Methane and nitrous oxide fluxes from four tundra ecotopes in Ny-Ålesund of the High Arctic

During the summers of 2008 and 2009, net methane（CH4） and nitrous oxide（N2O） fluxes were investigated from 4 tundra ecotopes： normal lowland tundra（LT）, bird sanctuary tundra（BT）, the tundra in an abandoned coal mine（CT） and the tundra in scientific bases（ST） in Ny-Alesund of the High Arctic. Tundra soils in CT（184.5 ± 40.0 μg CH4/（m2·hr）） and ST（367.6 ± 92.3 μg CH4/（m2·hr）） showed high CH4 emissions due to the effects of human activities, whereas high CH4 uptake or low emission occurred in the soils of LT and BT.The lowland tundra soils（mean,-4.4-4.3 μg N2O/（m2·hr）） were weak N2 O sources and even sinks. Bird activity increased N2 O emissions from BT with the mean flux of7.9 μg N2O/（m2·hr）. The mean N2 O fluxes from CT（45.4 ± 10.2 μg N2O/（m2·hr）） and ST（78.8 ± 18.5 μg N2O/（m2·hr）） were one order of magnitude higher than those from LT and BT, indicating that human activities significantly increased N2 O emissions from tundra soils. Soil total carbon and water regime were important factors affecting CH4 fluxes from tundra soils. The N2 O fluxes showed a significant positive correlation with ammonia nitrogen（NH4＋-N） contents（r = 0.66, p 〈 0.001） at all the observation sites, indicating that ammonia nitrogen（NH4＋-N） content acted as a strong predictor for N2 O emissions from tundra soils. The CH4 and N2O fluxes did not correspond to the temperature variations of soil at 0-15 cm depths.Overall our results implied that human activities might have greater effects on soil CH4 and N2O emissions than current climate warming in Ny-Alesund, High Arctic.     

武汉市废弃物处理温室气体排放和控制对策

对武汉市2005、2010和2012年废弃物处理温室气体排放量进行了核算,结果表明2005、2010和2012年废弃物处理中生活垃圾填埋和废弃物焚烧产生的温室气体量最大,占折算为碳含量后的71.46%以上,是武汉市废弃物处理温室气体排放的重要来源。填埋产生的温室气体在2010年达到峰值,因填埋量减少、焚烧量增加导致焚烧产生的温室气体量增加。废水处理中温室气体的量相对较小,产生甲烷(CH_4)约0.44至0.67万t。废水处理中温室气体排放量随着污水收集率逐步提高而降低,而又随污水总量增加而增加。总体来说,废弃物处理中二氧化碳(CO_2)排放量逐年增加,CH_4先增加后降低,氧化亚氮(N_2O)逐年增加。此外,武汉市固体废弃物处理温室气体排放主要控制填埋量和焚烧量,而加强废弃物的收集和管理,以及技术提升、生态修复、增加植被碳汇将是武汉市废弃物处理温室气体控制和减排的重要措施。     

油气挥发污染控制技术探讨

油品储运过程中油气的挥发带来了严重的环境污染。利用油气回收技术作为主要的降耗措施已得到重视和推广应用。通过对储运过程中污染现状的分析及各类油气回收控制技术特点的分析,为今后的技术开发指出方向。     

COD监测技术及其方法的发展

现在测定COD多数采用的是重铬酸钾硫酸回流法消解水样,此方法存在着消解后铬盐排放会造成二次污染、回流氧化时间过长、因使用剧毒的汞盐作掩蔽剂易引起汞污染等缺点。针对这些缺点本文将介绍一些新的方法和监测技术。     

Carbon benefits from Amazonian forest reserves: leakage accounting and the value of time

Amazonian forest reserves have significant carbon benefits, but the methodology used for accounting for these benefits will be critical in determining whether the powerful economic force represented by mitigation efforts to slow global warming will be applied to creating these reserves. Opportunities for reserve creation are quickly being lost as new areas are opened to deforestation though highway construction and other developments. Leakage, or the effects that a reserve or other mitigation project provokes outside of the project boundaries, is critical to a proper accounting of net carbon benefits. Protected areas in the Amazon have particularly great potential mitigation benefits over an extended time horizon. Over a 100-year time frame, virtually no unprotected forest is likely to remain, meaning that potential leakages (both leakage to the vicinity of the reserves and that displaced by removing protected areas from the land-grabbing market) should not matter much because any short-term leakage would be “recovered” eventually. The effect of the value attributed to time greatly influences the impact of leakage on benefits credited to reserves. Simple assumptions regarding leakage scenarios illustrate the benefits of reserves and the critical areas where agreement is necessary to make this option a practical component of mitigation efforts. The stakes are too high to allow further delays in reaching agreement on these issues.     

On the value of temporary carbon: a comment on Kirschbaum

A recent paper by Miko Kirschbaum (Mitigat Adapt Strategies Glob Change 11(5–6):1151–1164, 2006) argues that temporary carbon (C) storage has “virtually no climate-change mitigation value.” However, temporary carbon has value in delaying global warming that needs to be recognized in carbon accounting methodologies. The conclusions reached are very sensitive to any value that is attached to time. Basing analysis exclusively on the maximum temperature reached within a 100-year time frame ignores other important impacts of global warming that also need to be included when mitigation strategies are assessed. The relative weightings for long-term versus short-term impacts represent policy choices that result in a greater or a lesser value being attributed to temporary carbon, but that value should not be zero. Global warming is too formidable an enemy to allow us the luxury of discarding part of our arsenal in fighting against it. Both reducing fossil-fuel combustion and increasing biosphere carbon stocks are needed.     

Industrial symbiosis contributing to more sustainable energy use - an example from the forest industry in Kymenlaakso, Finland

Industrial symbiosis (IS) studies the physical flows of materials and energy in local industrial systems using a systems approach. In this study the total fuel and energy use, and greenhouse gas emissions are calculated for an ‘industrial park’ operating in the same manner as an IS. Moreover the relevance of industrial symbiosis, particularly one centred on pulp and paper manufacturing, in moving towards more sustainable fuel consumption and reduced greenhouse gas emissions is discussed. The system is compared to hypothetical stand-alone production. Moreover, possibilities to reduce the energy use and total greenhouse gas emissions of the park are identified.     

适应气候变化是当务之急

地球气候变化既有自然因素又有人为因素,全球变暖主要原因是人类活动温室气体排放过度。因此,在应对气候变化问题上,人们对减排温室气体高度重视是理所当然,而长期以来对“适应气候变化”却有所忽视。其实,对发展中国家《适应气候变化》才是当务之急。文章在前文“发展低碳经济,应对全球变暖”减排二氧化碳温室气体的基础上,论述适应气候变化的迫切性和基本途径。     

Soil management practices for sustainable agro-ecosystems

A doubling of the global food demand projected for the next 50 years poses a huge challenge for the sustainability of both food production and global and local environments. Today’s agricultural technologies may be increasing productivity to meet world food demand, but they may also be threatening agricultural ecosystems. For the global environment, agricultural systems provide both sources and sinks of greenhouse gases (GHGs), which include carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). This paper addresses the importance of soil organic carbon (SOC) for agro-ecosystems and GHG uptake and emission in agriculture, especially SOC changes associated with soil management. Soil management strategies have great potential to contribute to carbon sequestration, since the carbon sink capacity of the world’s agricultural and degraded soil is 50–66% of the historic carbon loss of 42–72 Pg (1 Pg=10¹⁵ g), although the actual carbon storage in cultivated soil may be smaller if climate changes lead to increasing mineralization. The importance of SOC in agricultural soil is, however, not controversial, as SOC helps to sustain soil fertility and conserve soil and water quality, and organic carbon compounds play a variety of roles in the nutrient, water, and biological cycles. No-tillage practices, cover crop management, and manure application are recommended to enhance SOC storage and to contribute to sustainable food production, which also improves soil quality. SOC sequestration could be increased at the expense of increasing the amount of non-CO₂ GHG emissions; however, soil testing, synchronized fertilization techniques, and optimum water control for flooding paddy fields, among other things, can reduce these emissions. Since increasing SOC may also be able to mitigate some local environmental problems, it will be necessary to have integrated soil management practices that are compatible with increasing SOM management and controlling soil residual nutrients. Cover crops would be a critical tool for sustainable soil management because they can scavenge soil residual nitrogen and their ecological functions can be utilized to establish an optimal nitrogen cycle. In addition to developing soil management strategies for sustainable agro-ecosystems, some political and social approaches will be needed, based on a common understanding that soil and agro-ecosystems are essential for a sustainable society.     

Pollution characteristics of 15 gas- and particle-phase phthalates in indoor and outdoor air in Hangzhou

Phthalate esters (PAEs), typical pollutants widely used as plasticizers, are ubiquitous in various indoor and outdoor environments. PAEs exist in both gas and particle phases, posing risks to human health. In the present study, we chose four typical kinds of indoor and outdoor environments with the longest average human residence times to assess the human exposure in Hangzhou, including newly decorated residences, ordinary residences, offices and outdoor air. In order to analyze the pollution levels and characteristics of 15 gas- and particle-phase PAEs in indoor and outdoor environments, air and particulate samples were collected simultaneously. The total PAEs concentrations in the four types of environments were 25,396, 25,466.8, 15,388.8 and 3616.2?ng/m³, respectively. DEHP and DEP were the most abundant, and DMPP was at the lowest level. Distinct variations in the distributions of indoor/outdoor, gas/particle-phase and different molecular weights of PAEs were observed, showing that indoor environments were the main sources of PAEs pollution. While most PAEs tended to exsit in indoor sites and gas-phase, the high-molecular-weight chemicals tended to exist in the particle-phase and were mainly found in PM_2.5. PAEs were more likely adsorbed by small particles, especially for the indoor environments. There existed a good correlation between the particle matter concentrations and the PAEs levels. In addition, neither temperature nor humidity had obvious effects on the distributions of the PAEs concentrations.