Net primary productivity-based factors of China's carbon intensity: A regional perspective

Reducing carbon intensity (CI) is one of the core steps of climate change mitigation. This study emphasized the roles of ecological services and regional heterogeneity in determining CI. We considered heterogeneities based on geography and income and explored the roles of net primary productivity (NPP)-based carbon footprint and CI in the changes in China's CI over 2001−2015 using an extended production-theoretical decomposition analysis and matching the socio-economic data sets with NPP data from a remote sensing satellite. We found that group technological change, reflecting the effect of shrinkage or expansion of the group best practice frontier, and the potential NPP-based carbon footprint, reflecting the impact of energy-related CO₂ emissions on ecological carbon absorption, are the most significant factors accounting for the increase and decrease in CI, respectively, while NPP-based CI generally accounts for the decline in CI. We further showed that the technology gap change exhibited by an invert U-shaped curve contributed to the increase in CI under geography-based heterogeneity. We advise that China's policies should be more focused on ecological factors and regional heterogeneity in regions with abundant NPP (e.g., Yunnan and Sichuan) to further reduce CI.     

Greenhouse gas implications of replacing fish protein with beef in the lower Mekong Basin

At least 88 new hydropower dams are planned between 2010 and 2030 in the lower Mekong River basin in Southeast Asia as a source of electricity with lower greenhouse gas emissions. Dams result in declines in fish populations that will need to be replaced with other sources of protein for food security. We make the first assessment of emissions should beef production substitute for lost fish in Cambodia and Laos. We assessed two sources of emissions. Replacing lost fish with beef would require as much as 12 million hectares of new pasture. Forest clearing for pastures in Cambodia and Lao PDR would initially emit between 0.859 and 3.015 giga‐tonnes of carbon dioxide equivalents (Gt CO₂‐eq.). Methane emissions from additional cattle would add at least 0.0013 Gt CO₂‐eq./year to Cambodia's total greenhouse gas emissions, equivalent to a 20% increase. In Laos at least 0.0005 Gt CO₂‐eq./year would be released, a 4–12% increase in annual emissions. We demonstrate that activities displaced by hydropower developments could significantly increase emissions. It shows how enclosure of commons at local scales impacts upon other common pool resources at different scales, raising questions for sustainable and equitable transboundary governance.     

干旱地区农田生态系统土壤温室气体排放机制

CO2、CH4和N2O是目前几种最主要的温室气体,在对全球气候变暖贡献中,农业作为重要的温室气体排放源对其有不可低估的作用。一般而言,旱地农田生态系统是大气CO2和N2O的排放源,黄土高原等旱地是CH4的吸收汇。CO2排放主要包括植物呼吸作用和土壤呼吸作用;CH4排放包括有机物的还原和氧化吸收两个过程;N2O排放包括硝化作用和反硝化作用两个过程。土壤微生物、土壤水分、土壤温度、土壤质地、施肥等均从不同角度影响着温室气体的释放与吸收。近些年,免耕、秸秆还田、地膜等保护性耕作技术在干旱地区农田生态系统中得到广泛应用。其中免耕可以减少CO2和N2O的排放量,增加土壤对CH4的吸收量;秸秆还田和覆膜对N2O排放的影响结果尚未统一,但秸秆还田促进CO2排 放抑制CH4吸收,而覆膜促进CH4吸收抑制CO2排放。加强且更深入更全面的研究旱地农田生态系统温室气体排放应该作为今后重点研究领域,为全球气候变暖提供更为准确的理论基础。     

基于低碳经济视角下首都新农村可持续发展的研究

“低碳经济”的概念首先是由英国在《我们未来的能源——创建低碳经济》的白皮书中提出的,其目标是减缓气候变化和促进人类的可持续发展。低碳农业经济能够减少农业排放大量温室气体,应对气候变化对农业的威胁,并实现首都新农村可持续发展。笔者从低碳产业、低碳农业、低碳工业、低碳环境、碳汇减碳五个方面提出低碳农业经济在首都新农村可持续的发展思路。     

Potential futures for road transportation CO2 emissions in the Asia Pacific

Abstract: Will future transportation carbon dioxide (CO₂) emissions per capita in Asia Pacific economies follow historical trends of the now developed world? Evidence to date is inconclusive. A comparison at similar income levels (purchasing power parity) between recent emissions in Asia Pacific countries and historical emissions in developed countries suggests diverging patterns. (A) High‐income Asia economies (Japan, Hong Kong and Singapore –‘low emitters’) exhibit lower emissions than a selected sample of seven developed countries (United States, Australia, France, the Netherlands, Italy, Sweden and United Kingdom). (B) Another set of Asian countries (South Korea and Taiwan –‘medium emitters’) follow the emissions trends of European countries, which are lower than those of Australia and the United States. (C) A third Asian group (Malaysia and Thailand –‘high emitters’) exhibit emission trends comparable to that of Australia. We describe these trends, examine their causes and extrapolate likely futures for emissions in low‐income Asia Pacific economies (China, Indonesia, Philippines and Vietnam). Although such predictions are speculative, the available evidence suggests that road CO₂ emissions for Indonesia, the Philippines and Vietnam will follow those of the third group (high emitters), while those for China may follow either Group B or Group C.     

Vulnerability of lodging risk to elevated CO2 and increased soil temperature differs between rice cultivars

Anthropogenic increases in atmospheric carbon dioxide concentration [CO₂], and subsequent increases in surface temperatures, are likely to impact the growth and yield of cereal crops. One potential means for yield reduction is for climate parameters to increase the occurrence of lodging. Using an in situ free-air CO₂ enrichment (FACE) system, two morphologically distinct rice cultivars, KH (Koshihikari) and SY (Shan you 63), were grown at two [CO₂]s (ambient and ambient + 200 μmol mol⁻¹) and two soil temperatures (ambient and ambient ± 1.8 °C) over a two year period to assess and quantify lodging risk. Elevated [CO₂] per se had no effect on lodging resistance for either cultivar. However, elevated [CO₂] and higher soil temperature increased the lodging risk for SY, due to a relatively higher increase in plant biomass and height at the elevated, relative to the ambient [CO₂] condition. Elevated soil temperature per se also increased lodging risk for both cultivars and was associated with longer internodes in the lower portion of the tillers. These findings illustrate that lodging susceptibility in rice, an important cereal crop, can be increased by rising [CO₂] and soil temperature; however, variation observed here between rice cultivars suggests there may be sufficient intraspecific variability to begin choosing rice lines that minimize the potential risk of lodging.     

Export trade and smog pollution: Empirical evidence from China

This paper examines the impact of China's export trade on smog pollution. Based on provincial panel data from 2006 to 2016 in China, we use spatial econometric methods to empirically investigate the smog pollution effects of China's export trade from two dimensions, export scale and export structure. It has been found that smog pollution in various regions of China has obvious spatial correlation; China's export trade has a significant positive impact on smog pollution, whether in terms of export scale or export structure. After establishing different forms of spatial weight matrices and considering alternative indicators of smog pollution, the results of this paper are still robust.     

生物炭之低碳农业初探

农业生产过程与全球气候变化息息相关,如何减少农业温室气体排放,并探寻土壤固炭方法已经成为当前农业与环境研究中的热点。全文旨在摸索一条由生物质碳化技术为基础的低碳农业发展的可能途径。从低碳这一热点问题出发,本文对低碳农业的定义、特征、途径进行了基本阐述,同时论述了生物炭的基本特征,及生物炭在应用上的农学和环境学价值,并重点讨论了如何利用生物炭发展以低能耗、低排放、低污染为特征的低碳农业的可能模式,最后指出了当前生物炭在低碳农业研究和利用方面所面临的问题和挑战。     

陆地生态系统有机碳储量和碳排放的研究进展

陆地生态系统土壤有机碳储量和土壤呼吸的微小变化,会引起大气CO2浓度的巨大变化以及全球碳循环的明显改变,从而引起全球气候的巨大变化。提高SOC储量、减少土壤CO2排放对减缓大气CO2浓度升高具有重要意义。笔者根据国内外文献数据资料,综合分析陆地生态系统土壤有机碳储量和土壤呼吸的研究进展,并对最近土壤呼吸影响因素的研究热点因子,如土壤温度、土壤水分、大气降水和耕作等进行分析讨论,指出陆地生态系统碳循环研究中应重点加强土壤呼吸的机理、土壤呼吸影响因素、土壤呼吸模型、土壤固碳措施、减排对策的研究。     

低碳农业背景下闽台有机农业交流与发展的研究

摘要：在全球应对气候变暖而提出发展“新的工业革命”--“低碳经济”的背景下,本文在对“低碳经济”兴起和“低碳农业”原理进行阐述的基础上,提出应用“低碳农业”技术,借鉴台湾低碳农业和有机农业的发展经验,以有机农业作为发展福建低碳农业的切入点,以期促进福建有机农业的发展和加强海峡两岸农业经济的合作与交流。     

Response of Growth and Yield of Rice (Oryza sativa) to Elevated Atmospheric Carbon Dioxide in the Subhumid Zone of Sri Lanka

Increasing atmospheric CO₂ is recognized as a major aspect of global climate change that would have a significant impact on the productivity of major agricultural crops. Two field experiments were done, with the objective of quantifying the response of a short‐duration rice (Oryza sativa) variety (BG‐300) to elevated atmospheric carbon dioxide, in the low elevation, subhumid zone of Sri Lanka. The experiment contained three treatments. In the elevated CO₂ treatment, rice was grown at a CO₂ concentration of 570 µmol/mol within open top chambers (OTC s). The ambient CO₂ treatment included crops grown within OTC s, but maintained at the ambient CO₂ concentration of 370 µmol/mol. The third treatment was a crop grown in the open field under ambient CO₂ concentration. Grain yields of rice crops grown under elevated CO₂ were 24 % and 39 % greater than the respective ambient treatments in the maha (January – March 2001) and yala (May – August, 2001) seasons. Significant increases in total biomass at harvest (23 % and 39 %, respectively, in maha and yala) were more responsible for the above yield increases than the slight increases in the harvest index (4 % and 2 %). Yields of the ambient and open field treatments did not differ significantly. Among the yield components, the number of panicles per hill was significantly higher in the elevated treatment and showed significant positive correlations with grain yield in both seasons. In addition, grain yield showed significant positive correlations with the percentage of filled grains in maha and the number of grains per panicle in yala. Significant increases in the number of tillers per hill under elevated CO₂ were responsible for its greater leaf area index and the greater numbers of panicles per hill. Crops under elevated CO₂ accumulated biomass faster than those grown under ambient CO₂ during the vegetative and grain‐filling stages. The results of this study demonstrate that elevated CO₂ causes significant yield increases in rice, even when it is grown in warm, subhumid tropical climates.     

The innovation effect of low-carbon technology transfer from the perspective of carbon emission reduction demand: A case study of the Yangtze River Economic Belt in China

Reducing carbon emissions is the only way to solve the global climate problem, which obviously requires the joint efforts of all regions. From the perspective of carbon emission reduction demand, this research obtains the data of low-carbon patents and CO₂ emissions from 2000 to 2019, and then explores the innovation effect of low-carbon technology transfer in the Yangtze River Economic Belt (YREB). We draw the following conclusions: (1) Low-carbon technology transfer has a positive impact on low-carbon technology innovation. However, a large number of low-carbon technology transfers are concentrated between developed regions in the YREB at present. (2) No matter from the perspective of total amount or efficiency, carbon emission reduction demand can play positive moderating role in the process of exerting the innovation effect of low-carbon technology transfer, indicating that the transfer of low-carbon technologies to regions with high demand is efficient. (3) The moderating effect of carbon emission reduction demand in different regions has regional heterogeneity. Carbon emissions per unit of GDP plays a greater role in moderating the innovation effect of low-carbon technology transfer in the eastern region, while CO₂ emissions plays a greater role in the central and western regions. Therefore, we propose to strengthen the transfer of low-carbon technologies between developed and less-developed regions, and adopt differentiation strategies according to the actual situation of each region. Our research has deepened the understanding of environmental economic geography on the innovation effect of low-carbon technology transfer, and has reference significance for global low-carbon technology cooperation.     

Governing climate change in Hong Kong: Prospects for market mechanisms in the context of emissions trading in China

Hong Kong continues to struggle over which environmental governance approach is in its best interest while fulfilling its environmental obligations. With regard to climate change, Hong Kong's approach is characterised by a passive form of governance that is highly dependent on China's national policy directions. This is reflected, for example, in Hong Kong having not set its own mitigation targets. Market mechanisms have received little attention in developing a city‐wide climate change strategy. A transformative impulse, China's national emissions trading scheme, may provide momentum to a market‐based approach. However, the necessary conditions for such a market mechanism to be successfully implemented in China remain relatively undeveloped. This raises question about early participation by Hong Kong. Direct benefits are likely to be limited, due to Hong Kong's economic structure and weak demand for emissions reduction. Besides, there are regulatory barriers to enforcing emissions targets and/or recognising emissions allowances and credits from China. We therefore argue that nationwide emissions trading may, at this time, present more challenges than opportunities for Hong Kong to leverage its efforts on climate change mitigation. An alternative is to promote voluntary emissions trading that will require active involvement and leadership by businesses.     

中国农田减缓气候变化的潜力与技术途径

以全球变暖为主要特征的气候变化是当前人类面临的主要环境问题之一,并且对农业生产和粮食安全产生了重大影响。增强作物对气候变化的响应与适应能力,提升农田系统固碳减排潜力,是中国农业生产上亟待解决的重要问题。笔者简要分析了国内农业固碳现状,总结了农业生产上应对气候变化的相关技术体系。通过分析国内农业生产适应和减缓气候变化的潜力和技术途径,对未来增加农业固碳潜力的研究做出了展望,为气候变化背景下实现中国农业的可持续发展提供了新的参考和借鉴。     

The relevance of N fertilization for the amount of total greenhouse gas emissions in sugar beet cultivation

The agricultural sector is highly affected by climate change and it is a source of greenhouse gases. Therefore it is in charge to reduce emissions. For a development of reduction strategies, origins of emissions have to be known. On the example of sugar beet, this study identifies the main sources and gives an overview of the variety of production systems. With data from farm surveys, calculations of greenhouse gas (GHG) emissions in sugar beet cultivation in Germany are presented. Emissions due to the production and use of fertilizers and pesticides, emissions due to tillage as well as field emissions were taken into account. All emissions related to the growing of catch crops during fall before the cultivation of sugar beet were also included. The emissions are related to the yield to express intensity.The median of total GHG emissions of sugar beet cultivation in Germany for the years 2010–2012 amounted to 2626 equivalents of CO₂ (CO₂eq) kg ha⁻¹ year⁻¹ when applying mineral plus organic fertilizer and to 1782 kg ha⁻¹ when only organic fertilizer was applied. The CO₂eq emissions resulting from N fertilization exclusively were 2.5 times higher than those caused by diesel and further production factors. The absence of emissions for the production of organic fertilizers led to 12% less total CO₂eq emissions compared to the use of mineral fertilizer only. But by applying organic fertilizer only, there were more emissions via the use of diesel due to larger volumes transported (126 l diesel ha⁻¹ vs. 116 l ha⁻¹ by applying mineral fertilizer exclusively).As there exists no official agreement about calculating CO₂eq emissions in crop production yet, the authors conclude that there is still need for further research and development with the aim to improve crop cultivation and crop rotations concerning GHG emissions and the therewith related intensity.     

充分发挥茶园碳汇功能，促进茶叶低碳生产发展

在全球气候变化已引起世界各国关注的今天,发展低碳经济,采用可持续的低碳农业技术措施发展低碳农业,是解决气候变化与经济发展矛盾的有效途径。本研究介绍了茶园碳汇功能：茶树生长对空气中CO2的固定和茶园土壤碳库对有机碳的富积和保存。总结中国茶叶生产实践和茶叶科学研究过程中形成的低碳茶叶生产技术：因地制宜合理规划、合理开垦防止烧山垦园、合理密植因缺补缺、平衡施肥促进茶树无机有机物质循环过程的进程、立体栽培增加茶园生物多样性、免耕或减耕减少土壤碳排放、增施有机肥提高土壤C/N率等;提出提高茶农对低碳的认识、建立茶叶低碳生产示范园区、加强对茶叶生产低碳技术的研究、大力发展有机茶、政府政策导向支持等促进茶叶低碳生产发展建议。采用低碳生产技术,挖掘茶园生态系统的碳汇能力,增加茶园系统碳储量,必将对减少温室气体排放做出重大贡献。     

我国农产品出口现状及竞争力分析

【目的】随着自由贸易区战略的实施,中国的农产品出口将获得良好的发展机遇,但国内农产品市场开放的压力也将不断增加。在这种情况下,如何扬长避短、提升我国农产品的出口竞争力、最大化农产品贸易收益就变得尤为重要。【方法】从中国的农产品贸易平衡状况、农产品出口区域以及出口主体出发,分析了中国的农产品出口现状,并在此基础上,采用国际市场占有率(IMS)、显示性比较优势指数(RCA)和出口竞争力系数(CI)3个指标对我国农产品的出口竞争力进行了测算和分析。【结果】结果表明,我国的农产品总体出口竞争力相对较弱,仍需进一步提升。【结论】我国应该采取调整农业产业结构、提升农产品附加值、增强品牌效应、积极开发新兴市场等措施来进一步增强我国农产品的出口竞争力。     

Perforation-mediated modified atmosphere packaging: Part I. Development of a mathematical model

A space-and-time dependent mathematical model describing perforation-mediated modified atmosphere packages was developed for respiring commodities. The model is based primarily on fundamental laws, with empirical relations used only when no other approach can be devised or when there is a significant advantage from using an empirical approach. The computational domain is divided into four subdomains: a part of the ambient storage environment; the perforation, allowing gas exchange between the package and the ambient; the commodity layer, inside the package; and the headspace above the commodity, but also contained in the package. The package walls are rigid and impermeable to gases but heat conducting. The commodity is treated as a homogenous porous medium with distributed sinks for oxygen consumption and distributed sources for carbon dioxide production due to commodity respiration. The commodity model also accounts for water vapour production due to transpiration and removal caused by possible condensation. The effects of commodity temperature and headspace gas composition on oxygen consumption and carbon dioxide production are accounted through a respiration model. The model permits the determination of the gas mixture velocity as the solution of Darcy's law in the commodity layer and the Navier–Stokes equations in the headspace, perforation, and surrounding ambient storage area. Transport of oxygen, carbon dioxide, water vapour and nitrogen is modelled based on Maxwell–Stefan equations coupled with the Navier–Stokes equations and Darcy's law. Solubility of carbon dioxide within the commodity has been included in the model. Commodity temperature and gas mixture temperature are modelled as solutions of the energy equation in the appropriate subdomains, coupled through transpiration, condensation, and convective heat transfer at the commodity surface.     

Trading in waste: Integrating sustainable development goals and environmental policies in trade negotiations toward enhanced solid waste management in Pacific Islands countries and territories

This paper provides a broad survey of existing literature on contemporary solid waste management (SWM) in the Pacific region to underscore an urgent and compelling need for improved SWM. Despite advances in waste management systems and funding for technical support and capacity building from a range of sources, waste continues to threaten public and ecological health and the economy in Pacific Islands Countries and Territories (PICTs). SWM in the Pacific requires innovative thinking in a challenging environment of remoteness, limited available land, fragile ecosystems, vulnerability to natural hazards and subsequent climate sensitivity. Many PICTs are under considerable pressure to open their markets up to trade liberalisation. Increasing links to the global economy through trade liberalisation could either further exacerbate waste management challenges in the Pacific or contribute to environmental protection and sustainable development goals. The authors argue that if the PICTs' urgent waste management challenges are to be meaningfully addressed, the region's leaders must ensure trading partners conform to local environmental protection policies and that trade agreements align with sustainable development goals.     

Elevated [CO2] and warming increase the macronutrient use efficiency and biomass of Stylosanthes capitata Vogel under field conditions

Stylosanthes capitata Vogel is a C3 forage legume widely cultivated in tropical and subtropical pastures. However, the nutrient dynamics of this species under future climate change is unknown. Therefore, this study aimed to evaluate the nutrient content, nutrient accumulation, nutrient use efficiency and growth of S. capitata exposed to increased [CO₂] and temperature under field conditions using two levels of atmospheric [CO₂] (ambient and elevated—600 ppm) and two canopy temperature (ambient and elevated—2°C). Treatments were applied at field conditions, for 30 days, using a free-air carbon dioxide enrichment (FACE) and a free-air temperature-controlled enhancement (T-FACE) systems. Warming showed no effects on macronutrient content, but increased the accumulation of nitrogen, potassium, calcium, magnesium and sulphur, the nutrient use efficiency and root dry mass. Elevated [CO₂] alone had no effect on most of the parameters evaluated. However, the combination of elevated [CO₂] with warming improved the nutrient accumulation, nutrient use efficiency and whole-plant growth more than under isolated conditions of elevated [CO₂] or warming. Based on our short-term results, we concluded that an increment of atmospheric [CO₂] and temperature will benefit S. capitata growth, suggesting no alterations in the actual fertilizer programs for this species.