West Nile virus in American crows (Corvus brachyrhynchos) in Canada: projecting the influence of climate change

The present study examined the influence of climate change on the spread of West Nile virus (WNV) in Canada among American crows (Corvus brachyrhynchos) by first identifying the significant climatic and environmental determinants of positive WNV cases in American crow specimens from 2009 to 2013. Using this information, we projected climate change scenarios on the potential spread of WNV in American crow species in Canada for three time periods: 2015–2039, 2040–2069, and 2070–2099. Using bird specimen, meteorological and land-use data, the statistical association between positive WNV cases in American crows and the environment was assessed by means of a general linear mixed model. Statistical results revealed that temperature and precipitation were significantly related to positive cases of WNV in American crows. Thus, climate change projections of summer mean temperature averages were projected for the three time periods. Climate change scenarios were created and imported into Quantum Geographic Information System (QGIS) and an algorithm was applied using the raster calculator to spatially delineate current and future areas of risk. Spatial analyses revealed that increased warming in the near future may increase the latitudinal extension of WNV in American crows in Canada.     

A spatially explicit degree-day model of Rift Valley fever transmission risk in the continental United States

A spatially explicit degree-day model was used to evaluate the risk of Rift Valley fever virus (RVFV) transmission by mosquitoes to humans and livestock within five target states in the continental United States: California, Minnesota, Nebraska, New York, and Texas. A geographic information system was used to model potential virus transmission based on a 12-day moving window assessment of the extrinsic incubation period theorized for RVFV in the United States. Risk of potential virus transmission in each state was spatially evaluated on a 10-km grid using average historical daily temperature data from 1994 to 2003. The highest levels of transmission risk occur in California and Texas, with parts of these states at risk of RVFV transmission for up to 8 months per year. Northern Minnesota, central New York, and most of coastal and high-elevation California are at low to null risk. Risk of impact to the livestock industry is greatest in California, Texas, and Nebraska. A standard global climate model was used to evaluate future risk in the year 2030 in Nebraska, and showed an increase of transmission risk days from approximately 3 to 4 months per year.     

度日模型在冰川与积雪研究中的应用进展

度日模型是基于冰川与积雪消融和气温,尤其是冰雪表面的正积温之间的线性关系建立的.度日模型已广泛应用于北欧、阿尔卑斯山、格陵兰冰盖、青藏高原等地区的冰雪消融、冰川物质平衡及对气候敏感性响应、冰川动力模型以及冰雪融水径流模拟等的研究中.度日模型尽管是对冰雪表面消融能量平衡这一复杂过程的简化描述,但在流域尺度上,通常可以获取类似于能量平衡模型的输出结果.度日模型也有其不足之处,仍需进一步的改进与完善.     

Research on quantitative assessment of climate change risk at an urban scale: Review of recent progress and outlook of future direction

Cities are not only major contributors to global climate change but also stand at the forefront of climate change impact. Quantifying and assessing the risk potentially induced by climate change has great significance for cities to undertake positive climate adaptation and risk prevention. However, most of the previous studies focus on global, national or regional dimensions, only a few have attempted to examine climate change risk at an urban scale and even less in the case of a recent literature review. As a result, a quantitative assessment of climate change risk for cities remains highly challenging. To fill this gap, the article makes a critical review of the recent literature on urban-scale climate change risk assessment, and classifies them into four major categories of studies which jointly constitute a stepwise modelling chain from global climate change towards urban-scale risk assessment. On this basis, the study summarizes the updated research progresses and discusses the major challenges to be overcome for the seamless coupling of climate simulation between different scales, the reproduction of compound climate events, the incorporation of non-market and long-lasting impacts and the representation of risk transmission insides or beyond a city. Furthermore, future directions to advance quantitative assessment of urban-scale climate change risk are highlighted, with fresh insights into improving study methodology, enriching knowledge of climate change impact on city, enhancing abundance and accessibility to data, and exploring the best practice to provide city-specific climate risk service.     

Research on quantitative assessment of climate change risk at an urban scale: Review of recent progress and outlook of future direction

Cities are not only major contributors to global climate change but also stand at the forefront of climate change impact. Quantifying and assessing the risk potentially induced by climate change has great significance for cities to undertake positive climate adaptation and risk prevention. However, most of the previous studies focus on global, national or regional dimensions, only a few have attempted to examine climate change risk at an urban scale and even less in the case of a recent literature review. As a result, a quantitative assessment of climate change risk for cities remains highly challenging. To fill this gap, the article makes a critical review of the recent literature on urban-scale climate change risk assessment, and classifies them into four major categories of studies which jointly constitute a stepwise modelling chain from global climate change towards urban-scale risk assessment. On this basis, the study summarizes the updated research progresses and discusses the major challenges to be overcome for the seamless coupling of climate simulation between different scales, the reproduction of compound climate events, the incorporation of non-market and long-lasting impacts and the representation of risk transmission insides or beyond a city. Furthermore, future directions to advance quantitative assessment of urban-scale climate change risk are highlighted, with fresh insights into improving study methodology, enriching knowledge of climate change impact on city, enhancing abundance and accessibility to data, and exploring the best practice to provide city-specific climate risk service.     

Research on quantitative assessment of climate change risk at an urban scale: Review of recent progress and outlook of future direction

Cities are not only major contributors to global climate change but also stand at the forefront of climate change impact. Quantifying and assessing the risk potentially induced by climate change has great significance for cities to undertake positive climate adaptation and risk prevention. However, most of the previous studies focus on global, national or regional dimensions, only a few have attempted to examine climate change risk at an urban scale and even less in the case of a recent literature review. As a result, a quantitative assessment of climate change risk for cities remains highly challenging. To fill this gap, the article makes a critical review of the recent literature on urban-scale climate change risk assessment, and classifies them into four major categories of studies which jointly constitute a stepwise modelling chain from global climate change towards urban-scale risk assessment. On this basis, the study summarizes the updated research progresses and discusses the major challenges to be overcome for the seamless coupling of climate simulation between different scales, the reproduction of compound climate events, the incorporation of non-market and long-lasting impacts and the representation of risk transmission insides or beyond a city. Furthermore, future directions to advance quantitative assessment of urban-scale climate change risk are highlighted, with fresh insights into improving study methodology, enriching knowledge of climate change impact on city, enhancing abundance and accessibility to data, and exploring the best practice to provide city-specific climate risk service.     

Shallow landslide susceptibility assessment under future climate and land cover changes: A case study from southwest China

There is no doubt that land cover and climate changes have consequences on landslide activity, but it is still an open issue to assess and quantify their impacts. Wanzhou County in southwest China was selected as the test area to study rainfall-induced shallow landslide susceptibility under the future changes of land use and land cover (LULC) and climate. We used a high-resolution meteorological precipitation dataset and frequency distribution model to analyse the present extreme and antecedent rainfall conditions related to landslide activity. The future climate change factors were obtained from a 4-member multi-model ensemble that was derived from statistically downscaled regional climate simulations. The future LULC maps were simulated by the land change modeller (LCM) integrated into IDRISI Selva software. A total of six scenarios were defined by considering the rainfall (antecedent conditions and extreme events) and LULC changes towards two time periods (mid and late XXI century). A physically-based model was used to assess landslide susceptibility under these different scenarios. The results showed that the magnitude of both antecedent effective recharge and event rainfall in the region will evidently increase in the future. Under the scenario with a return period of 100 years, the antecedent rainfall in summer will increase by up to 63% whereas the event rainfall will increase by up to 54% for the late 21st century. The most considerable changes of LULC will be the increase of forest cover and the decrease of farming land. The magnitude of this change can reach + 22.1% (forest) and –9.2% (farmland) from 2010 until 2100, respectively. We found that the negative impact of climate change on landslide susceptibility is greater than the stabilizing effect of LULC change, leading to an over decrease in stability over the study area. This is one of the first studies across Asia to assess and quantify changes of regional landslide susceptibility under scenarios driven by LULC and climate change. Our results aim to guide land use planning and climate change mitigation considerations to reduce landslide risk.     

Climate change impacts on U.S. Coastal and Marine Ecosystems

Increases in concentrations of greenhouse gases projected for the 21st century are expected to lead to increased mean global air and ocean temperatures. The National Assessment of Potential Consequences of Climate Variability and Change (NAST 2001) was based on a series of regional and sector assessments. This paper is a summary of the coastal and marine resources sector review of potential impacts on shorelines, estuaries, coastal wetlands, coral reefs, and ocean margin ecosystems. The assessment considered the impacts of several key drivers of climate change: sea level change; alterations in precipitation patterns and subsequent delivery of freshwater, nutrients, and sediment; increased ocean temperature; alterations in circulation patterns; changes in frequency and intensity of coastal storms; and increased levels of atmospheric CO₂. Increasing rates of sea-level rise and intensity and frequency of coastal storms and hurricanes over the next decades will increase threats to shorelines, wetlands, and coastal development. Estuarine productivity will change in response to alteration in the timing and amount of freshwater, nutrients, and sediment delivery. Higher water temperatures and changes in freshwater delivery will alter estuarine stratification, residence time, and eutrophication. Increased ocean temperatures are expected to increase coral bleaching and higher CO₂ levels may reduce coral calcification, making it more difficult for corals to recover from other disturbances, and inhibiting poleward shifts. Ocean warming is expected to cause poleward shifts in the ranges of many other organisms, including commercial species, and these shifts may have secondary effects on their predators and prey. Although these potential impacts of climate change and variability will vary from system to system, it is important to recognize that they will be superimposed upon, and in many cases intensify, other ecosystem stresses (pollution, harvesting, habitat destruction, invasive species, land and resource use, extreme natural events), which may lead to more significant consequences.     

Impacts of climate change on flow regime and sequential threats to riverine ecosystem in the source region of the Yellow River

Climate change is expected to have substantial impacts on flow regime in the Upper Yellow River (UYR) basin that is one of the most important biodiversity hotspots in the world. These impacts will most possibly exert negative effects on the habitat availability for riverine species. Thus, it is necessary to understand the alteration of river flow regime under climate scenarios. In this paper, we use the modified hydrological model HBV in conjunction with three general circulation models under three representative concentration pathways (RCP 2.6, 4.5, and 8.5) to address changes in flow regime under climate change for the UYR basin in the mid-term (2050s) and end-term (2080s) of the twenty-first century. Flow regime is quantified using the Indicators of hydrological alteration approach. Thereafter, the potential threats to riverine ecosystem in the UYR basin are identified based on the projected alterations of various flow characteristics and their ecological influences. The results showed that the magnitude of monthly flow would increase during the dry period. The date of the annual 1-day minimum streamflow will likely shift toward earlier time under different scenarios, and significant increases in magnitude of annual minimum flow of different durations were detected under both RCP 4.5 and 8.5 scenarios in the 2080s. In addition, assessments of the modification degree of the overall flow regime revealed that climate change would remarkably modify (medium level) the overall flow regime in the UYR basin, particularly by the end of the twenty-first century or under the high emission scenarios. Besides, destruction of habitat and reduced availability of food induced by substantially increased hydrological instability in the 2080s would make two endangered fishes more vulnerable in the UYR basin. These findings provide insights into potential adaptive countermeasures for water resource management and environmental system restoration in the Upper Yellow River.     

Tools for assessing the impact of climate change on freshwater fish populations

We identify and discuss ways to use existing information on the thermal ecology of freshwater fishes to assess the potential impact of climate change on wild populations of these organisms. Two primary questions are identified: (i) how do aquatic habitats change in response to atmospheric climate change? (ii) how do fish respond to habitat change at both the individual and population levels? In lakes, climate warming will lead to higher surface water temperatures, longer ice-free periods, and longer periods of thermal stratification. In rivers, climate warming will lead to higher groundwater temperatures with corresponding increases in both summer and winter temperatures, from headwaters to mouth. We describe several methods for predicting the biological effects of these changes in habitat. We examine the use of bioenergetic models to predict the impact of climate change on the growth of individual fish. We examine the use of thermal habitat models to assess the impact of climate change on population abundance. We examine the use of life cycle models to assess the impact of climate change on the zoogeographic distribution of species. Finally, we identify new research required to further develop these methods.     

Modeling the Effects of Future Outflow on the Abiotic Habitat of an Imperiled Estuarine Fish

Future development and climate change pose potentially serious threats to estuarine fish populations around the world. We examined how habitat suitability for delta smelt (Hypomesus transpacificus), a state and federally protected species, might be affected by changes in outflow in the San Francisco Estuary due to future development and climate change. Forty years of sampling data collected during fall from 1967 to 2008 were examined to define abiotic habitat suitability for delta smelt as a function of salinity and water transparency, and to describe long-term trends in habitat conditions. The annual habitat index we developed, which incorporated both quantity and quality of habitat, decreased by 78% over the study period. Future habitat index values under seven different development and climate change scenarios, representing a range of drier and wetter possibilities, were predicted using a model which related estuarine outflow to the habitat index. The results suggested that each of the scenarios would generally lead to further declines in delta smelt habitat across all water year types. Recovery targets for delta smelt will be difficult to attain if the modeled habitat conditions are realized.     

Climate change and its impacts on the coastal zone of the Nile Delta,Egypt

The main objectives of the current work are (1) to determine historic pattern of shoreline changes (erosion and accretion) along the north coast of the Nile Delta, (2) to present a future view on what to be expected regarding climate change impacts, sea-level rise (SLR) scenarios, expected land losses and alteration of some soil characteristics (3) to recognize negative impacts of SLR on the Nile Delta coast and (4) to assess and suggest protection measures. The current investigation was conducted using the advanced techniques of remote sensing and geographic information system. The investigated area with 394 measured locations is located along the northern coast of the Nile Delta between Alexandria and ElTina plain in Sinai peninsula exactly between 29°20′ and 32°40′ E and 29°54′ and 31°35′ N with the minimum erosion values of 1.11 m², maximum of 6,044,951.64 m² and total of 16.02 km². On the other hand, 177 sites showed minimum accretion values of 0.05 m², maximum of 2,876,855.86 m² and total of 13.19 km². SLR was determined by applying the quadrant equation for 10-year intervals using 1990 as the base year. Mediterranean SLR along the Nile Delta coast could be estimated considering three different scenarios (low 0.20 m, medium 0.50 m, and high 0.90 m). Impacts of SLR are divided into (1) primary and (2) secondary impacts. Over the coming decades, the Nile Delta will face greater threat due to SLR and land subsidence as well. Regarding climate change and its impacts on soil characteristics, rapid increase in salinity values during the former three decades were found. This increase may be due to the intrusion of salty water of the Mediterranean. On the other hand, organic matter content decreased due to higher temperature, especially during the summer season. Some protection measures were assessed and suggested to combat or tackle SLR.     

中国历史时期气候变化对社会发展的影响*

历史时期气候变化对社会发展的影响与人类适应问题,是当前全球变化领域的研究热点之一。近年来,在利用丰富的历史文献资料研究中国历史时期(特别是过去2000年时段)气候变化与人类社会相互作用的过程机理方面取得了一系列新成果。本文将其归纳为3个方面: 理论上,构建了基于粮食安全的气候影响传递过程分析框架;方法上,实现了服务于气候变化影响研究的、基于语义差异的历史社会经济序列定量重建;科学认识上,总结出“冷抑暖扬”而又福祸相依的宏观韵律。在此基础上,对未来研究需要进一步深化的方向进行了展望。     

Impact of water demand on hydrological regime under climate and LULC change scenarios

The present study focuses on an assessment of the impact of future water demand on the hydrological regime under land use/land cover (LULC) and climate change scenarios. The impact has been quantified in terms of streamflow and groundwater recharge in the Gandherswari River basin, West Bengal, India. dynamic conversion of land use and its effects (Dyna-CLUE) and statistical downscaling model (SDSM) are used for quantifying the future LULC and climate change scenarios, respectively. Physical-based semi-distributed model Soil and Water Assessment Tool (SWAT) is used for estimating future streamflow and spatiotemporally distributed groundwater recharge. Model calibration and validation have been performed using discharge data (1990–2016). The impacts of LULC and climate change on hydrological variables are evaluated with three scenarios (for the years 2030, 2050 and 2080). Temperature Vegetation Dyrness Index (TVDI) and evapotranspiration (ET) are considered for estimation of water-deficit conditions in the river basin. Exceedance probability and recurrence interval representation are considered for uncertainty analysis. The results show increased discharge in case of monsoon season and decreased discharge in case of the non-monsoon season for the years 2030 and 2050. However, a reverse trend is obtained for the year 2080. The overall increase in groundwater recharge is visible for all the years. This analysis provides valuable information for the irrigation water management framework.     

The Green Bay ecosystem and assessment of climate change impacts

Climate change will have major impacts in the Great Lakes region of North America. Particularly vulnerable are shallow freshwater estuaries, such as Lake Michigan’s Green Bay, located in the north-eastern part of the State of Wisconsin. Green Bay and the Lower Fox River, its major tributary, were considered to be severely polluted as early as 1925. As a result of large expenditures of money and a major research effort that has been conducted over the past 40 years or more, some progress has been made toward the restoration of ecosystem integrity. However, work remains, and within this context, potential climate change impacts pose additional challenges. We discuss in this paper a methodology that can be used to assess climate change impacts on ecosystems, and describe an application to the Green Bay ecosystem. The methodology employs numerical methods to evaluate the inputs from scientific, policy, and management experts who are knowledgeable about the ecosystem under study. The Green Bay ecosystem application reveals that runoff from agriculture and urban sources, already a major ecosystem stressor, will be exacerbated in the future as a result of climate change impacts.     

A Study of Global Change Population and Economic System Risk Forming Mechanism and Assessment

Global climate change featured with warming has created serious challenge to world sustainable development and human security. It has become an important consensus of the international society to assess global change risk at the global scale and carry out tailored governance and risk-based adaptation. National Key Research and Development Program “Study on global change population and economic system risk forming mechanism and assessment” aims at quantitatively predicting future global climate change and population and economic system exposure and vulnerability change, developing global change population and economic system risk assessment model based on complex system dynamics, synthesizing risk assessment model with proprietary intellectual property rights, assess global change population and economic system risk of the near and mid future at the global scale, and compiling the atlas of global change population and economic system risk. The outcomes intend to serve the participation of global risk governance and international climate negotiation, and to provide scientific support to the implementation of international disaster risk reduction strategy.     

中国西部生态环境变化与对策建议

中国西部地区生态环境的历史演变过程与未来可能变化趋势是科学界面对的一大难题,正确认识西部地区生态环境的演变过程与变化趋势,是西部地区社会经济可持续发展必须面对的课题,是正确制定西部大开发战略方针的重要科学基础。依托中国科学院牵头完成的《中国西部环境演变评估》研究成果,介绍了中国西部地区生态环境演变的主要特征与基本事实,主要强调近50年来全球变暖与人类活动在西部生态环境演变中的重要作用;指出未来的气候与环境变化对西部地区的经济社会发展将产生重要影响;提出了西部地区生态保护与可持续发展的对策与建议,指出西部地区的生态建设必须综合治理、突出重点,特别强调要强化对西部地区的科学研究,为西部大开发服务。     

全球气候变化对湿地生态水文的影响研究综述

近百年来全球气候呈现以变暖为主要特征的显著变化,并且未来气温将继续上升,降水模式也会发生改变。从气候变化对湿地水文水资源的影响、气候变化影响下湿地水文与生态的相互作用过程以及湿地生态水文模型等3个方面,对国内外相关研究动态和发展趋势进行了总结分析。从中发现,当前全球气候背景下的湿地生态水文学正在从单一湿地生态水文过程为主要对象,发展成为以研究气候-水文-生态三者相互作用机制为主要内容的综合性、交叉性学科。现关于气候变化影响下水文-生态之间的关系多集中于单向作用的研究,特别是水文过程对植被的影响研究较多,缺乏对气候变化影响下湿地水文过程与生态过程相互作用机理的全面认识。气候变化对湿地生态水文的影响机制研究已经成为水文学研究亟待解决的科学问题,而基于物理机制的湿地生态水文模型,逐渐成为预测未来气候变化下湿地生态水文响应的重要工具。     

未来不同气候变化情景下我国玉米产量的初步预测

玉米是我国重要的粮食和饲料作物,研究气候变化对我国玉米产量的影响有重要意义。采用区域气候模式与CERES Maize模型相结合的方法,模拟了基准气候（BS,1961—1990年）和A2、B2两种温室气体排放方案下2011—2100年我国雨养和灌溉玉米产量,初步预测了未来不同气候情景下玉米产量的变化状况。结果表明,如果保持现有的玉米生产状况,气候变化将导致我国玉米主产区的玉米单产普遍降低,总产下降,给玉米生产带来一定经济损失。A2气候变化情景对我国玉米产量的负面影响要大于B2情景。CO2肥效作用可以在一定程度上缓解这种负面影响,其缓解作用对雨养玉米更明显。未来全国玉米主产区的雨养和灌溉玉米的稳产风险及低产出现的概率将会增大,总产的年际波动更剧烈。由于目前研究结果是未考虑农业生产的适应措施而得出的,可能会高估气候变化的负面影响。     

Application of Species Distribution Models to Identify Estuarine Hot Spots for Juvenile Nekton

Modeling the distribution and habitat capacities of key estuarine species can be used to identify hot spots, areas where species density is significantly higher than surrounding areas. This approach would be useful for establishing a baseline for evaluating future environmental scenarios across a landscape. We developed species distribution models for early juvenile life stages of brown shrimp (Farfantepenaeus aztecus), white shrimp (Litopenaeus setiferus), blue crab (Callinectes sapidus), and spotted seatrout (Cynoscion nebulosus) in order to delineate the current coastal hot spots that provide the highest quality habitat conditions for these estuarine-dependent species in Louisiana. Response curves were developed from existing long-term fisheries-independent monitoring data to identify habitat suitability for fragmented marsh landscapes. Response curves were then integrated with spatially explicit input data to generate species distribution models for the coastal region of Louisiana. Using spatial autocorrelation metrics, we detected clusters of suitable habitat across the Louisiana coast, but only 1% of the areas were identified as true hot spots with the highest habitat quality for nekton. The regions identified as hot spots were productive fringing marsh habitats that are considered the most vulnerable to natural and anthropogenic impacts. The species distribution models identify the coastal habitats which currently provide the greatest capacity for key estuarine species and will be used in the Louisiana coastal planning process to evaluate how species distributions may change under various environmental and restoration scenarios.