全球长期城市生态研究中的社会经济要素:指标、数据与应用前景

社会经济要素作为城市生态系统的重要组成部分,能够反映居民特征、衡量居民福祉,是城市生态研究中不可或缺的内容。然而,在城市生态研究中合理、有效利用社会经济要素的规范和框架尚未得到充分研究。城市生态研究中常用的社会经济指标包括哪些？社会经济指标的常见数据源有哪些？社会经济要素可协助回答哪些方面的科学问题？为回答上述问题,本文综述了全球范围内11个长期城市生态研究站点开展的系统性调查和案例研究,总结社会经济指标的内容、数据来源,以及这些研究的议题。结果表明：常用社会经济指标可分为人口基本信息、认知和意愿、行为三类,前两者在城市生态研究中的应用已较为普遍。数据的主要来源包括政府部门提供的统计资料或普查数据、商业数据,以及研究人员开展的独立调查。在城市生态研究中纳入社会经济要素有助于分析社会与环境的相互关系,进而揭示城市系统中人与自然的耦合效应。近年来,我国城市生态研究快速发展,但研究中欠缺对社会经济要素的考虑与利用,可能会逐渐偏离国际上城市生态学的主流研究方向。社会经济数据获取困难是当前研究者面临的重大挑战,同时也存在一些机遇能够促进我国城市生态研究纳入社会经济要素,例如利用新兴数据和大数据手段、构建统一的指标框架和数据共享机制,以及充分了解和利用政府公开的统计数据。     

环杭州湾城市群生态环境与社会经济耦合协调关系及其影响因素

生态环境与社会经济之间的耦合协调关系是可持续发展关注的一个重点和热点。以环杭州湾城市群为研究对象,构建环杭州湾城市群生态环境与社会经济耦合协调度综合评价指标体系,借助ArcGIS软件,采用耦合协调度模型和Pearson相关分析,分析环杭州湾城市群在2000—2019年间生态环境、社会经济发展指数与耦合协调度的演变特征及其影响因素。结果表明：(1)2000—2019年间环杭州湾城市群的社会经济指数呈稳定上升趋势,生态环境指数呈先上下波动后逐年上升的变化趋势;(2)2000—2014年间环杭州湾城市群社会经济的发展速度大于生态环境的发展速度,2015—2019年间生态环境的发展速度大于社会经济发展速度;(3)2000—2019年,环杭州湾城市群生态环境和社会经济之间的耦合协调度从良好协调过度到了完美协调,其中,2000年上海和杭州的耦合协调度小于其它城市,2019年苏州是杭州湾城市群中唯一没有达到完美协调的城市;(4)人口密度、空气质量、工业废水排放量、工业固体废弃物是环杭州湾城市群生态环境与社会经济耦合协调度提高的主要阻碍因素。     

Changing Ruralities: Between Abandonment and Redefinition in the Catalan Pyrenees

In this article we discuss the process by which the upper areas of the Alt Urgell, in Northern Spain, are redefining themselves in order to survive in the new postindustrial order. These communities, during the twentieth century, witnessed a steady demographic and economic collapse that resulted in a progressive decline of agricultural activities and the abandonment of mid-mountain villages. In the sixties, the area deepened its milk production specialisation that offered, for a while, a path towards economic sustainability via connections to national networks of consumption. This solution was severed by the entry of Spain into the European Union. The new European regulations obliterated the industrial production of milk and disconnected the area, once again, from national markets. The early nineties saw these valleys fully engage in a postindustrial economy based on leisure and heritage. This case study allows us to examine how macroeconomic changes that affect rural communities in the Western world redefine the ways in which rural areas engage with larger economic frameworks that, at the end of the day, redefine their identities even as they ensure their viability.     

Valorization of CO2 through lithoautotrophic production of sustainable chemicals in Cupriavidus necator

Coupling recent advancements in genetic engineering of diverse microbes and gas-driven fermentation provides a path towards sustainable commodity chemical production. Cupriavidus necator H16 is a suitable species for this task because it effectively utilizes H₂ and CO₂ and is genetically tractable. Here, we demonstrate the versatility of C. necator for chemical production by engineering it to produce three products from CO₂ under lithotrophic conditions: sucrose, polyhydroxyalkanoates (PHAs), and lipochitooligosaccharides (LCOs). We engineered sucrose production in a co-culture system with heterotrophic growth 30 times that of WT C. necator. We engineered PHA production (20–60% DCW) and selectively altered product composition by combining different thioesterases and phaCs to produce copolymers directly from CO₂. And, we engineered C. necator to convert CO₂ into the LCO, a plant growth enhancer, with titers of ~1.4 mg/L—equivalent to yields in its native source, Bradyrhizobium. We applied the LCOs to germinating seeds as well as corn plants and observed increases in a variety of growth parameters. Taken together, these results expand our understanding of how a gas-utilizing bacteria can promote sustainable production.     

Relationships between milk mid-IR predicted gastro-enteric methane production and the technical and financial performance of commercial dairy herds

Considering economic and environmental issues is important in ensuring the sustainability of dairy farms. The objective of this study was to investigate univariate relationships between lactating dairy cow gastro-enteric methane (CH₄) production predicted from milk mid-IR (MIR) spectra and technico-economic variables by the use of large scale and on-farm data. A total of 525 697 individual CH₄ predictions from milk MIR spectra (MIR-CH₄ (g/day)) of milk samples collected on 206 farms during the Walloon milk recording scheme were used to create a MIR-CH₄ prediction for each herd and year (HYMIR-CH₄). These predictions were merged with dairy herd accounting data. This allowed a simultaneous study of HYMIR-CH₄ and 42 technical and economic variables for 1024 herd and year records from 2007 to 2014. Pearson correlation coefficients (r) were used to assess significant relationships (P<0.05). Low HYMIR-CH₄ was significantly associated with, amongst others, lower fat and protein corrected milk (FPCM) yield (r=0.18), lower milk fat and protein content (r=0.38 and 0.33, respectively), lower quantity of milk produced from forages (r=0.12) and suboptimal reproduction and health performance (e.g. longer calving interval (r=−0.21) and higher culling rate (r=−0.15)). Concerning economic results, low HYMIR-CH₄ was significantly associated with lower gross margin per cow (r=0.19) and per litre FPCM (r=0.09). To conclude, this study suggested that low lactating dairy cow gastro-enteric CH₄ production tended to be associated with more extensive or suboptimal management practices, which could lead to lower profitability. The observed low correlations suggest complex interactions between variables due to the use of on-farm data with large variability in technical and management practices.     

Thermodynamic rarity of electrical and electronic waste: Assessment and policy implications for critical materials

The strategic relevance of extracting raw materials from waste from electrical and electronic equipment (WEEE) in the EU is increasing due to value chain risks caused by geopolitical instability, accessibility of specific minerals, and decreasing reserves due to growing extraction rates. This article examines the quantities of so-called critical raw materials (CRMs) originating within WEEE streams from a depletion perspective. Presently, current recycling targets are based solely on mass collection and recycling rates. We examine the potential limitations of this approach using an exergy-based indicator named thermodynamic rarity. This indicator represents the exergy costs needed for producing materials from the bare rock to market. The case of Italy is used to explore the application of the indicator at the macro (national) and micro (company) level for the product categories “small electronics” and “screens and monitors.” Our estimations show significant differences between the mass and rarity of materials within Italian WEEE streams. While iron accounts for more than 70% of the weight of the product categories analyzed, it accounts for less than 15% of the rarity. Similarly, several CRMs with a small mass have a higher rarity value, for example, tungsten with less than 0.1% of the mass and over 6% of the rarity. The policy context is reflected upon, where it is argued that thermodynamic rarity can provide novel insights to support end-of-life WEEE decision-making processes, for example, target development and recycling standards setting to help prioritize material monitoring and recovery options.     

Economic Custom in a Competitive Marketplace

Dyadic, reciprocal equilibrating relationships, such as trading partnerships in agrarian markets, have been reported from many societies. Data from a competitive marketplace in St. Louis, Missouri is analyzed in a multiple regression to test for the existence of such relationships between merchants and consumers. The interpretation of variables representing each firm's price level and consistency of stock reveals that economic custom is important even in this competitive marketplace.     

Sharing economy rebound: The case of peer-to-peer sharing of food waste

The digital sharing economy is commonly thought to promote sustainable consumption and improve material efficiency through better utilization of existing product stocks. However, the cost savings and convenience of using digital sharing platforms can ultimately stimulate additional demand for products and services. As a result, some or even all of the expected environmental benefits attributed to sharing could be offset, a phenomenon known as the rebound effect. Relying on a unique dataset covering over 750,000 food items shared in the United Kingdom through a free peer-to-peer food-sharing platform, we use econometric modeling, geo-spatial network analysis, and environmentally extended input–output analysis to quantify how much of the expected environmental benefits attributed to sharing are offset via rebound effects under seven re-spending scenarios. We find that rebound effects can offset 59–94% of expected greenhouse gas (GHG) emission reduction, 20–81% of expected water depletion benefits, and 23–90% of land use benefit as platform users re-spent the money saved from food sharing on other goods and services. Our results demonstrate that rebound effects could limit the potential to achieve meaningful reductions in environmental burdens through sharing, and highlight the importance of incorporating rebound effects in environmental assessments of the digital sharing economy.