, Shanghai's famous shopping street where global influences are clear to see (Mark Henley/Panos). Elsewhere in the issue, Peter Aldhous reports on how China plans to cope with its exploding need for energy.
9665006
Transform Coefficient Histogram-Based Image Enhancement Algorithms Using Contrast Entropy
Many applications of histograms for the purposes of image processing are well known. However, applying this process to the transform domain by way of a transform coefficient histogram has not yet been fully explored. This paper proposes three methods of image enhancement: a) logarithmic transform histogram matching, b) logarithmic transform histogram shifting, and c) logarithmic transform histogram shaping using Gaussian distributions. They are based on the properties of the logarithmic transform domain histogram and histogram equalization. The presented algorithms use the fact that the relationship between stimulus and perception is logarithmic and afford a marriage between enhancement qualities and computational efficiency. A human visual system-based quantitative measurement of image contrast improvement is also defined. This helps choose the best parameters and transform for each enhancement. A number of experimental results are presented to illustrate the performance of the proposed algorithms
84924448
Implications of Liebig's law of the minimum for the use of ecological indicators based on abundance
Many ecological responses to environmental variables or anthropogenic agents are difficult and expensive to measure. Therefore it is attractive to describe such responses in terms of indicators that are easier to measure. In ecosystem management, indicators can be used to monitor spatial and temporal changes in an environmental feature. The aim of this paper is to show that it is important to take Liebig's law of the minimum into consideration to understand when it is appropriate or inappropriate to use ecological indicators based on abundance. When developing indicators that relate the abundance of an organism to an environmental factor, it is likely that this relationship will be polygonal rather than a simple linear relationship. The upper boundary of the distribution describes how abundance is limited by this factor, while the variation below the upper boundary is explained by situations when factors other than the factor of interest limit abundance. The variation below the upper boundary of the distribution means that the use of indicators to examine spatial patterns in the response of abundance to an environmental factor can be problematic. Thus, while abundance-based indicators can identify sites that are in a good condition, they are less useful to detect those affected by environmental degradation. In contrast, abundance-based ecological indicators may enable temporal monitoring of the impact of environmental factors, as it is expected that limiting factors are less variable in time than in space. In conclusion, when multiple factors are limiting, a significant correlation between an indicator and a variable is not enough to validate the status of a factor as an indicator.