减少发展中国家毁林排放谈判进展

减少毁林可为减缓大气温室气体浓度上升做出重要贡献,因此减少毁林的议题已被提上气候公约谈判的议事日程（议题6）,将成为今后相当长时间内谈判的重要议题之一。通过调研和分析各缔约方提交的对减少毁林提案的意见及附属科学技术咨询机构（SBSTA）第24届会议的谈判情况,对各国的观点进行了归纳总结和剖析。     

Targeting areas for Reducing Emissions from Deforestation and forest Degradation (REDD+) projects in Tanzania

Reducing Emissions from Deforestation and forest Degradation (REDD+) has gained momentum as a climate mitigation strategy that can be implemented at multiple scales. Sub-nationally, REDD+ projects that aim to capture carbon funding are implemented throughout tropical countries. A spatial targeting approach for optimal REDD+ project landscape is demonstrated using Tanzania as an example. This study used GIS-based Multi-criteria Decision Analysis to identify potential areas for REDD+ projects development incorporating different combinations of criteria. The first approach, efficient targeting, focuses on areas with high forest carbon content, high deforestation risk and low opportunity cost. The second approach, co-benefits targeting, aims at areas with high biodiversity and high poverty rate on top of criteria in efficient targeting. The resulting suitability maps displays areas of high, medium and low suitability for future REDD+ projects development based on the targeting approaches. Locations of current REDD+ projects in Tanzania were also overlaid with suitability map to visually inspect how they match up. This approach allows decision-makers to prioritize preferences for various site-selection criteria and make informed decisions about REDD+ projects locations.     

发展中国家气候灾害及应对能力调查分析

通过一个自主设计的调查问卷的抽样调查,对发展中国家气候灾害的主要状况及开展的应对工作进行了分析,以了解发展中国家的气候灾害及应对能力。调查结果表明,洪涝、干旱和海平面上升是受访发展中国家面临的3种最主要的气候灾害,具有发生频繁、影响范围广且造成损失大的特征。大多数接受调查的发展中国家尚未建立完备的灾害管理体系,加强对气候灾害的监测预警是其应对极端气候事件、降低灾害风险的首要任务之一。帮助其他发展中国家建立并完善监测预警系统应是中国应对气候变化南南合作的重要领域之一。     

秸秆燃烧排放对北京及其周边地区PM2.5浓度影响的数值模拟

采用卫星监测的火点燃烧排放数据,利用区域化学传输模式WRF-Chem模拟分析了2017年5月华北地区细颗粒物(PM2.5)质量浓度分布,通过生物质燃烧排放源(华北区域以秸秆燃烧为主)开关的敏感性试验定量计算了燃烧排放对北京及其周边地区PM2.5质量浓度的影响。卫星监测结果显示,2017年5月华北地区有大量的秸秆焚烧现象,对该地区空气质量造成一定影响的燃烧天数为20 d,占全月总日数的65%左右。数值模拟结果表明:该地区秸秆燃烧排放导致PM2.5浓度升高的区域集中在华北平原农作物产区,其分布位置与卫星监测的火点分布吻合。秸秆燃烧导致这些地区PM2.5浓度月平均值上升幅度普遍超过3 μg/m~3,高值区超过了11 μg/m~3,上升比例可达10%以上;此外,来自华北平原及长三角地区的燃烧排放对北京(特别是东南部地区)污染物浓度的影响是不容忽视的,其中河南、山东、天津等地的秸秆燃烧在合适风场的作用下会严重影响北京,可导致丰台及通州等地PM2.5小时浓度上升超过17 μg/m~3,上升幅度超过40%。     

Effect of temperature on production of CH4 and CO2 from Peat in a Natural and Flooded Boreal Forest Wetland

Flooding of a small boreal forest wetland (979) in northwestern Ontario, caused the formation of peat islands, which resulted in an approximate 10 °C increase in peat temperatures at a depth of 50 cm. Peat collected from the flooded wetland and a natural unflooded wetland was incubated anaerobically at temperatures of 4 °C, 15 °C, and 20 to 25 °C. Flooding of the wetland greatly increased CH4 production rates by increasing the ratio of CH4:CO2 produced from 979 peat (40% : 60%) compared to 632 peat (20% : 80%), at both preflood and postflood temperatures, likely due to the altered hydrological and geochemical conditions within the peat mats due to flooding. CH4 and CO2 production rates approximately tripled for every 10 °C temperature increase and may have been linked to to the metabolic rate of the methanogens or the fermentors independent of the substrate quality. Methane production rates from deep peat deposits within the islands were also significant and responded well to temperature increases despite peat 14C ages of 1000 years. Due to the large quantity of carbon stored within natural wetlands, artificial reservoirs may act as a significant and long term source of CH4 to the atmosphere.