How changes in diet and trade patterns have shaped the N cycle at the national scale: Spain (1961–2009)

During the last five decades (1961–2009), Spain has experienced a considerable expansion in the nutrient cycle of its agricultural sector and, in particular, a threefold increase in anthropogenic reactive nitrogen inputs, from 536 Gg N year^?1 in 1961–1965 to 1673 Gg N year^?1 in 2005–2009. Import of feed (soybean, cereals, and cakes) from America and Europe to supply a growing livestock population constitutes the largest share of this increase, along with intensification of synthetic fertilizer use. While in the early 1960s, Spain was nearly self-sufficient in terms of food and feed supply, the net import of agricultural products presently equals domestic crop production, when expressed in terms of nitrogen content (ca. 650 Gg N year^?1). The most important driver of this shift appears to be the rapid change in domestic consumption patterns, which evolved from a typical Mediterranean diet to an animal-protein-rich diet similar to the North European and American diets. Besides livestock production mostly for national consumption, the Spanish agricultural system has specialized in vegetal products with low N content such as olive oil, wine, vegetables, and citrus fruit, which are for the most part exported. The nitrogen load exported outside the Spanish borders by rivers is very low (6.5 % of the total net N input). As a result of the high import and low export of reactive nitrogen, the Spanish mainland is suffering from considerable pollution by local emissions of reactive nitrogen forms to air and water.     

四湖地区地下水“三氮”含量及时空分布特征分析

在4次地下水水质监测的基础上，对潜水和浅层承压水的“三氮”含量进行了季节变化和空间差异分析，同时探讨了时空变化的影响因素。分析结果表明：（1）地下水氨氮浓度超标率较高，承压水中浓度明显高于潜水，4次采样结果承压水氨氮浓度超标率均在50% 以上；（2）硝酸盐氮和亚硝酸盐氮含量在承压水中能达到良好的标准，在潜水中超标率高；（3）氨氮浓度季节变化明显，9月份浓度显著高于4、6和11月。硝酸盐氮和亚硝酸盐氮在潜水中6月份浓度最高，在承压水中季节变化不明显；（4）地下水氨氮含量空间变异性强，浓度较高的多集中在流经洪湖的内荆河两侧区域。研究区地下水水质受气象因素、农业活动、农村生活污染以及氧化还原环境的综合影响     

丹江口库区典型小流域地表径流氮素动态变化

探明面源污染特征对制定丹江口水库水质保障体系具有重要意义。以胡家山小流域为研究对象，对村落和林 耕复合两种典型土地利用类型和流域各集水区出口地表径流氮浓度进行了连续监测。结果表明：村落降雨径流中总氮、硝态氮浓度较高，其中总氮均值超过20 mg/L，变化幅度都不大；氨氮浓度较低，但变化剧烈，这种氮浓度演变过程和降雨强度关系密切。硝态氮是村落氮输出的主要形态，占总氮输出的6031%～9655%，与总氮输出变化过程具有显著的相关性。林 耕地的氮浓度相对较低，总氮表现出上升—下降—平稳—上升的变化过程，硝态氮和总氮变化有着显著的相关性。在空间传输过程中，小流域下游氮浓度表现出稀释和富集两种效应，其中村落的氮输出对两种效应影响较大；在时间上，受耕作制度和气象变化，各集水区的氮浓度季节性变化明显，总氮浓度表现出春季>夏季>秋季>冬季，硝氮浓度表现出秋季>夏季>春季>冬季。胡家山小流域径流中氮素的含量均高于水库水体氮素含量，总氮高于地表水Ⅴ类水质标准，需要加强对小流域污染源的控制与处理，尤其是对村落径流的处理。
     

Swedish nutrient reduction policies: an evaluation of cost-effectiveness

Since more than 30 years, the Swedish government as well as other governments in the drainage basin strives toward a reduction in nutrient loads to Baltic Sea coastal waters in order to combat eutrophication of the sea. In spite of this, the cost-effectiveness of actual environmental policy for meeting Baltic Sea nutrient targets has not been evaluated by national or international bodies in the region. The aim of this paper is to evaluate Swedish national nitrogen and phosphorus policies with regard to cost-effectiveness. This is done through a comparison of nutrient measures implemented through environmental policy decisions 1995–2005 with cost-effective policies for present national as well as Baltic Sea Action Plan (BSAP) targets. The cost-effective measures are calculated using an empirical programming model including all countries adjacent to the Baltic Sea. Calculations show that measures that jointly reduce nitrogen and phosphorus are hardly applied in actual policy and that reductions in the agricultural sector are much smaller than is cost-effective. Data show, surprisingly, that considerable reductions have been carried out in the Bothnian Sea catchment in spite of there being no nutrient reduction target for this catchment. Results suggest also that the Swedish costs for meeting the new and geographically more restricted targets under the BSAP can be reduced if a policy with less restrictions on the location of phosphorus abatement is applied, compared to what is now suggested.     

Addressing food supply chain and consumption inefficiencies: potential for climate change mitigation

Globally, more than 30 % of all food that is produced is ultimately lost and/or wasted through inefficiencies in the food supply chain. In the developed world this wastage is centred on the last stage in the supply chain; the end-consumer throwing away food that is purchased but not eaten. In contrast, in the developing world the bulk of lost food occurs in the early stages of the supply chain (production, harvesting and distribution). Excess food consumption is a similarly inefficient use of global agricultural production; with almost 1 billion people now classed as obese, 842 million people are suffering from chronic hunger. Given the magnitude of greenhouse gas emissions from the agricultural sector, strategies that reduce food loss and wastage, or address excess caloric consumption, have great potential as effective tools in global climate change mitigation. Here, we examine the challenges of robust quantification of food wastage and consumption inefficiencies, and their associated greenhouse gas emissions, along the supply chain. We find that the quality and quantity of data are highly variable within and between geographical regions, with the greatest range tending to be associated with developing nations. Estimation of production-phase GHG emissions for food wastage and excess consumption is found to be similarly challenging on a global scale, with use of IPCC default (Tier 1) emission factors for food production being required in many regions. Where robust food waste data and production-phase emission factors do exist—such as for the UK—we find that avoiding consumer-phase food waste can deliver significant up-stream reductions in GHG emissions from the agricultural sector. Eliminating consumer milk waste in the UK alone could mitigate up to 200 Gg CO₂e year^?1; scaled up globally, we estimate mitigation potential of over 25,000 Gg CO₂e year^?1.     

Characteristics of oxidant precursor emissions from anthropogenic sources in the United States

Hydrocarbons (HC) and nitrogen oxides (NO_x) have been identified as the most important precursor pollutants for oxidant formation in the atmosphere. These pollutants are emitted both from natural and anthropogenic sources; however, these two types of sources are generally geographically separated. Anthropogenic emissions are dominant in and around urban centers, where the majority of severe oxidant problems occur. Based on data gathered by the MAP3S/RAINE emissions inventory project, anthropogenic emissions of HC in the conterminous United States were 24.8 million metric tons in 1979. HC emissions were predominantly from area sources, the transportation sector being the largest contributor with 39.8% of the total. State-by-state breakdowns are also included. Based on analyses by other emissions inventory projects, the nonreactive fraction of the emissions from the transportation sector is less than 20% by weight. The highest proportion of HC emissions occur at low altitudes (0–50 m range) in high population density areas. Anthropogenic emissions of NO_x were 23.7 million metric tons in 1979; 50.8% were from point sources. The transportation sector and the electric utilities sector account for 37.1% and 30.9% of the NO_x emissions, respectively. The NO₂ fraction of the emissions from the transportation and electric utilities sectors is less than 10% by weight, based on NO/NO₂ speciation data from two other emissions inventories. Highest rates of NO_x emissions occur in high population density areas and are released at low altitude (0–50 m); three areas of high electric generating capacity were found to have high release altitudes.     

Protein futures for Western Europe: potential land use and climate impacts in 2050

Multiple production and demand side measures are needed to improve food system sustainability. This study quantified the theoretical minimum agricultural land requirements to supply Western Europe with food in 2050 from its own land base, together with GHG emissions arising. Assuming that crop yield gaps in agriculture are closed, livestock production efficiencies increased and waste at all stages reduced, a range of food consumption scenarios were modelled each based on different ‘protein futures’. The scenarios were as follows: intensive and efficient livestock production using today’s species mix; intensive efficient poultry–dairy production; intensive efficient aquaculture–dairy; artificial meat and dairy; livestock on ‘ecological leftovers’ (livestock reared only on land unsuited to cropping, agricultural residues and food waste, with consumption capped at that level of availability); and a ‘plant-based eating’ scenario. For each scenario, ‘projected diet’ and ‘healthy diet’ variants were modelled. Finally, we quantified the theoretical maximum carbon sequestration potential from afforestation of spared agricultural land. Results indicate that land use could be cut by 14–86 % and GHG emissions reduced by up to approximately 90 %. The yearly carbon storage potential arising from spared agricultural land ranged from 90 to 700 Mt CO₂ in 2050. The artificial meat and plant-based scenarios achieved the greatest land use and GHG reductions and the greatest carbon sequestration potential. The ‘ecological leftover’ scenario required the least cropland as compared with the other meat-containing scenarios, but all available pasture was used, and GHG emissions were higher if meat consumption was not capped at healthy levels.     

MRIO model-based study on water nitrogen pollution transfer embodied in international trade

This study uses the global pollutant emission databases and global input–output model in 2015 to calculate the impact of international trade on global water nitrogen emission patterns, based on considering the total amount of pollutant transfer and pollutant emission intensity of trade flows The main conclusions are as follows: (1) There are always a large amount of water nitrogen emissions transferring from developed economies to developing economies embodied in their bilateral trade activities. Small amount of transfers are of some areas with similar endowments of agricultural resources or long distances. (2) In 2015, the net import of water nitrogen pollution embodied in China’s trade was 160,000 tons, accounting for 2.72% of the global water nitrogen imports. The sharp increases in cereal imports, together with high food storage as well as high pollution intensity embedded in trade are the main reason. It is recommended that through applying alleviations such as agricultural machinery assistance and technical training to accelerate the transfer and spread of agricultural technology in Africa, Asia, and other regions, thus helping increase agricultural production productivity in underdeveloped areas and reducing the pollution intensity embodied in trade flows from underdeveloped areas to developed areas.     

A quantitative integrated assessment of pollution prevention achieved by Integrated Pollution Prevention Control licensing

This paper presents an innovative, quantitative assessment of pollution avoidance attributable to environmental regulation enforced through integrated licensing, using Ireland's pharmaceutical-manufacturing sector as a case study. Emissions data reported by pharmaceutical installations were aggregated into a pollution trend using an Environmental Emissions Index (EEI) based on Lifecycle Assessment methodologies. Complete sectoral emissions data from 2001 to 2007 were extrapolated back to 1995, based on available data. Production volume data were used to derive a sectoral production index, and determine ‘no-improvement’ emission trends, whilst questionnaire responses from 20 industry representatives were used to quantify the contribution of integrated licensing to emission avoidance relative to these trends. Between 2001 and 2007, there was a 40% absolute reduction in direct pollution from 27 core installations, and 45% pollution avoidance relative to hypothetical ‘no-improvement’ pollution. It was estimated that environmental regulation avoided 20% of ‘no-improvement’ pollution, in addition to 25% avoidance under business-as-usual. For specific emissions, avoidance ranged from 14% and 30 kt a^− 1 for CO₂ to 88% and 598 t a^− 1 for SO_x. Between 1995 and 2007, there was a 59% absolute reduction in direct pollution, and 76% pollution avoidance. Pollution avoidance was dominated by reductions in emissions of VOCs, SO_x and NO_x to air, and emissions of heavy metals to water. Pollution avoidance of 35% was attributed to integrated licensing, ranging from between 8% and 2.9 t a^− 1 for phosphorus emissions to water to 49% and 3143 t a^− 1 for SO_x emissions to air. Environmental regulation enforced through integrated licensing has been the major driver of substantial pollution avoidance achieved by Ireland's pharmaceutical sector — through emission limit values associated with Best Available Techniques, emissions monitoring and reporting requirements, and performance targets specified in environmental management plans. This compliant sector offers a positive, but not necessarily typical, case study of IPPC effectiveness.     

洞庭湖渔业水域氮磷时空分布分析

根据2000~2011 年对洞庭湖渔业环境监测数据,对东洞庭湖、南洞庭湖、西洞庭湖和三江口4 个不同渔业水域的总氮、总磷、氨氮和硝酸盐氮浓度的时空分布进行分析。结果表明：（1）洞庭湖总氮、总磷、氨氮和硝酸盐氮浓度均值分别为143±041、009±003、032±005和063±011 mg/L,总氮最大值为2009 年5 月丰水期东洞庭湖的鹿角采样点,为480 mg/L,总磷最大值为2008 年1 月枯水期鹿角采样点,为0417 mg/L,分析得知,所有采样点中鹿角采样点较其它采样点污染严重;（2）洞庭湖氮、磷浓度年均值间差异性显著（P<005）,除总磷变化规律不明显外,总氮、氨氮和硝酸盐氮的年浓度均值总体呈上升趋势,与此同时,洞庭湖在丰水期、平水期和枯水期的氮、磷浓度均值间也存在显著性差异（P<005）,平水期总氮平均浓度最高,枯水期总磷浓度均值最高;（3）东洞庭湖、南洞庭湖、西洞庭湖和三江口4 个湖区氮磷浓度均值间也存在显著性差异（P<005）,总氮、总磷和硝酸盐氮均值以三江口最高,氨氮均值以东洞庭湖最高,主要受城市污水和工业污水影响严重;（4）面源污染是洞庭湖主要污染方式,也是造成洞庭湖水体富营养化程度加剧的主要因素,面源污染占洞庭湖污染总量的94%～99%,主要包括农业污染、城市生活污水和畜牧水产养殖业污染;点源污染占洞庭湖污染总量的1%～6%,主要为工业污水和城市生活污水的排放,虽然排放量相对于面源污染较小,但是工业污水含有高浓度的有毒物质,且瞬时排放量大,很容易造成渔业污染事故,严重时会影响到人类的健康;（5）参照《地表水质量标准》（GB3838 2002）中的水质分类标准,所有监测年份中,仅2000 年水质为III 类,其它年份水质类型多为IV 类,部分年份为V 类,推断洞庭湖渔业水域大部分处于中度污染状态,部分湖区处于重度污染,根据《渔业水质标准》和鱼类对水环境质量的需求,洞庭湖水质不利于鱼类繁殖、早期发育、索饵和越冬等行为,势必会造成洞庭湖渔业资源的衰退     

基于BMPs的鄱阳湖区小流域农村面源污染控制

鄱阳湖小流域农村面源污染严重，环境问题不断加剧。通过背景值调查与污染源解析，显示农村生活和种植业是鄱阳湖小流域农村面源污染的主要来源。采取集成式BMPs模式，将源头控制与末端治理相结合，充分利用当地优势，合理搭配植物缓冲带、沟渠湿地、人工湿地，兼性塘等，实现氮、磷流失的有效拦截，达到有效控制示范区小流域农村面源污染目的，从而为鄱阳湖农村面源污染控制提供借鉴。结果表明： BMPs系统污染物去除能力高，运行成本低。系统单位面积削减总量分别为CODcr 71017 kg、SS 11491 kg、TP 408 kg、TN 3593 kg、NO-3 N 474 kg、NH+4 N 1918 kg，而运行成本不到01元/t。整个系统中尤以表面流人工湿地减污效果最好，耐负荷冲击能力最强。沟渠湿地整体去污能力不低，但耐冲击负荷能力弱，易受外界因素的影响。为加强减污效果，可通过完善生态系统尤其是挺水性植物加以改进     

火电厂氮氧化物排放量动态更新方法研究

有效控制氮氧化物是我国“十二五”环保重点工作之一，如何实现氮氧化物减排监管和核查核算显得十分重要，但是我国尚未建立科学合理的行业氮氧化物排放量核算核查方法。以火电行业为研究对象，首次系统提出火电行业氮氧化物排放量的动态更新方法。提出3种不同的污染源排放动态更新方法：源活动强度动态更新法、污染源增减动态更新法、综合排放因子动态更新法，详细分析了方法原理、计算公式和使用范围，并在2008年我国火电氮氧化物排放量基础上，分别对2009年火电氮氧化物排放量进行了动态更新核算     

Importance of atmospherically deposited nitrogen to the annual nitrogen budget of the Neuse River estuary,North Carolina

Wet deposition of nitrogen, as NH(4)(+), NO(3)(-), and organic N, contributes up to 50% of the total externally supplied or 'new' N flux to the Neuse River Estuary (North Carolina). Excessive nitrogen (N) loading to N-sensitive waters such as the Neuse River Estuary has been linked to changes in microbial and algal community composition and function (harmful algal blooms), hypoxia/anoxia, and fish kills. In a 4-year study from July 1996 to July 2000, the weekly wet deposition of NH(4)(+), NO(3)(-), and dissolved organic N was calculated, based on concentration and precipitation measurements, at 11 sites on a northwest-southeast transect in the watershed. Data from this period indicate that the annual mean total wet atmospherically deposited (AD)-N flux was 11 kg ha(-1) year(-1). Deposition was fairly evenly distributed between nitrate, ammonium, and organics (32%, 32%, and 36%, respectively). Seasonally, the summer (June-August) months contained the highest weekly wet total N deposition; this trend was not driven by precipitation amount. Estimates of watershed N retention and in-stream riverine processing revealed that the AD-N flux contributed an estimated 20% (range of 15-51%) of the total 'new' N flux to the estuary, with direct deposition of N to the estuary surface accounting for 6% of the total 'new' N flux. This study did not measure the dry depositional flux, which may double the contribution of AD-N to the estuary. The AD-N is an important source of 'new' N to the Neuse River Estuary as well as other estuarine and coastal ecosystems downwind of major emission sources. As such, AD-N should be included in effective nutrient mitigation and management efforts for these N-sensitive waters.     

经济增长、国际贸易与污染排放的关系研究——基于美国和中国SO2排放的实证分析

在世界经济一体化进程中,国际贸易成为影响各国环境污染变化的重要因素,将其纳入经济增长与环境污染间关系的分析框架是环境学界关注的一个重要问题。本文基于联立方程模型,从经济产出、污染排放、污染治理和国际贸易等四个方面探讨了经济增长与污染排放的相互作用机理,并以美国、中国SO2排放为例进行了实证研究。结果表明:污染排放对经济产出有影响,且对美国和中国分别为正作用和负作用。经济增长增加了两国国内污染排放,且中国增加的相对更多。而污染治理均减少了国内污染排放,美、中的污染减排弹性系数分别为-0.277和-0.417。国际贸易对美国起到污染减排作用,对中国的影响不显著,考虑到贸易对中国经济增长的拉动作用,其经济规模间接污染效应不容忽视。对于中国而言,加大污染治理投资、改善贸易进出口状况、降低经济发展过程中的污染排放是实现经济与环境协调发展的有效途径。     

Water balance and nitrate leaching losses under intensive crop production with Ochric Aquic Cambosols in North China Plain

A 2-year field experiment was conducted in an Ochric Aquic Cambosols on a 1-ha field with rotation of winter wheat-summer corn located in Fengqiu County in North China Plain from 1 October 1998 to 30 September 2000 to quantify water balance and evaluate soil water loss by deep drainage and nitrate loss by leaching out of the root zone under the current agricultural practices. Considerable deep drainage was found especially in 1999-2000, during which period up to 273.9 mm of water, accounting for 60.6% of total amount of irrigation and 24.7% of total surface input (rainfall+irrigation), was lost by deep drainage. Even in both wheat cropping seasons when total amount of surface input was less than total actual evapotranspiration, 84.0 and 121.3 mm water was lost by drainage in 1999 and 2000, respectively. Soil NO3(-)-N was transported to deeper soil layers during the growing seasons and considerable amount of NO3(-)-N accumulated at 170 cm soil layer (the bottom of root zone) during the September-October period (the harvest time of summer corn) every year. About 28.6 kg N ha-1 was lost by leaching out of the root zone in 1998-1999 and 81.8 kg N ha-1 in 1999-2000, accounting for 5.9% and 15.7% of total nitrogen (N) inputs, respectively. The significant deep drainage and nitrate leaching loss were attributed to excessive and inappropriate irrigation and nitrogen (N) fertilization, which may result in severe groundwater pollution if current agricultural managements are not changed.     

Ecological and toxicological effects of inorganic nitrogen pollution in aquatic ecosystems: A global assessment

We provide a global assessment, with detailed multi-scale data, of the ecological and toxicological effects generated by inorganic nitrogen pollution in aquatic ecosystems. Our synthesis of the published scientific literature shows three major environmental problems: (1) it can increase the concentration of hydrogen ions in freshwater ecosystems without much acid-neutralizing capacity, resulting in acidification of those systems; (2) it can stimulate or enhance the development, maintenance and proliferation of primary producers, resulting in eutrophication of aquatic ecosystems; (3) it can reach toxic levels that impair the ability of aquatic animals to survive, grow and reproduce. Inorganic nitrogen pollution of ground and surface waters can also induce adverse effects on human health and economy. Because reductions in SO2 emissions have reduced the atmospheric deposition of H2SO4 across large portions of North America and Europe, while emissions of NOx have gone unchecked, HNO3 is now playing an increasing role in the acidification of freshwater ecosystems. This acidification process has caused several adverse effects on primary and secondary producers, with significant biotic impoverishments, particularly concerning invertebrates and fishes, in many atmospherically acidified lakes and streams. The cultural eutrophication of freshwater, estuarine, and coastal marine ecosystems can cause ecological and toxicological effects that are either directly or indirectly related to the proliferation of primary producers. Extensive kills of both invertebrates and fishes are probably the most dramatic manifestation of hypoxia (or anoxia) in eutrophic and hypereutrophic aquatic ecosystems with low water turnover rates. The decline in dissolved oxygen concentrations can also promote the formation of reduced compounds, such as hydrogen sulphide, resulting in higher adverse (toxic) effects on aquatic animals. Additionally, the occurrence of toxic algae can significantly contribute to the extensive kills of aquatic animals. Cyanobacteria, dinoflagellates and diatoms appear to be major responsible that may be stimulated by inorganic nitrogen pollution. Among the different inorganic nitrogenous compounds (NH4+, NH3, NO2-, HNO2NO3-) that aquatic animals can take up directly from the ambient water, unionized ammonia is the most toxic, while ammonium and nitrate ions are the least toxic. In general, seawater animals seem to be more tolerant to the toxicity of inorganic nitrogenous compounds than freshwater animals, probably because of the ameliorating effect of water salinity (sodium, chloride, calcium and other ions) on the tolerance of aquatic animals. Ingested nitrites and nitrates from polluted drinking waters can induce methemoglobinemia in humans, particularly in young infants, by blocking the oxygen-carrying capacity of hemoglobin. Ingested nitrites and nitrates also have a potential role in developing cancers of the digestive tract through their contribution to the formation of nitrosamines. In addition, some scientific evidences suggest that ingested nitrites and nitrates might result in mutagenicity, teratogenicity and birth defects, contribute to the risks of non-Hodgkin's lymphoma and bladder and ovarian cancers, play a role in the etiology of insulin-dependent diabetes mellitus and in the development of thyroid hypertrophy, or cause spontaneous abortions and respiratory tract infections. Indirect health hazards can occur as a consequence of algal toxins, causing nausea, vomiting, diarrhoea, pneumonia, gastroenteritis, hepatoenteritis, muscular cramps, and several poisoning syndromes (paralytic shellfish poisoning, neurotoxic shellfish poisoning, amnesic shellfish poisoning). Other indirect health hazards can also come from the potential relationship between inorganic nitrogen pollution and human infectious diseases (malaria, cholera). Human sickness and death, extensive kills of aquatic animals, and other negative effects, can have elevated costs on human economy, with the recreation and tourism industry suffering the most important economic impacts, at least locally. It is concluded that levels of total nitrogen lower than 0.5-1.0 mg TN/L could prevent aquatic ecosystems (excluding those ecosystems with naturally high N levels) from developing acidification and eutrophication, at least by inorganic nitrogen pollution. Those relatively low TN levels could also protect aquatic animals against the toxicity of inorganic nitrogenous compounds since, in the absence of eutrophication, surface waters usually present relatively high concentrations of dissolved oxygen, most inorganic reactive nitrogen being in the form of nitrate. Additionally, human health and economy would be safer from the adverse effects of inorganic nitrogen pollution.     

Biophysical suitability,economic pressure and land-cover change: a global probabilistic approach and insights for REDD+

There has been a concerted effort by the international scientific community to understand the multiple causes and patterns of land-cover change to support sustainable land management. Here, we examined biophysical suitability, and a novel integrated index of “Economic Pressure on Land” (EPL) to explain land cover in the year 2000, and estimated the likelihood of future land-cover change through 2050, including protected area effectiveness. Biophysical suitability and EPL explained almost half of the global pattern of land cover (R ² = 0.45), increasing to almost two-thirds in areas where a long-term equilibrium is likely to have been reached (e.g. R ² = 0.64 in Europe). We identify a high likelihood of future land-cover change in vast areas with relatively lower current and past deforestation (e.g. the Congo Basin). Further, we simulated emissions arising from a “business as usual” and two reducing emissions from deforestation and forest degradation (REDD) scenarios by incorporating data on biomass carbon. As our model incorporates all biome types, it highlights a crucial aspect of the ongoing REDD + debate: if restricted to forests, “cross-biome leakage” would severely reduce REDD + effectiveness for climate change mitigation. If forests were protected from deforestation yet without measures to tackle the drivers of land-cover change, REDD + would only reduce 30 % of total emissions from land-cover change. Fifty-five percent of emissions reductions from forests would be compensated by increased emissions in other biomes. These results suggest that, although REDD + remains a very promising mitigation tool, implementation of complementary measures to reduce land demand is necessary to prevent this leakage.     

Farm-level assessment of CO2 and N2O emissions in Lower Saxony and comparison of implementation potentials for mitigation measures in Germany and England

Greenhouse gases (GHG) emissions from agricultural farming practice contribute significantly to European GHG inventories. For example, CO₂ is emitted when grassland is converted to cropland or when peatlands are drained and cultivated. N₂O emissions result from fertilization. Enabling farmers to reduce their GHG emissions requires sufficient information about its pressure–impact relations as well as incentives, such as regulations and funding, that support climate-friendly agricultural management. This paper discusses potentials to improve the supply of information on: farm-specific climate services or impacts, present policy incentives in Germany and England that support climate-friendly farm management and related adaptation requirements. Tools which have been developed for a farm environmental management software (to be added after review because of potential identification) are presented. These tools assess CO₂ emissions from grassland conversion to cropland and peatland cultivation, as well as N₂O emissions from nitrogen fertilization. As input data, the CO₂ tool requires a classification of soil types according to soil organic carbon storage. The input data based on soil profile samples was compared with reference data from the literature. The N₂O tool relies on farm data concerning fertilization. These tools were tested on three farms in order to determine their viability with respect to the availability of required data and the differentiation of results, which determines how well site-specific conservation measures can be identified. Assessing CO₂ retention function of grassland conservation to cropland on the test farms leads to spatially differentiated results (~100 to ~900 potentially mitigated t CO₂ ha^?1). Assessed N₂O emissions varied from 0.41 to 1.1 t CO₂eq. ha^?1 a^?1. The proposed methods support policies that promote a more differentiated funding of climate conservation measures. Conservation measures and areas can be selected so that they will have the greatest mitigation effects. However, even though present policy instruments in Germany and England, such as Cross Compliance and agri-environmental measures, have the potential to reduce agricultural GHG, they do not appear to guide measures effectively or site-specifically. In order to close this gap, agri-environmental measures with the potential to support climate protection should be spatially optimized. Additionally, the wetland restoration measures which are most effective in reducing GHG emissions should be included in funding schemes.     

崇明岛中长期碳排放预测及其影响因素分析

为更好地推动崇明低碳生态岛的建设,在应用以自下而上的部门法为基础的区域范围温室气体排放评估核算方法,全面核算崇明岛能源消费及温室气体排放现状的基础上,应用LEAP模型,通过情景分析预测崇明岛中长期能源消费需求以及温室气体排放水平,并进一步应用对数平均指数法(LMDI)对影响崇明岛未来温室气体排放的主要因素进行了定量分析。研究表明:参考情景下,崇明岛能源消费总量从2010年的101万吨标煤增加到2050年的533万吨标煤,净碳足迹从2010年的238万吨CO2e增加到2050年的579万吨CO2e。崇明岛能源消费需求和碳排放增加的主要驱动因素是未来的经济发展、人口增长和生活水平的提高,但是通过一系列的优化,尤其是能源结构的变化和能耗强度的下降,减排情景下,崇明岛能源消费总量有可能在2039年左右达到峰值,并有望在2050年左右实现"零碳岛"的长期发展目标。结合定量分析的结论,进一步提出了实现崇明岛低碳发展中长期目标的可能性和重点发展领域。     

Methane and Nitrogen Oxide Fluxes in Tropical Agricultural Soils: Sources, Sinks and Mechanisms

Tropical soils are important sources and sinks of atmospheric methane (CH₄) and major sources of oxides of nitrogen gases, nitrous oxide (NM_2O) and NO_x (NO+NO₂). These gases are present in the atmosphere in trace amounts and are important to atmospheric chemistry and earth's radiative balance. Although nitric oxide (NO) does not directly contribute to the greenhouse effect by absorbing infrared radiation, it contributes to climate forcing through its role in photochemistry of hydroxyl radicals and ozone (O₃) and plays a key role in air quality issues. Agricultural soils are a primary source of anthropogenic trace gas emissions, and the tropics and subtropics contribute greatly, particularly since 51% of world soils are in these climate zones. The soil microbial processes responsible for the production and consumption of CH₄ and production of N-oxides are the same in all parts of the globe, regardless of climate. Because of the ubiquitous nature of the basic enzymatic processes in the soil, the biological processes responsible for the production of NO, N_2O and CH₄, nitrification/denitrification and methanogenesis/methanotropy are discussed in general terms. Soil water content and nutrient availability are key controls for production, consumption and emission of these gases. Intensive studies of CH₄ exchange in rice production systems made during the past decade reveal new insight. At the same time, there have been relatively few measurements of CH₄, N_2O or NO_x fluxes in upland tropical crop production systems. There are even fewer studies in which simultaneous measurements of these gases are reported. Such measurements are necessary for determining total greenhouse gas emission budgets. While intensive agricultural systems are important global sources of N₂O and CH₄ recent studies are revealing that the impact of tropical land use change on trace gas emissions is not as great as first reports suggested. It is becoming apparent that although conversion of forests to grazing lands initially induces higher N-oxide emissions than observed from the primary forest, within a few years emissions of NO and N₂O generally fall below those from the primary forest. On the other hand, CH₄ oxidation is typically greatly reduced and grazing lands may even become net sources in situations where soil compaction from cattle traffic limits gas diffusion. Establishment of tree-based systems following slash-and-burn agriculture enhances N₂O and NO emissions during and immediately following burning. These emissions soon decline to rates similar to those observed in secondary forest while CH₄ consumption rates are slightly reduced. Conversion to intensive cropping systems, on the other hand, results in significant increases in N₂O emissions, a loss of the CH₄ sink, and a substantial increase in the global warming potential compared to the forest and tree-based systems. The increasing intensification of crop production in the tropics, in which N fertilization must increase for many crops to sustain production, will most certainly increase N-oxide emissions. The increase, however, may be on the same order as that expected in temperate crop production, thus smaller than some have predicted. In addition, increased attention to management of fertilizer and water may reduce trace gas emissions and simultaneously increase fertilizer use efficiency.