Coral reef ecological pump for gathering and retaining nutrients and exporting carbon:a review and perspectives

How coral reefs with high productivity and biodiversity can flourish in oligotrophic tropical oceans has inspired substantial research on coral reef ecosystems.Increasing evidence shows that similar to water in an oasis in the desert,there are stable nutrient supplies to coral reefs in oligotrophic oceans.Here,with emphasis on the fluxes of organic matter,we summarize at the ecosystem level(1)the multiple input pathways of external nutrients,(2)the storage of nutrients in reef organisms,(3)the efficient retaining and recycling of dissolved and particulate organic matter within coral reef ecosystems,(4)the distinctly high phytoplankton productivity and biomass inside and near oceanic coral reefs,and(5)the export of reef-related organic carbon to adjacent open oceans.These properties enable coral reefs to function as ecological“pumps”for gathering nutrients across ecosystems and space,retaining and recycling nutrients within the ecosystem,supporting high phytoplankton productivity,and exporting organic carbon to adjacent open oceans.Particularly,the high phytoplankton productivity and biomass make waters around coral reefs potential hotspots of carbon export to ocean depths via the biological pump.We demonstrate that organic carbon influx is vital for coral reef ecosystems’carbon budget and carbon export.The concept of the coral reef ecological pump provides a framework to improve the understanding of the functioning of the coral reef ecosystem and its responses to disturbance.Prospects of the coral reef ecological pump in coral reef studies are discussed in changing oceans driven by human activities and global change in the Anthropocene.

Carbon biomass,production rates and export flux of copepods fecal pellets in the Changjiang(Yangtze) River estuary

Copepod fecal pellets are ubiquitous throughout the oceans. Their production and export can represent a highly efficient pathway of carbon export. However, the role these fecal pellets play in carbon export in the Changjiang(Yangtze) River estuary is not well known. Two cruises were carried out in the Changjiang estuary in the spring and summer of 2013, during which time carbon biomass, production, and export of copepod fecal pellets were studied. Spring and summer fecal pellet carbon biomass ranged 0.30–1.01 mg C/m^3(mean=0.56±0.20 mg C/m^3) and 0.31–1.18 mg C/m^3(mean=0.64±0.24 mg C/m^3), respectively, significantly lower than phytoplankton. At most stations, fecal pellet carbon biomass was higher in surface or subsurface layers than deeper layers. Production rates ranged 0.65–1.49 pellets/(ind.?h)(mean=1.02±0.27 pellets/(ind.?h)) in spring and 0.62–1.34 pellets/(ind.?h)(mean=0.98±0.22 pellets/(ind.?h)) in summer, within the range reported in previous studies. Higher production rates of fecal pellets occurred at stations with higher chlorophyll a concentrations, and production rates of copepods of size 500–1 000 μm greater than copepods >1 000 μm during both cruises. The potential export flux of fecal pellets was slightly higher in summer(mean=68.95±14.37 mg C/(m^2 ?d)) than spring(mean=52.08±11.33 mg C/(m^2 ?d)) owing to higher summer copepod abundances. To our knowledge, this study is the first of its kind in the Changjiang estuary, and it confirms the significant role of copepod fecal pellets in local carbon export.

Empirical analysis of carbon tariff's effect on the export structure of China's manufacturing industry and social welfare based on the GTAP model

In recent years,carbon emissions have gradually evolved from an environment issue into a political and economic one.Carbon tariff has brought about new trade barriers of developed countries,and in order to enhance the industrial competitiveness of developed countries,it will produce unfavorable impact on developing countries.Concentrated on the manufacturing industry,which is the most intensive high-carbon industry in China's export structure,this article studies the relationship between carbon tariff policy and industry structure of export trade and builds up a relation between climate change and international trade.First,by means of establishing a partial equilibrium model,it applies geometric analysis and mathematical analysis to compute the impact on China's manufacturing export trade and the consequences of the introduction of the US carbon tariff to China's manufacturing industry that has already imposed a domestic shipping carbon tax.Furthermore,with the application of the GTAP model,it estimates the overall economic and welfare effects on China's manufacturing industry if the US and Europe introduce carbon tariff by means of four ways,and then analyzes the influence on China's manufacturing industry export structure and social welfare as well.The result shows that the introduction of the US carbon import tariff lowers China's export price and export volume,and the implementation of a domestic carbon tax justifies a higher export price and a lower export volume for China.However,the degree of export reduction is smaller than that under the effect of the US carbon tariff.In the case of developed countries imposing carbon tariff on China's energy-intensive industries,such as chemical rubber products,oil and coal-processing industry and paper industry,whose export would be reduced,the negative impact on the paper industry is the severest,which will decrease the paper industry's export ranging from 1.79%to 6.05%,whereas the other industries' export will increase.Anyhow,it will promote China's manufacturing industry to adjust the export structure to a certain extent.In addition,it will lead to a decrease in China's welfare,with a decrease between $2,134 billion and $8,347 billion.Finally,this paper provides information on international coordination,export structure adjustment and green manufacturing adjustment as a reference for the development of China's manufacturing industry.

ZHANG ZHUYING——A Female Export in Carbon Material Technology

Zhang Zhuying,45,is now chief engineer in No.1 Carbon Plant un-der the Guizhou Aluminum Smelter.Graduated from Central South University of Technology in 1969,shewas assigned to Anode Paste Workshop belong to No.2 Branch under Gui-

Research on carbon emissions in China's export trade based on input-output model

Becoming the world's largest emitter of carbon makes China the object of criticism;however,people may ignore the fact that when China exports low-carbon products,the carbon emissions have been left in the meanwhile,forming the so-called"embodied carbon".Using the input-output model,this paper analyzes the carbon emission intensity and amount of embodied carbon of various sectors in China's export trade in 2002 and 2007,and filters out high carbon emission sectors.In addition,this paper also points out the problem of carbon emissions'international transfer from developed countries to China through the analysis of national and regional flow of export carbon emissions and changing of the proportion of emissions for exports relative to total emissions,and explains the reason that caused carbon transfer to China by using the treadmill of production theory.Based on that,this paper proposes some measures for carbon reduction in China from the foreign trade perspective.

CGE Model Measures Carbon Duty's Impact on China's Exports

Carbon-motivated border tax adjustment is a unilateral international trade policy aimed at compensating for the loss ofcompetitiveness of carbon-intensive products due to carbon dioxide abatement actions.It violates fundamental principlesof the UNFCCC and potentially conflicts with the core WTO principle of non-discrimination as reflected in the GATTArticle Ⅰ and Article Ⅲ.Based on an analysis of carbon emissions embodied in China’s industrial exports,this paperevaluates with a recursive dynamic CGE model the potential impacts of the carbon duty on China’s industrial production,exports and employment.The results of a simulation show that with a tariff rate of US＄30 or US＄60 per ton of carbon,theoutput of China’s industrial sectors would decline by 0.62-1.22 percent,exports by 3.53-6.95 percent,and employment by1.22-2.39 percent.The authors suggest several measures of alleviating the impacts of carbon duty and put forward a carbonduty policy based on carbon consumption per capita as a countermeasure.

Insights into the coupling of upper ocean-benthic carbon dynamics in the western Arctic Ocean from an isotopic(^(13)C, ^(234)Th) perspective

The coupling of upper ocean-benthic carbon dynamics in the ice-free western Arctic Ocean （the Chukchi Sea and the Canada Basin） was evaluated during the late July-early September 2003 using natural stable （13C） and radioactive （238U-234Th） isotope tracers. POC export flux estimated from 234Th/238U disequilibria and dissolved CO2 concentration （[CO2（aq）]） pointed out that the strengthened biological pump in the Chukchi Shelf have significantly lowered [CO2（aq）] and altered the magnitude of isotopic （12C/13C） fractionation during carbon fixation in the surface ocean. Further, δ13C signatures of surface sediments （δ13Csed） are positively correlated to those of weighted δ13Cp0C in upper ocean （δ13Csed =13.64＋1.56xδ13Cpoc, r2=0.73, p〈0.01）, suggesting that the POC isotopic signals from upper ocean have been recorded in the sediments, partly due to the rapid export of particles as evidenced by low residence times of the highly particle-reactive 234Th from the upper water column. It is suggested that there probably exists an upper ocean-benthic coupling of carbon dynamics, which likely assures the sedimentary δ13C record an indicator of paleo-CO2 in the western Arctic Ocean.

Interannual variations of the air-sea carbon dioxide exchange in the different regions of the Pacific Ocean

Interannual variations of the air-sea CO2 exchange from 1965 to 2000 in the Pacific Ocean are studied with a Pacific Ocean model. Two numerical experiments are performed, including the control run that is forced by climatological monthly mean physical data and the climate-change run that is forced by interannually varying monthly mean physical data. Climatological monthly winds are used in both runs to calculate the coefficient of air-sea CO2 exchange. The analysis through the differences between the two runs shows that in the tropical Pacific the variation of export production induced by interannual variations of the physical fields is negatively correlated with that of the air-sea CO2 flux, while there is no correlation or a weak positive correlation in the subtropical North and South Pacific. It indicates that the variation of the physical fields can modulate the variation of the air-sea CO2 flux in converse ways in the tropical Pacific by changing the direct transport and biochemical process. Under the interannually varying monthly mean forcing, the simulated EOF 1 of the air-sea CO2 flux is basically consistent with that of sea surface temperature （SST） in the tropical Pacific, but contrary in the two subtropical Pacific Ocean. The correlation coefficient between the regionally integrated air-sea CO2 flux and area-mean SST shows that when the air-sea CO2 flux lags SST by about 5 months, the positive coefficient in the three regions is largest, indicating that in the tropical Pacific or on the longer time scale in the three regions, physical processes control the fiux-SST relationship.

The energy-intensity of China's export trade

China is one of the world’s major importers and exporters. On the one hand, massive exports have created enormous economic value and employment opportunities for Chinese and become one of the vital forces underpinning the country’s economic growth. On the other hand, exports have caused a huge amount of energy resource consumption and carbon emissions and added pressure to the country for a sustainable growth. China exports a wide variety of products, each of which is attached to a different industry chain with different energy consumptions. Therefore, the evolution of the product structure has become one of the key factors affecting China’s future energy consumption and economic growth. To further promote nationwide energy conservation and emission reduction, reduce the pressure exerted by economic growth on energy consumption and the environment and win more space for sustainable economic growth, it is imperative to understand energy consumption and carbon emissions embodied in export products and provide support for China’s export policy adjustment. This study attempts to calculate, compare and analyze the embodied energy and carbon emissions in 46 major export products using the full life cycle assessment method, and concludes by offering policy recommendations.

中国农产品出口贸易隐含碳排放测算及异质性分析——来自“一带一路”沿线国家(地区)的证据

采用环境拓展投入产出法测算了2007—2021年中国对“一带一路”沿线国家(地区)农产品出口贸易的隐含碳排放,进而运用LMDI模型探究贸易规模因素、出口结构因素和农业技术因素对隐含碳排放变动的贡献值与贡献率,从农产品部门和贸易区域两个层面对隐含碳排放变动的驱动因素进行异质性分析。研究发现:第一,2007—2021年中国对“一带一路”沿线国家(地区)的出口贸易隐含碳排放整体呈上升趋势,农产品出口贸易隐含碳排放年均增长率超过农产品出口贸易额年均增长率2.75%,隐含碳排放效率下降。第二,农产品出口贸易隐含碳排放存在明显的部门差异,因不合理的出口结构,农业、食品制造业和食品加工业等中高度碳排放密集型部门对隐含碳排放总量变动的贡献值占比较大,而林业、畜牧业等低度碳排放密集型部门的这一占比较小。第三,农产品出口贸易隐含碳排放存在明显的区域差异,对东南亚国家(地区)出口农产品产生的隐含碳排放占总碳排放的60%以上,贸易规模因素和农业技术因素是造成区域差异的主导因素。上述发现揭示了中国农产品出口贸易隐含碳排放变动的原因,为优化农产品出口结构、调整农产品出口贸易策略及碳排放双控制度的实施提供了新的思路与经验证据。

广西工业品出口贸易隐含碳变化及其驱动效应研究

文章基于投入产出矩阵GRAS调整方法和投入产出模型对2005—2020年广西工业品出口贸易中的隐含碳进行测算,并利用对数平均迪氏指数分解法(LMDI)分析隐含碳驱动效应。研究发现:广西碳排放总量、工业品出口额和隐含碳排放量整体呈增长趋势,但增速差异明显。2013—2020年,碳排放总量趋于平稳且增速减缓,但工业品出口额及隐含碳排放量增长显著。碳排放总量下降和碳排放系数减小与广西能源消费结构优化有显著关联,但出口规模扩大是隐含碳排放量增长的主要原因,而出口结构、中间投入品排放水平和直接碳排放系数对隐含碳起排放抑制作用。进一步分析发现,规模效应在隐含碳排放中持续发挥促进作用,结构效应和技术效应影响程度次之且呈“U”形作用特点;受产业能耗和科技水平影响,三效应对各部门隐含碳排放变化存在当期关键驱动因素、潜在关键驱动因素的差异,且驱动效用差别显著。基于此,文章提出应积极推进从“能耗双控”向“碳排双控”的制度转变,持续推动重点领域减排降耗,提升全产业链低碳能力;优化能源生产和消费结构,提升能源使用效率;加大技术投入力度,优化产业结构,合理调控部门的规模效应、结构效应和技术效应,推进出口结构升级;综合协调多种政策,加强政策激励及监管等建议。

环境规制视角下出口贸易对碳排放的影响研究——来自我国277个城市的证据

基于我国2006—2019年277个城市的相关数据,利用门槛效应模型,实证检验环境规制对出口贸易碳排放的影响机制和作用机理。研究结果表明:出口贸易对地级以上城市的碳排放存在环境规制的双重门槛效应。但分地区来看,环境规制的门槛效应呈现出“东弱中强”的特征;分时段来看,“低碳城市试点”政策实施后,环境规制的双重门槛效应显著。因此,未来国家应当更加重视优化出口贸易结构,增加技术密集型产品出口占比;此外,合适的环境规制强度才有助于发挥出口贸易的碳减排效应,考虑到东、中、西部地区资源禀赋的不同,各地区应当合理制定环境规制的强度。

欧盟碳边境调节机制对我国出口贸易的影响研究——以对欧盟制造业出口为例

为了深入分析碳关税对我国出口贸易的影响,探索构建碳关税税率对出口影响的定量分析框架,本文运用世界投入产出表(WIOT),以对欧盟贸易为例,借助引力模型计算得出碳排放与出口总额存在较强的相关性,在此基础上证明了碳排放的变化将对中欧贸易产生较大影响。研究表明,随着我国碳排放强度的减小,碳关税对欧盟出口总额的影响减弱,但当碳关税按照70欧元/吨征收时,2019年的出口额仍下降17.91%。此外,11个高碳排放行业的测算结果表明,当碳关税增加到70欧元/吨时,企业出口大幅下降,甚至停止出口。基于实证研究结果,本文提出了加强碳关税政策预判、综合运用收支调节工具、优化外汇政策拓展企业生存空间、进一步推动产业结构转型等政策建议。

中国出口贸易隐含碳的趋势预测及结构转移研究

基于特征选择的Lasso方法分别确定影响中国出口贸易隐含碳排放(CO_(2))总量和强度的核心指标,并由此构建BO-BiLSTM模型对总量变动和强度演进的趋势展开预测,同时采用Markov链进一步探讨中国出口贸易隐含碳排放的结构转移现象。结果表明:(1) 2021—2035年间中国出口贸易隐含碳排放总量呈现阶梯式减少的趋向,预计2030年达到1.98 Gt,在2035年降为1.83 Gt,出口贸易规模扩大和国际经贸形势改善是关键影响因素。(2) 2021—2035年间中国出口贸易隐含碳排放强度保持稳中有降的态势,预计2030年减至0.91 t/万元,相较于2005年减少67%,出口贸易结构变迁和环境规制强度提高是重要驱动因素。(3) 2021—2035年间中国出口贸易隐含碳排放结构仍偏重知识密集型制造业,其存在较大减排潜力,而资本密集型服务业和资本密集型制造业具有减排周期较长的特点。

农产品出口贸易、数字乡村建设与农业碳排放强度

利用2005—2019年30个省份(不含港澳台和西藏)面板数据,在对农业碳排放强度进行测算的基础上,实证分析农产品出口贸易对农业碳排放强度的影响。研究发现:农产品出口贸易对农业碳排放强度有较强的促进作用,总体上提升了农业碳排放强度,表现为正的结构效应、负的规模效应和负的技术效应;地区异质性分析表明,东、中、西与东北四大板块中,只有西部地区农产品出口贸易降低了农业碳排放强度;随着数字乡村建设水平的提升,农产品出口贸易对农业碳排放强度的影响效果逐渐减弱,而后转为抑制。基于此,提出如下建议:优化农产品出口贸易结构;加快农业绿色技术创新和引进;提高数字乡村建设水平。

2023年碳酸二甲酯市场分析及预测

以2019-2023年数据为基础,对我国碳酸二甲酯生产建设、市场供需、价格、进出口贸易等进行分析和预测;指出,国内新上碳酸二甲酯装置的企业,应采用先进成熟技术,并根据市场需求合理分配产品等级,促进企业良性发展。

垂向层化对海洋生物生产和碳沉降影响的模型研究

受到太阳辐射和淡水输入等影响,海洋的次表层和表层将形成温度跃层和盐度跃层。温度和盐度跃层的存在将使得海洋在不同深度上形成明显的层化现象,阻碍上下层水体间的物质交换。为了研究这种不同深度上的层化现象对海洋生态系统垂向结构的影响,使用了一个简化的一维营养盐-浮游植物-碎屑的模型进行研究。结果显示,无论是表层还是次表层的层化,都会显著地抑制层化区域以下水层营养盐的向上输运,导致层化区以上水层内营养盐浓度的降低。同时,层化区域以上水体浮游植物生物量显著降低,次表层浮游植物生物量最大值层(DCM层)变薄,导致真光层内生物生产力降低;而真光层向深海的碳输出通量也同时降低。层化区域越厚、层化越强,真光层内生物生产越受抑制,碳输出通量越低。相比于表层层化,次表层层化的存在则进一步导致DCM层深度加深,并显著降低DCM层的浓度,使得次表层层化造成的真光层内生物生产力和向深海碳沉降降低得更多。研究证明了在全球气候变化造成海洋增温和冰川融化、极端降雨事件增多造成局部海域表层盐度降低的背景下,海洋垂向层化的增强将对海洋生态系统和全球海洋生物地球化学循环产生不可忽视的影响。

“双碳”目标下湖南出口贸易发展路径研究

近年来,湖南省出口贸易发展迅速,但出口产品仍以高碳产品为主,碳排放量较高。“双碳”背景下,本文选取湖南省2005—2021年的数据对碳排放与出口贸易之间的关系进行了实证分析。结果表明,在出口贸易结构方面,一般贸易和加工贸易方式都会对湖南省的碳排放量带来一定的影响,但加工贸易对湖南省的碳排放量影响最大,一般贸易次之。因此,本文提出了优化出口贸易结构、推动无碳能源使用、加强国际合作推广绿色出口等路径,为湖南省出口贸易的的绿色发展提供了参考建议。

中国出口服务贸易数字化水平对“双碳”目标的影响——基于中国与44个国家贸易数据的实证研究

“双碳”目标背景下,数字服务贸易这一新兴贸易形式为控制碳排放提供了新路径。本文根据最新的双边服务贸易数字化数据,选取中国与44个国家2007—2018年的贸易数据,实证检验中国出口服务贸易数字化水平对出口贸易隐含碳的影响。研究可知,中国出口服务贸易数字化水平的提升可以抑制出口隐含碳排放。