Nationally Determined Contributions under the Paris Agreement and the costs of delayed action

Current country-level commitments under the Paris Agreement fall short of putting the world on a required trajectory to stay below a 2°C temperature increase compared to pre-industrial levels by the end of the century. Therefore, the timing of increased ambition is hugely important and as such this paper analyses the impact of both the short and long-term goals of the Paris Agreement on global emissions and economic growth. Using the hybrid TIAM-UCL-MSA model we consider the achievement of a 2°C target against a baseline of the Nationally Determined Contributions (NDCs) while also considering the timing of increased ambition of the NDCs by 2030 and the impacts of cost reductions of key low-carbon technologies. We find that the rate of emissions reduction ambition required between 2030 and 2050 is almost double when the NDCs are achieved but not ratcheted up until 2030, and leads to lower levels of economic growth throughout the rest of the century. However, if action is taken immediately and is accompanied by increasingly rapid low-carbon technology cost reductions, then there is almost no difference in GDP compared to the path suggested by the current NDC commitments.

Key policy insights

• Delaying the additional action needed to achieve the 2°C target until 2030 is shown to require twice the rate of emissions reductions between 2030 and 2050.

• Total cumulative GDP over the century is lower when additional action is delayed to 2030 and therefore has an overall negative impact on the economy, even without including climate change damages.

• Increased ratcheting of the NDC commitments should therefore be undertaken sooner rather than later, starting in conjunction with the 2023 Global Stocktake.

• Early action combined with cost reductions in key renewable energy technologies can reduce GDP losses to minimal levels (<1%).

• A 2°C future with technological advancements is clearly possible for a similar cost as a 3.3°C world without these advances, but with lower damages and losses from climate change.

     

The Background of Regional Lead Isotopic Compositions and Its Application in the Lower and Middle Reaches of the Yangtze River and Neighbouring Areas

The paper systematically deals with the background of regional isotopic compo-sitions in the lower and middle reaches of the Yangtze River and neighbouring areas. It isshown that the lead isotopic compositions of different geological formations and units are con-trolled by the primary mantle heterogeneity, dynamic process of crust-mantle interchange,abundances of uraninm, thorium and lead of various layers of the earth and timing. Studies onthe background of regional isotopic compositions may offer significant information forgeochemical regionalization, tracing of sources of ore-forming materials, and regionalprognosis of ore deposits.     

一次冰雹云过程及其催化试验的数值模拟分析

本文应用中科院大气所建立的三维完全弹性冰雹云模式，对2000年6月9日发生在江苏射阳地区的一次冰雹云过程及其催化试验进行了数值模拟，根据模式输出的高时空分辨率资料，分析了冰雹云发生发展过程中的热力和动力场作用及微物理过程的变化，对这次冰雹云形成的机制作了初步分析，并作了一系列碘化银催化试验，对催化防雹的物理机制又进行了较为深入的探讨。     

峨眉山大火成岩省对四川盆地油气储层的控制作用研究

四川盆地具有演化历史长、沉积盖层厚度大、油气资源丰富等特点,是我国大型含油气盆地之一。上扬子地区中、晚二叠世之间的峨眉山地幔柱活动改变了四川盆地古地理格局,造成地壳的快速抬升,盆地西南地区地壳抬升幅度最大,呈现古剥蚀高地,往北东方向的影响逐渐减弱,从而导致沉积环境自西南向北东由单一的海相依次转变为陆相、海陆过渡相至海相沉积。本文讨论了峨眉山大火成岩省的形成过程及对四川盆地油气储层的影响,认为峨眉山大火成岩省对四川盆地油气储层的影响主要体现在两个阶段、3种影响作用方式。两个阶段是指中二叠世末期和晚二叠世—早三叠世时期。3种方式是指峨眉山地幔柱导致的地壳抬升对下伏中二叠统灰岩储层的改造作用,表现为地幔柱核心区（大理—永仁）中二叠世地层发育风化壳岩溶型储层;峨眉山大火成岩省的火山喷发旋回对火山岩储层的空间发育的控制作用,发育了火山岩储层;峨眉山地幔柱活动控制的晚二叠世盆地构造格架对上覆沉积储层的控制作用,导致了峨眉山地幔柱外围伸展区（川东北—西北）发育海槽,控制了晚二叠世礁滩相沉积的发育等。峨眉山大火成岩省的形成过程不仅形成了优质的火山岩储层,同时也影响了沉积岩相的空间分布、改造了下伏碳酸盐岩的孔隙特征,进而控制了四川盆地的油气储层。     

黄海西朝鲜湾波浪潮流共同作用下二维潮流泥沙数值模拟与砂矿成矿分析

黄海西朝鲜湾是潮流流速特别高、潮流沙脊群发育明显的特殊水动力沉积区，具有砂矿成矿的有利条件。为了分析其成矿特征，论文采用波浪潮流共同作用下的潮流泥沙数值模型，计算模拟了各级波浪潮流作用下的海底冲淤状态和总输沙量，并按形成年代、主要分选控制因素分析了砂矿的成因及漂沙分选方式。结果表明，本区砂矿属于波浪潮流控制型现代滨海区砂矿，其成矿方式为潮流与波浪掀沙、潮流输沙、风暴浪混沙。研究海域类似一个巨型砂矿分选机，分选强度有利于成矿的区域大多为0～20m水深海域，矿层可延续到风爆浪的最大冲刷深度。     

与胡修棉的讨论:水流搬运与沉积过程中掺和作用对碎屑颗粒的重要影响

胡修棉教授(2017)发表的学术论文《物源分析的一个误区: 砂粒在河流搬运过程中的变化》,基于Krumbein滚筒实验结果及大量观察数据,发现现代河流的砂粒中不稳定矿物成分、磨圆度及粒径等变化与国内《沉积岩石学》教材相关结论矛盾,应用于物源分析是“以讹传讹”。受其启发,基于前人研究成果,作者进行了较深入的分析,认为滚筒实验结果对自然界河流砂的机械搬运具有一定的指示意义,即随着搬运距离的增加,颗粒逐渐变细、磨圆度变好,加之河流搬运过程中伴随的化学分解等作用,其中的不稳定成分逐渐变少。但由于掺和作用的存在,河流搬运过程中混合了搬运距离不同的颗粒,其不稳定矿物成分含量、磨圆度和粒径等均会发生变化。国内教材对上述现象均有不同程度的描述,得到广大沉积学者认可,而胡修棉教授(2017)对此论述不够。此外,胡修棉(2017)单从地理位置上划分搬运距离的长短似乎不妥。河流搬运对颗粒的磨圆度和粒径的改造作用缺乏直接的数据证明,建议利用标定法跟踪观察。     

台风"凤凰"强降水过程中的波作用诊断分析

介绍了“扰动热力切变平流参数”的概念,并基于此概念及波流相互作用的理论,对登陆台风“凤凰”2008年7月27日00:00－31日00:00(世界时)的暴雨过程进行了诊断分析.通过采用ARPS模式的资料,对波作用密度M和波作用通量散度▽·F进行计算,分析其与6h累积地面降水的关系.结果表明,波作用密度的异常值区始终覆盖观测雨区,二者在水平分布和时间演变趋势上比较相似,该波作用密度能够比较准确地综合表征强降水系统典型的动力场和热力场扰动的垂直结构,因而与降水系统的发生演变密切相关,其正高值区与观测的6h累积地面降水具有良好的对应关系.同时对波作用通量散度▽·F的分析表明,在登陆台风引发的暴雨过程中,非地转风位涡扰动和一阶扰动平流与动力场和热力场扰动梯度耦合项是影响扰动热力切变平流异常变化的主要强迫项.进一步分析表明扰动与基本态的交换主要是扰动热量平流交换,而扰动动量平流交换非常弱.     

侧移土体被动桩成拱效应分析

在分析某工业厂房坍塌原因的基础上,认为由于侧移土体被动桩的成拱效应,地面超载引起的土压力被传递到桩身上,导致桩身发生了较大的侧向变形是这起事故发生的主要原因,事故的发生证明了侧移土体被动桩成拱效应的存在。在此基础上,建立了三维数值模型,对土拱效应的形成过程进行了模拟。对三维情况下被动桩的成拱效应与相同条件二维情况的形式和变化规律进行了比较,对不同桩间距、不同堆载大小情况下的被动桩成拱效应进行了分析,并对成拱效应随时间的变化规律进行了探讨。     

EFFECT OF ELECTRIC FERTILIZER ON SOIL PROPERTIES

Electric fertilizer, i. e. exerting electric field on plants during growing season instead of chemical fertilizer, is a kind of physical fertilizer, and the third kind of fertilizer with developmental prospect after inorganic fertilizer and organic fertilizer. For the purpose of studying the changes of physical and chemical properties of soil after exerting electric field, five treatments with different applications of chemical fertilizer were arranged on the black soil in Yushu City of Jilin Province by randomized block method, and electric field was exerted on plants every ten days during the growing season. Through sample analysis the paper arrives at following conclusions: 1) Exerting electric field can make soil‘s granular structure increase, bulk density decrease, moisture capacity increase,thus improving the perviousness of soil. 2) Exerting electric field can make microorganism‘s number increase and activity strengthen, thus activating nutrient and increasing organic matter content. 3) Exerting electric field with 0.1A medium has the best effect. So the chemical fertilizer can be saved. Therefore, we can say that the application of electric fertilizer is favorable for decreasing chemical poison, improving soil, relaxing the contradiction between the supply and demand of chemical fertilizer, and decreasing production cost of agriculture and forestry.     

Diagnostic Analysis of Wave Action Density During Heavy Rainfall Caused by Landfalling Typhoon

Based on prior investigation, this work defined a new thermodynamic shear advection parameter, which combines the vertical component of convective vorticity vector, horizontal divergence, and vertical gradient of generalized potential temperature. The interaction between waves and fundamental states was computed for the heavyrainfall event generated by landfalling typhoon“Morakot”. The analysis data was produced by ADAS [ARPS(Advanced Regional Prediction System) Data Analysis System] combined wi...