气候变化对中国水安全的影响研究

全球变暖是目前最重要的环境问题之一,水是全球气候变化最直接和最重要的影响领域。全球气候变暖将加速大气环流和水文循环过程,引起水资源量及其空间分布的变化,进而可能导致水资源短缺问题更加突出、水生态环境问题进一步恶化、洪涝灾害威胁更加严重等一系列问题。本文从防洪安全、供水安全、水生态环境安全和水工程安全4个方面分别阐述气候变化对中国水安全的可能影响。     

气候变化对中国水安全的影响研究

 全球变暖是目前最重要的环境问题之一,水是全球气候变化最直接和最重要的影响领域。全球气候变暖将加速大气环流和水文循环过程,引起水资源量及其空间分布的变化,进而可能导致水资源短缺问题更加突出、水生态环境问题进一步恶化、洪涝灾害威胁更加严重等一系列问题。本文从防洪安全、供水安全、水生态环境安全和水工程安全4个方面分别阐述气候变化对中国水安全的可能影响。     

甘肃气象灾害与气候变化问题的初步研究

根据气象资料和社会经济资料,分析了甘肃省气象灾害特征及其对甘肃社会经济的影响,揭示了近50 a年甘肃气候变化的客观事实,探讨了在气候变暖背景下甘肃自然生态系统的变化。针对甘肃社会经济可持续发展中的气象与生态问题,提出了适应对策。     

突泉县生态环境与气候变化

通过对突泉县近50a来气候变化对农牧业的影响,阐述了气候变暖对突泉县生态环境的影响,提出了生态环境防治对策。     

新疆气候变化与生态环境的初步评估

近50a来,新疆气候变暖、降水增多的趋势明显,并将持续到21世纪末.新疆生态环境系统的总体特征是:水资源是新疆生态环境的核心;形成了山地、绿洲、荒漠三大生态环境系统;生态环境脆弱;土地有效利用率低;加强生态建设和环境保护具有很大潜力.在全球和新疆气候变暖的背景下,新疆极端天气、气候事件频发,防灾减灾形势更为严峻,而且绝大部分冰川退缩,并呈加速减退的趋势;但因气候变暖的同时降水增多,河流径流量呈增加趋势,生态环境随之有所恢复与改善,加之新疆又地处欧亚大陆中部,因而全球气候变化造成直接的、近期的负面影响,在新疆的表现比世界大多数地区要轻、要小.由于新疆气候变化、人类活动的负面影响以及资源利用效率低下、经济结构不合理等因素,新疆生态环境形势依然相当严峻,完全遏制生态环境恶化和实现生态环境全面改善任重道远.基于以上评估结论,提出了三项对策建议.     

西北地区气候变化新动态及对干旱环境的影响——总体暖干化,局部出现暖湿迹象

近50 a来,西北地区气温呈显著的上升趋势,降水变化空间差异突出,西北地区整体暖干化趋势明显,局部出现暖湿现象。气候变暖使冰川退缩,雪线上升,冻土消融,湿地退化,湖泊萎缩,河流流量减少,水资源越来越短缺,出现生态环境恶化问题。根据IPCC预测结果分析,未来西北地区气候变暖趋势会更加明显。从保护西北地区生态环境、完善气候变化综合监测系统以及开展重点区域气候变化过程专项研究等方面提出了对策建议。     

通辽市的气候变化与生态环境

从通辽市近50年来气候变化及其对农牧林业、水资源、土地沙化、草场退化等方面的影响,阐述了气候变暖给通辽市生态环境带来的影响,提出了生态环境防治对策。     

气候变暖对内蒙古生态环境的影响

从内蒙古近50年来气候变化及其对农牧业、水资源、土地沙化、草场退化等方面阐述了气候变暖给内蒙古生态环境带来的影响，提出了生态环境防治对策。     

黄河源区域生态环境演变与对策建议

黄河源区是三江源自然保护区的重要组成部分,在全球气候变暖和日趋频繁的人类活动的共同影响下,黄河源区的生态结构受到严重干扰。通过对黄河源区域生态与自然环境演变特征研究进展的概括总结,从生态系统和物理环境2个方面归纳了黄河源区主要的生态环境问题：（1）植被、冻土和湿地生态系统不断退化;（2）气候暖干化、径流变化、土壤侵蚀、土壤沙漠化、土壤碳流失、鼠害和人为影响加剧。根据面临的生态环境问题提出了区域生态与自然环境保护的相应对策和建议：形成完善的生态补偿机制;加强生态环境保护立法;建立统一的监督管理机构;建立有效的执法队伍;划分功能区;发展生态旅游;强化全社会的环保意识。     

气候变化与武汉城市圈可持续发展

针对湖北省加速发展实现中部崛起和武汉构筑并发展城市圈的目标,从全球气候变暖的背景出发,结合近50年多来武汉气候变化的事实,揭示了该市气候变化特征,并从发展经济与防灾减灾、应对气候变化与改善气候生态环境、淡化武汉“火炉”形象与发展“高温经济”等方面提出了相应对策.     

Nonmarket Valuation and the Estimation of Damages from Global Warming

This paper is concerned with nonmarket valuation in the context of global warming. First, concerning the impact of global warming: what are the prospects for the inclusion of nonmarket values in estimates of the damages of warming? The second question relates to the role of the Principles and Guidelines as the supporting document for water resource projects. Are tools for nonmarket valuation, as found in the Principles and Guidelines satisfactory for water resource project evaluation with a changing climate? The potential effects of climate change are so numerous and subtle that it would be prohibitively costly to measure them all. Thus a comprehensive program for including nonmarket damages as part of the costs of global warming seems ill-advised. Where specific concerns arise, researchers may learn from small scale studies. Many of the damages of global warming are diminished by the ability of humans to adapt at small costs, especially the nonuse component of nonmarket values. When the question concerns minor water resource projects, the gains from including extra effects induced by global warming seem to be small compared with the costs. The Principles and Guidelines does not reflect current practices in benefit estimation. However, it is not clear that this is a serious problem, because most practitioners continue to revise their understanding of valuation methods. If the Principles and Guidelines were to be revised, it would make sense to provide more current guidelines for all of the behavioral models and contingent valuation. Revisions of the Principles and Guidelines should not do anything special for anthropocentrically induced climate change.     

Future African Water Resources: Interactions between Soil Degradation and Global Warming

This study uses a well-established water balance methodology to evaluate the relative impact of global warming and soil degradation due to desertification on future African water resources. Using a baseline climatology, a GCM global warming scenario, a newly derived soil water-holding capacity data set, and a worldwide survey of soil degradation between 1950 and 1980, four climate and soil degradation scenarios are created to simulate the potential impact of global warming and soil degradation on African water resources for the 2010–2039 time period. Results indicate that, on a continental scale, the impact of global warming will be significantly greater than the impact of soil degradation. However, when only considering the locations where desertification is an issue (wet and dry climate regions), the potential effects of these two different human impacts on local water resources can be expected to be on the same order of magnitude. Drying associated with global warming is primarily the result of increased water demand (potential evapotranspiration) across the entire continent. While there are small increases in precipitation under global warming conditions, they are inadequate to meet the increased water demand. Soil degradation is most severe in highly populated, wet and dry climate regions and results in decreased water-holding capacities in these locations. This results in increased water surplus conditions during wet seasons when the soil's ability to absorb precipitation is reduced. At the same time, water deficits in these locations increase because of reduced soil water availability in the dry seasons. The net result of the combined scenarios is an intensification and extension of drought conditions during dry seasons.     

全球变暖趋缓背景下辽宁夏季降水变化及水汽输送特征

利用中国气象数据网提供的中国地面气候资料日值数据集（V3.0）中的降水数据以及ERA-Interim逐月再分析资料对全球变暖趋缓背景下（1998年后）辽宁夏季降水变化特征及水汽输送对其的影响进行研究。结果表明：全球增暖减缓背景下,辽宁夏季降水量存在一定的增加趋势,但趋势较弱,其中辽宁南部降水的增加趋势较其他地区显著,对辽宁整体降水变化的贡献程度相对较高。辽宁南北边界的夏季水汽通量与降水量呈现高度的正相关性。其中,南边界的相关性程度最显著。辽宁上空纬向水汽净输入量对降水的贡献较小,经向水汽通量对于降水的贡献较纬向高且其高值区主要位于辽宁东部及南部地区的对流层低层,对当地降水存在影响。辽宁南部对流层整层的经向水汽通量与辽宁降水量存在显著正相关,通过分析大气环流背景场的变化对辽宁经向水汽输送的影响分析,西太平洋副热带高压脊线的逐渐北移是造成辽宁经向水汽通量增加的重要因素,从而直接影响辽宁降水量的变化趋势,导致辽宁夏季降水在全球变暖减缓背景下存在一定的增加趋势。     

陆表自然和人文要素相互作用——“全球变化及应对”重点专项研究进展

在国家重点研发计划支持下,项目提出了陆表不均一性检测和订正的新方法,解决了渐变型不均一性检测和订正的难题,构建了中国地表太阳辐射、气温、地温、风速和降水等参数均一化站点和格点数据集,修订了关于中国地表风速变化趋势、增温格局及其形成机制的结论。融合多源数据,构建并验证了千米级、流域级或县域级的电厂、人口、生物质能、取水量、氮排放、二氧化碳排放等影响自然系统的关键人文要素历史和未来预估数据集。构建了未来关键人文要素情景,研制了碳中和目标下甲烷和氧化亚氮排放情景和用于驱动全球模式的未来情景,预估了中国碳中和战略的实施对全球变暖的减缓作用,发现中国碳中和对远期和中期全球变暖的减缓作用显著。给出了中国各省份水体氮排放安全阈值及超越时间,阐明了中国粮食产量与氮施肥的关系,提出了在保障粮食安全的前提下减少水体氮排放的有效途径,指出重构城乡养分循环体系是同时保障粮食安全和恢复水质的必要途径。发现全球饱和水汽压差的年际变化与大气二氧化碳浓度上升速率的年际变化显著相关,阐明了饱和水汽压差变化在调控生态系统生产力中的重要角色以及多因素耦合作用在生态系统生产力变化中的复杂影响。建议更全面细致地评估中国各种碳中...     

大气水汽变化及其反馈效应研究进展

大气水汽变化的反馈作用是影响平衡气候系统敏感性的最大反馈作用之一,能够放大其他温室气体增暖的效应,并可能导致极端天气气候事件的发生趋多趋强。因此,全面分析大气水汽的时空分布特征及其长期变化趋势,评估大气水汽反馈的区域气候效应,对于我们深入认识和理解全球变暖背景下区域气候响应的机理具有重要意义。综合国内外最新研究,已基本能够确定水汽反馈效应为一种使得全球增暖加快近一倍的强烈正反馈,并已能够估计其大致变化范围,但是此估计仍存在较大不确定性。随着卫星和探空技术的发展,目前已有的长期水汽资料日趋丰富,但资料之间也存在一些不确定性问题,同时单个资料本身也存在非均一性问题。最新的气候系统模式已能够大致模拟大气水汽的反馈效应,但近年的进展速度却并不令人乐观。我国的水汽观测和水汽反馈效应的研究也已取得长足进步,可以基本确定为水汽变化与地面温度存在正反馈关系,而与降水的关系虽然也较为密切,但因区域气候变化仍存在较大的不一致性。     

Probabilistic climate change projections using neural networks

Anticipated future warming of the climate system increases the need for accurate climate projections. A central problem are the large uncertainties associated with these model projections, and that uncertainty estimates are often based on expert judgment rather than objective quantitative methods. Further, important climate model parameters are still given as poorly constrained ranges that are partly inconsistent with the observed warming during the industrial period. Here we present a neural network based climate model substitute that increases the efficiency of large climate model ensembles by at least an order of magnitude. Using the observed surface warming over the industrial period and estimates of global ocean heat uptake as constraints for the ensemble, this method estimates ranges for climate sensitivity and radiative forcing that are consistent with observations. In particular, negative values for the uncertain indirect aerosol forcing exceeding –1.2 Wm^–2 can be excluded with high confidence. A parameterization to account for the uncertainty in the future carbon cycle is introduced, derived separately from a carbon cycle model. This allows us to quantify the effect of the feedback between oceanic and terrestrial carbon uptake and global warming on global temperature projections. Finally, probability density functions for the surface warming until year 2100 for two illustrative emission scenarios are calculated, taking into account uncertainties in the carbon cycle, radiative forcing, climate sensitivity, model parameters and the observed temperature records. We find that warming exceeds the surface warming range projected by IPCC for almost half of the ensemble members. Projection uncertainties are only consistent with IPCC if a model-derived upper limit of about 5 K is assumed for climate sensitivity.     

Potential impacts of afforestation on climate change and extreme events in Nigeria

Afforestation is usually thought as a good approach to mitigate impacts of warming over a region. This study presents an argument that afforestation may have bigger impacts than originally thought by previous studies. The study investigates the impacts of afforestation on future climate and extreme events in Nigeria, using a regional climate model (RegCM3), forced with global climate model simulations. The impacts of seven afforestation options on the near future (2031–2050, under A1B scenario) climate and the extreme events are investigated. RegCM3 replicates essential features in the present-day (1981–2000) climate and the associated extreme events, and adequately simulates the seasonal variations over the ecological zones in the country. However, the model simulates the seasonal climate better over the northern ecological zones than over the southern ecological zones. The simulated spatial distribution of the extreme events agrees well with the observation, though the magnitude of the simulated events is smaller than the observed. The study shows that afforestation in Nigeria could have both positive and negative future impacts on the climate change and extreme events in the country. While afforestation reduces the projected global warming and enhances rainfall over the afforested area (and over coastal zones), it enhances the warming and reduces the rainfall over the north-eastern part of the country. In addition, the afforestation induces more frequent occurrence of extreme rainfall events (flooding) over the coastal region and more frequent occurrence of heat waves and droughts over the semi-arid region. The positive and negative impacts of the afforestation are not limited to Nigeria; they extend to the neighboring countries. While afforestation lowers the warming and enhances rainfall over Benin Republic, it increases the warming and lowers the rainfall over Niger, Chad and Cameroon. The result of the study has important implication for the ongoing climate change mitigation and adaptation efforts in Nigeria.     

Oceanic Origin of A Recent La Nina-Like Trend in the Tropical Pacific

Global ocean temperature has been rising since the late 1970s at a speed unprecedented during the past century of recordkeeping.This accelerated warming has profound impacts not only on the marine ecosystem and oceanic carbon uptake but also on the global water cycle and climate.During this rapid warming period,the tropical Pacific displays a pronounced La Nin a-like trend,characterized by an intensification of west-east SST gradient and of atmospheric zonal overturning circulation,namely the Walker circulation.This La Nin a-like trend differs from the El Nin o-like trend in warm climate projected by most climate models,and cannot be explained by responses of the global water cycle to warm climate.The results of this study indicate that the intensification of the zonal SST gradient and the Walker circulation are associated with recent strengthening of the upper-ocean meridional overturning circulation.     

全球变化背景下生态气象监测、评价及预警若干问题

IPCC发布的气候变化报告表明,全球变暖是不争的事实,中国气候变化的总体效应为弊大于利;人类必须通过共同努力,应对气候变化的负面效应.在全球变化背景下,生态系统中的生物与环境要素如何变化,相关生态现象与生态过程机制如何,生态问题及其机制如何,均需要全面监测及综合评价才可能通过构建模型、建立基准进行风险预警.这也是目前生态环境损害赔偿及维护生态稳定性的客观需要.生态要素影响并制约着区域气候特征,而特定气候也不同程度地反馈于生态过程,产生不同的生态效果,这些问题的本质就是生态气象耦合关系问题.生态气象就是在生态学及气象学交叉与融合的背景下产生的新学科,并结合相关学科及遥感等信息技术,极大地丰富了学科内涵.未来生态气象监测评估及预警将全面展开,生态科学研究与气象业务服务也将紧密融合,生态气象评估方法趋于规范化与标准化,"互联网+"理念将促进"生态物联网"与生态气象的不断创新与发展.本研究对于美丽中国及生态文明建设（ECC）具有重要现实意义.