全球性气候变化与我国畜牧业

当前全球环境问题受到世界各国的普遍关注。人们越来越深刻地认识到，日益严重的全球性环境恶化已经威胁人类的生存和社会发展。国际社会目前景关心的是全球气候变化、臭氧层破坏、有毒有害废弃物的转移和扩散、生物物种多样性锐减等全球性生态环境问题。同时，水污染与水资源短缺、大气污染与酸雨、土地退化、沙漠化、水土流失、森林减少和海洋污染等环境问题也十分严重。我国是世界上人口最多的国家。在世界７％的耕地面积上承载着占世界２２％的人口。拥有漫长的海岸线，广阔的沿海地区是人口和工业最密集的地区。我国水资源短缺，且分布不均。气候变化的不利影响，将给我国造成严重的威胁。本文就引起全球性气候变化的原因，气候变化对我国水资源可能产生的影响，气候变化对我国牧业布局、结构及对家畜健康和生产力的影响等方面作一概念性介绍，供畜牧兽医同行参考。

科学家称地球旋转轴倾角发生多次变化

据俄罗斯《纽带》网报道,日前有科学家宣布,在最近4000万年中,地球旋转轴线的倾斜角度曾发生多次明显变化,一度从22.1度增加到了24.5度,目前倾角为23.5度。专家们指出。

地球气候变暖对我国的影响

气象学家测定,近15年来,地球上的气温平均每年升高了0.3℃,预计到本世纪末,气温还将上升1.5℃。有的气象学家甚至说,如果各国继续大量燃烧石化燃料,那么在下一个100年中。

珠三角咸潮的形成机制及防范措施

介绍了咸潮的概念及珠三角咸潮的形成机制、危害和防范措施。珠三角咸潮的形成机制主要有自然地理条件、全球性气候变化(包括干旱高温和海平面上升)、采沙过度及疏浚航道、经济人口增长、用水浪费、防咸抗灾设施制度不完善等。解决措施必须立足于全流域资源的合理配置,建立长效防范机制。文中最后提出有关珠三角咸潮的一些看法及将来的研究方向。

大气污染物的主要化学成份及其净化

我国的大气污染是世界上最严重的国家之一。气体状态污染物种类极多,而量大面广的大气污染主要是以 SO2为主的含硫化合物、以 NO 和 NO2为主的含氮化合物、及含碳化合物等。根据对主要大气污染物的分类统计分析表明,其主要来源是煤炭直接燃烧、机动车辆。

畜牧基础科学

S811.1 960386全球性气候变化与我国畜牧业/邵庆均(浙江农业大学畜牧兽医系 310029)//家畜生态.-1995,16(2).-37～40当前全球环境问题受到世界各国的普遍关注.人们越来越深刻地认识到,日益严重的全球性环境变化已经威胁人类的生存和社会发展.国际社会目前最关心的是全球气候变化、臭氧层破坏、有毒有害废弃物的转移和扩散。

Spatial Scale Effects of Water Erosion Dynamics:Complexities, Variabilities, and Uncertainties

Severe water erosion is notorious for its harmful effects on land-water resources as well as local societies. The scale effects of water erosion, however, greatly exacerbate the difficulties of accurate erosion evaluation and hazard control in the real world. Analyzing the related scale issues is thus urgent for a better understanding of erosion variations as well as reducing such erosion. In this review article, water erosion dynamics across three spatial scales including plot, watershed, and regional scales were selected and discussed. For the study purposes and objectives, the advantages and disadvantages of these scales all demonstrate clear spatial-scale dependence. Plot scale studies are primarily focused on abundant data collection and mechanism discrimination of erosion generation, while watershed scale studies provide valuable information for watershed management and hazard control as well as the development of quantitatively distributed models. Regional studies concentrate more on large-scale erosion assessment, and serve policymakers and stakeholders in achieving the basis for regulatory policy for comprehensive land uses. The results of this study show that the driving forces and mechanisms of water erosion variations among the scales are quite different. As a result, several major aspects contributing to variations in water erosion across the scales are stressed: differences in the methodologies across various scales, different sink-source roles on water erosion processes, and diverse climatic zones and morphological regions. This variability becomes more complex in the context of accelerated global change. The changing climatic factors and earth surface features are considered the fourth key reason responsible for the increased variability of water erosion across spatial scales.

Impact of Regional Development on Carbon Emission: Empirical Evidence Across Countries

Global warming is recently an urgent issue worldwide. The increase of carbon emissions induced by human economic activi- ties has become a major driving force behind global climate change. Thus, as a matter of social responsibility, reasonable carbon con- straints should be implemented to ensure environmental security and sustainable development for every country. Based on a summary of studies that examined the relationship between carbon emissions and regional development, this paper shows that human activity-led carbon emission is caused by the combination of several influencing factors, including population size, income level, and technical pro- gress. Thus, a quantitative model derived from IPAT-ImPACT-Kaya series and STIRPAT models was established. Empirical analysis using multivariate nonlinear regression demonstrated that the origins of growing global carbon emission included the increasing influ- encing elasticity of the population size and the declining negative effect of technical progress. Meanwhile, in context of classification of country groups at different income levels, according to the comparison of fluctuating patterns of the influencing elasticity, technical progress was found as the main factor influencing carbon emission levels in high-income countries, and population size might he the controlling factor in middle-income countries. However, for low-income countries, the nonlinear relationship between carbon emission and its influencing factors was not significant, whereas population growth was identified as an important potential driving force in future carbon emissions. This study can therefore provide a reference for the formulation of policies on carbon constraints, especially to de- velop more efficient carbon mitigating policies for countries at different income levels.

Sources of uncertainty in exploring rangeland phenology： A case study in an alpine meadow on the central Tibetan Plateau

Global climate change has been found to substantially influence the phenology of rangeland,especially on the Tibetan Plateau. However, there is considerable controversy about the trends and causes of rangeland phenology owing to different phenological exploration methods and lack of ground validation. Little is known about the uncertainty in the exploration accuracy of vegetation phenology.Therefore, in this study, we selected a typical alpine rangeland near Damxung national meteorological station as a case study on central Tibetan Plateau, and identified several important sources influencing phenology to better understand their effects on phenological exploration. We found man-made land use was not easily distinguished from natural rangelands, and therefore this may confound phenological response to climate change in the rangeland. Change trends of phenology explored by four methods were similar, but ratio threshold method(RTM) was more suitable for exploring vegetation phenology in terms of the beginning of growing season(BGS) and end of growing season(EGS). However, some adjustments are needed when RTM is used in extreme drought years. MODIS NDVI/EVI dataset was most suitable for exploring vegetation phenology of BGS and EGS. The discrimination capacities of vegetation phenology declined with decreasing resolution of remote sensing images from MODIS to GIMMS AVHRR datasets. Additionally, distinct trends of phenological change rates were indicated in different terrain conditions, with advance of growing season in high altitudes but delay of season in lower altitudes. Therefore, it was necessary to eliminate interference of complex terrain and man-made land use to ensure the representativeness of natural vegetation. Moreover, selecting the appropriate method to explore rangelands and fully considering the impact of topography are important to accurately analyze the effects of climate change on vegetation phenology.

The Project Siberian High in CMIP5 Models

The Siberian high(SH)experienced a decline from the 1970s to 1990s and a recovery in recent years.The evolution of the SH under global warming is unclear.In this study,41 Coupled Model Intercomparison Project Phase 5(CMIP5)climate models are evaluated in terms of their ability to simulate the temporal evolution of the SH in the 19th and 20th centuries and the spatial pattern of the SH during 1981–2005.The results show that 12models can capture the temporal evolution of the SH center intensity(SHCI)for 1872–2005.The linear correlation coefficient between the SHCI from the Twentieth Century Reanalysis and the simulated SHCI from the multi-model ensemble(MME)of the 12 models is 0.3 on annual and inter-annual scales(above the 99%confidence level).On decadal and multi-decadal time scales,the MME also captures the pronounced reduction(between 1981–2000and 1881–1900 period)and the recovery(during1991–2005)of the SH intensity.Finally,the future evolution of the SH is investigated using the MME of the 12models under the+4.5 and+8.5 W m-2 Representative Concentration Pathway(RCP)scenarios(RCP4.5 and RCP8.5).It is shown that the SHCI,similar to the SHCI in the 20th century,has no significant long-term trend in the 21st century under global warming(RCP8.5 scenario).At the end of 21st century(2081–2100),the SH shows stronger interannual variability than the SH at the end of20th century(1981–2000).The increased interannual variability likely favors the increased interannual variability in winter air temperature over midlatitude Eurasia at the end of 21st century.

地球变暖了

科学家在南极考察发现,70年代以来,南极冰域面积缩小了2.85万平方公里,南极的霍尔湖冰帽薄了3～6米。北半球也同样,俄罗斯的破冰船发现北冰洋冰层厚度平均薄了20％～30％。

Advances in the reintroduction of rare and endangered wild plant species

Human disturbance and climate change have increased the risk of extinction for rare and endangered wild plant species.One effective way to conserve these rare and endangered species is through reintroduction.In this review,we summarize the advances in wild plant reintroduction from five perspectives:the establishment of reintroduction biology as an important tool for biodiversity conservation;the importance of genetic diversity in reintroduction;reintroduction under global climate change;recruitment limitation in reintroduction;and reintroduction and ecological restoration.In addition,we consider the future of plant reintroduction strategies.

Soil Microbiological Activity and Carbon Dynamics in the Current Climate Change Scenarios:A Review

Microbial activities are affected by a myriad of factors with end points involved in nutrient cycling and carbon sequestration issues.Because of their prominent role in the global carbon balance and their possible role in carbon sequestration, soil microbes are very important organisms in relation to global climate changes. This review focuses mainly on the responses of soil microbes to climate changes and subsequent effects on soil carbon dynamics. An overview table regarding extracellular enzyme activities(EAA) with all relevant literature data summarizes the effects of different ecosystems under various experimental treatments on EAA. Increasing temperature, altered soil moisture regimes, and elevated carbon dioxide significantly affect directly or indirectly soil microbial activities.High temperature regimes can increase the microbial activities which can provide positive feedback to climate change, whereas lower moisture condition in pedosystem can negate the increase, although the interactive effects still remain unanswered. Shifts in soil microbial community in response to climate change have been determined by gene probing, phospholipid fatty acid analysis(PLFA),terminal restriction length polymorphism(TRFLP), and denaturing gradient gel electrophoresis(DGGE), but in a recent investigations,omic technological interventions have enabled determination of the shift in soil microbe community at a taxa level, which can provide very important inputs for modeling C sequestration process. The intricacy and diversity of the soil microbial population and how it responds to climate change are big challenges, but new molecular and stable isotope probing tools are being developed for linking fluctuations in microbial diversity to ecosystem function.

Climate change and global cycling of persistent organic pollutants:A critical review

Climate warming, one of the main features of global change, has exerted indelible impacts on the environment, among which the impact on the transport and fate of pollutants has aroused widespread concern. Persistent organic pollutants(POPs) are a class of pollutants that are transported worldwide. Determining the impact of climate warming on the global cycling of POPs is important for understanding POP cycling processes and formulating relevant environmental policies. In this review, the main research findings in this field over the past ten years are summarized and the effects of climate warming on emissions, transport, storage, degradation and toxicity of POPs are reviewed. This review also summarizes the primary POP fate models and their application. Additionally, research gaps and future research directions are identified and suggested. Under the influence of climate change, global cycling of POPs mainly shows the following responses.(1) Global warming directly promotes the secondary emission of POPs; for example, temperature rise will cause POPs to be re-released from soils and oceans, and melting glaciers and permafrost can re-release POPs into freshwater ecosystems.(2) Global extreme weather events, such as droughts and floods, result in the redistribution of POPs through intense soil erosion.(3) The changes in atmospheric circulation and ocean currents have significantly influenced the global transport of POPs.(4) Climate warming has altered marine biological productivity, which has changed the POP storage capacity of the ocean.(5) Aquatic and terrestrial food-chain structures have undergone significant changes, which could lead to amplification of POP toxicity in ecosystems.(6) Overall, warming accelerates the POP volatilization process and increases the amount of POPs in the environment, although global warming facilitates their degradation at the same time.(7) Various models have predicted the future environmental behaviors of POPs. These models are used to assist governments in comprehensively considering the impact of global warming on the environmental fate of POPs and therefore controlling POPs effectively. Future studies should focus on the synergistic effects of global changes on the cycling of POPs. Additionally, the interactions among global carbon cycling, water cycling and POP cycling will be a new research direction for better understanding the adaptation of ecosystems to climate change.

Coherent variations of the obliquity components in global ice volume and ocean carbon reservoir over the past 5 Ma

The Milankovid theory stresses that the summer insolation in the high northern latitudes that is dominated by the precession cycle controls the glacial/interglacial cycles in global climate change. If the climate system responds linearly to the external insolation forcing, the precession cycle of 23 or 19 ka should dominate the variations in the climatic proxy records. I per- formed spectral and evolutive cross spectral analyses on the high resolution benthic ~80 and oa3C records from the South China Sea and the North Atlantic, the proxies of global ice volume and ocean carbon reservoir respectively. I found that the obliquity instead of the eccentricity or the precession is the most marked cycle in the global ice volume and ocean carbon res- ervoir variations over the past 5 Ma. The analysis further reveals that only at the obliquity band instead of the eccentricity or the precession band does the global ice volume and ocean carbon reservoir display consistently high coherency and stable phase relationship over the past 5 Ma. The consistently positive or near-zero phases of the benthic -o^SO relative to the benthic ff3C at the obliquity band suggest that the global carbon cycle is involved in the polar ice sheet growth as an important internal feedback, not a determinative driving factor. The obliquity instead of the precession or the eccentricity takes the dominant role of driving the global climate change during the Pliocene and Pleistocene.