• Energy Research

The resilience of cities in response to natural disasters and long-term climate change has emerged as a focus of academic and policy attention. In particular, how to understand the interconnectedness of urban and natural systems is a key issue. This paper introduces an urban model that can be used to evaluate city resilience outcomes under different policy scenarios. The model is the Wellington Integrated Land Use-Transport-Environment Model (WILUTE). It considers the city (i.e., Wellington) as a complex system characterized by interactions between a variety of internal urban processes (social, economic and physical) and the natural environment. It is focused on exploring the dynamic relations between human activities (the geographic distribution of housing and employment, infrastructure layout, traffic flows and energy consumption), environmental effects (carbon emissions, influences on local natural and ecological systems) and potential natural disasters (e.g., inundation due to sea level rise and storm events) faced under different policy scenarios. The model gives insights that are potentially useful for policy to enhance the city’s resilience, by modelling outcomes, such as the potential for reduction in transportation energy use, and changes in the vulnerability of the city’s housing stock and transport system to sea level rise.

The past decades have witnessed a number of informal land developments on the urban fringe in China although many strict state regulations have been made to control this. The dual urban rural land system is widely believed to be one major determinant of informal developments in the existing literature. However, the important role of local villages and townships are often neglected. This paper aims to shed light on this by looking at the gated informal housing communities in Beijing as a case study. It investigates the role of villages and townships in informal land development and the conflicts of interest that arise with state regulations in the context of political decentralization. The results of analysis show that township governments have an ambivalent attitude or even give tacit approval to informal land development in villages since these informal developments actually bring economic benefits to local villagers and themselves. The situation seems to be worse as townships have poor fiscal capacity and a growing administrative responsibility for improvement of local development in the context of decentralization. Villages are keen to capture economic benefits from informal land development with help from private developers. As a result, a local, informal coalition between townships, villages, and private developers emerged at the grass roots level. This presents a major challenge to the state regulations designed for sustainable urban growth management.

Vegetation is crucial in enhancing the urban environment and benefiting human settlements. Consequently, monitoring and attributing vegetation dynamics in urban agglomerations are paramount. Nevertheless, quantitatively assessing the driving mechanisms of urban vegetation proves challenging due to its direct regulation by human land use activities and its susceptibility to influences from urban environmental changes intertwined with global environmental shifts. A critical obstacle arises from the scarcity of reliable long-term observation data, further amplifying the difficulty of such research. Using a newly developed technique that effectively resolves cross-sensor bias and low revisiting frequency issues, we generated Landsat-based long-term vegetation indices data (NDVI, EVI, and NIRv) during 1986–2020. Our study quantified spatiotemporal vegetation changes and examined the contributions of various drivers, including atmospheric CO2 concentration, climate variations, and land cover changes over the past four decades in two representative urban agglomerations in China: the Wuhan Metropolitan Area (WMA) and the Guangdong-Hong Kong-Macao Greater Bay Area (GBA). We found notable and prevalent rising trends of vegetation growth in WMA and GBA during 1986–2020, with considerable spatial and time-period variability. Greening was continuously observed in WMA with a significant increasing trend (0.0019 yr−1, p < 0.01) in annual EVImax, while in GBA, the trends shifted from slightly decreasing (-0.0003 yr−1, p < 0.01) before 2000 to increasing (0.0038 yr−1, p < 0.01) after 2000. The disparities between WMA and GBA were due to urban development status variations across cities and periods. Elevated CO2 concentration and increased solar radiation were the primary factors behind the overall greening. However, land cover changes partially offset these positive contributions in WMA. Our results assist in understanding vegetation dynamics and the effects of climatic and anthropogenic factors at the urban scale, providing valuable insights for ecological management in metropolitan areas.

Abstract The threat of global climate change has caused the international community to pay close attention to atmospheric levels of greenhouse gases such as carbon dioxide. Transportation sector carbon dioxide emissions efficiency (TSCDEE) is a key indicator used to prioritize sustainable development in the transportation sector. In this paper, the epsilon-based measure data envelopment analysis model with undesirable outputs is applied to estimate TSCDEE for 30 provinces in China from 2010 to 2016. We also analyze influencing factors using the spatial Durbin model. Research shows that the overall TSCDEE of the Chinese provinces studied was 0.618, indicating that most regions are still in need of improvements. The provinces with the highest TSCDEE are located in developed coastal regions of China. This study shows that factors such as transportation structure, traffic infrastructure level, and technological progress have prominent positive effects on TSCDEE, while both urbanization level and urban population density exert significantly negative effects on TSCDEE. The findings should have a far-reaching impact on the sustainable development of global transportation.

Anthropogenic land greening is a vital strategy to combat the global warming crisis. However, the changing external environment and endowment factors may constrain the effectiveness of land greening. It remains unclear how to quantify and optimize land greening strategies scientifically. This article reviewed the theoretical foundations of land greening, pointing out that climate governance and human settlement quality improvement have gradually become the two core objectives of land greening since the 20th century. Multi-source and multi-scale experimental and observational surveys are important techniques for detecting and evaluating long-term land greening in the context of climate change, especially by forming experimental and observational networks. The theoretical mechanisms of interactions among climate, humans, and vegetation were also explored. For modeling approaches, hybrid modeling based on Earth system coupling theory may be the most promising but challenging approach. Four main challenges of scientific land greening were also discussed, including knowledge gaps related to land greening mechanisms, unclear multifaceted effects of land greening, lack of forward-looking quantitative assessment, and difficulties in evaluating synergies and trade-offs among assessment targets. Based on these, a strategic framework was proposed, including systematic observation, mechanism research, expectation assessment, and scientific planning for scientific greening programs in the Guangdong–Hong Kong–Macao Greater Bay Area. This review underscored the importance of proactively implementing land greening programs and provided guidelines for scientific greening based on cutting-edge theory and methods.

En este artículo, discutimos la idea de reutilizar las baterías de los vehículos eléctricos para almacenar energía solar para lograr la disponibilidad constante de energía solar en la red eléctrica. En primer lugar, discutimos el esquema de reutilización de baterías de vehículos eléctricos para almacenar energía solar. A continuación, una descripción general de la situación mundial de la energía solar y las ventas de vehículos eléctricos. Con base en dicha información, además operamos una simulación simple sobre el potencial de las baterías de EV reutilizadas para el almacenamiento de energía solar. Encontramos un gran potencial en la mayoría de los países líderes del mundo. Más de la mitad de los países y regiones simulados tienen suficientes baterías de EV reutilizadas para almacenar su propia energía solar generada y alimentar la red antes de 2050, incluida la Unión Europea, China y EE. UU. Finalmente, discutimos los desafíos futuros y las barreras de la realización de la idea. Las dificultades surgen desde la perspectiva del marco integral y el estándar para la prueba de baterías reutilizadas, el seguro de seguridad, el valor económico en comparación con la producción de baterías nuevas y los blancos de las regulaciones y la legislación del mercado en la mayoría de los países. Dans cet article, nous discutons de l'idée de réutiliser les batteries de VE pour stocker l'énergie solaire afin de réaliser la disponibilité constante de l'énergie solaire dans le réseau électrique. Tout d'abord, nous discutons du schéma de réutilisation des batteries de VE pour le stockage de l'énergie solaire. Ensuite, un aperçu de la situation mondiale de l'énergie solaire et des ventes de VE. Sur la base de ces informations, nous procédons en outre à une simulation simple du potentiel des batteries de VE réutilisées pour le stockage de l'énergie solaire. Nous avons trouvé de grands potentiels dans la plupart des principaux pays du monde. Plus de la moitié des pays et régions simulés ont suffisamment de batteries de VE réutilisées potentielles pour stocker leur propre énergie solaire générée et alimenter le réseau avant 2050, y compris l'Union européenne, la Chine et les États-Unis. Enfin, nous discutons des défis futurs et des obstacles à la réalisation de l'idée. Les difficultés émergent du point de vue d'un cadre et d'une norme complets pour le test des batteries réutilisées, de l'assurance sécurité, de la valeur économique par rapport à la production de batteries neuves et des lacunes de la réglementation et de la législation du marché dans la plupart des pays. In this article, we discuss the idea of repurposing EV batteries for storing solar energy to realize the constant availability of solar energy in power grid. Firstly, we discuss the scheme of reusing EV batteries for storing solar energy. Then, an overview of the global solar energy and EV sales situation. Based on such information, we furtherly operation a simple simulation on the potential of reused EV batteries for solar energy storage. We found great potentials in most of world leading countries. Over half of simulated countries and regions have enough potential reused EV battries for storing their own generated solar energy and power the grid before 2050, including European Union, China and USA. Finally, we discuss the future challenges and barriers of realizing the idea. The difficulties emerge from the perspective of comprehensive framework and standard for reused battery test, Safety insurance, Economic value compared with new battery production and Blanks of market regulations and legislation in most countries. في هذه المقالة، نناقش فكرة إعادة استخدام بطاريات السيارات الكهربائية لتخزين الطاقة الشمسية لتحقيق التوافر المستمر للطاقة الشمسية في شبكة الطاقة. أولاً، نناقش مخطط إعادة استخدام بطاريات السيارات الكهربائية لتخزين الطاقة الشمسية. ثم، نظرة عامة على الوضع العالمي لمبيعات الطاقة الشمسية والسيارات الكهربائية. بناءً على هذه المعلومات، نقوم أيضًا بتشغيل محاكاة بسيطة حول إمكانات بطاريات السيارات الكهربائية المعاد استخدامها لتخزين الطاقة الشمسية. وجدنا إمكانات كبيرة في معظم البلدان الرائدة في العالم. أكثر من نصف البلدان والمناطق المحاكاة لديها ما يكفي من معارك المركبات الكهربائية المحتملة المعاد استخدامها لتخزين الطاقة الشمسية المولدة الخاصة بها وتشغيل الشبكة قبل عام 2050، بما في ذلك الاتحاد الأوروبي والصين والولايات المتحدة الأمريكية. وأخيرًا، نناقش التحديات والعوائق المستقبلية التي تحول دون تحقيق الفكرة. تنشأ الصعوبات من منظور الإطار والمعيار الشاملين لاختبار البطاريات المعاد استخدامها، وتأمين السلامة، والقيمة الاقتصادية مقارنة بإنتاج البطاريات الجديدة وفراغات لوائح وتشريعات السوق في معظم البلدان.

Les événements climatiques extrêmes constituent un risque majeur pour la production alimentaire mondiale. Parmi ceux-ci, les précipitations extrêmes sont souvent écartées des analyses historiques et des projections futures, dont les impacts et les mécanismes restent mal compris. Ici, nous avons utilisé des observations à long terme à l'échelle nationale et des expériences de manipulation des précipitations à plusieurs niveaux pour explorer l'ampleur et les mécanismes des impacts des précipitations extrêmes sur le rendement du riz en Chine. Nous constatons que les réductions de rendement du riz dues aux précipitations extrêmes étaient comparables à celles induites par la chaleur extrême au cours des deux dernières décennies, atteignant 7,6 ± 0,9% (une erreur type) selon les observations à l'échelle nationale et 8,1 ± 1,1% selon le modèle de culture intégrant les mécanismes révélés par les expériences de manipulation. Les précipitations extrêmes réduisent le rendement du riz principalement en limitant la disponibilité de l'azote pour le travail du sol, ce qui réduit les panicules efficaces par zone, et en perturbant physiquement la pollinisation, ce qui diminue les grains remplis par panique. Compte tenu de ces mécanismes, nous prévoyons une réduction supplémentaire du rendement d'environ8% en raison des précipitations extrêmes sous un climat plus chaud d'ici la fin du siècle. Ces résultats démontrent qu'il est essentiel de tenir compte des précipitations extrêmes dans les évaluations de la sécurité alimentaire. Los fenómenos climáticos extremos constituyen un riesgo importante para la producción mundial de alimentos. Entre estos, las precipitaciones extremas a menudo se descartan de los análisis históricos y las proyecciones futuras, cuyos impactos y mecanismos siguen siendo poco conocidos. Aquí utilizamos observaciones a largo plazo a nivel nacional y experimentos de manipulación de lluvias multinivel para explorar la magnitud y los mecanismos de los impactos extremos de las lluvias en el rendimiento del arroz en China. Encontramos que las reducciones del rendimiento del arroz debido a las precipitaciones extremas fueron comparables a las inducidas por el calor extremo en las últimas dos décadas, alcanzando el 7,6 ± 0,9% (un error estándar) según las observaciones a nivel nacional y el 8,1 ± 1,1% según el modelo de cultivo que incorpora los mecanismos revelados a partir de experimentos manipulativos. Las precipitaciones extremas reducen el rendimiento del arroz principalmente al limitar la disponibilidad de nitrógeno para el macollaje que reduce las panículas efectivas por área y al ejercer una perturbación física en la polinización que disminuye los granos rellenos por panícula. Teniendo en cuenta estos mecanismos, proyectamos una reducción adicional del rendimiento de ~8% debido a las precipitaciones extremas en climas más cálidos para finales de siglo. Estos hallazgos demuestran que es fundamental tener en cuenta las precipitaciones extremas en las evaluaciones de seguridad alimentaria. Extreme climate events constitute a major risk to global food production. Among these, extreme rainfall is often dismissed from historical analyses and future projections, the impacts and mechanisms of which remain poorly understood. Here we used long-term nationwide observations and multi-level rainfall manipulative experiments to explore the magnitude and mechanisms of extreme rainfall impacts on rice yield in China. We find that rice yield reductions due to extreme rainfall were comparable to those induced by extreme heat over the last two decades, reaching 7.6 ± 0.9% (one standard error) according to nationwide observations and 8.1 ± 1.1% according to the crop model incorporating the mechanisms revealed from manipulative experiments. Extreme rainfall reduces rice yield mainly by limiting nitrogen availability for tillering that lowers per-area effective panicles and by exerting physical disturbance on pollination that declines per-panicle filled grains. Considering these mechanisms, we projected ~8% additional yield reduction due to extreme rainfall under warmer climate by the end of the century. These findings demonstrate that it is critical to account for extreme rainfall in food security assessments. تشكل الظواهر المناخية المتطرفة خطرًا كبيرًا على الإنتاج الغذائي العالمي. من بين هذه العوامل، غالبًا ما يتم استبعاد هطول الأمطار الغزيرة من التحليلات التاريخية والتوقعات المستقبلية، والتي لا تزال آثارها وآلياتها غير مفهومة جيدًا. هنا استخدمنا الملاحظات طويلة الأجل على الصعيد الوطني وتجارب التلاعب بهطول الأمطار متعددة المستويات لاستكشاف حجم وآليات تأثيرات هطول الأمطار الشديدة على محصول الأرز في الصين. نجد أن انخفاضات غلة الأرز بسبب هطول الأمطار الغزيرة كانت مماثلة لتلك الناجمة عن الحرارة الشديدة على مدى العقدين الماضيين، حيث وصلت إلى 7.6 ± 0.9 ٪ (خطأ قياسي واحد) وفقًا للملاحظات على مستوى البلاد و 8.1 ± 1.1 ٪ وفقًا لنموذج المحاصيل الذي يتضمن الآليات التي تم الكشف عنها من التجارب التلاعبية. يقلل هطول الأمطار الغزيرة من غلة الأرز بشكل أساسي عن طريق الحد من توافر النيتروجين للحراثة التي تقلل من السنابل الفعالة لكل منطقة وعن طريق ممارسة الاضطراب الجسدي على التلقيح الذي يقلل من الحبوب المملوءة بالجسيمات. وبالنظر إلى هذه الآليات، توقعنا انخفاضًا إضافيًا في الغلة بنسبة 8 ٪ تقريبًا بسبب هطول الأمطار الغزيرة في ظل مناخ أكثر دفئًا بحلول نهاية القرن. توضح هذه النتائج أنه من الأهمية بمكان مراعاة هطول الأمطار الغزيرة في تقييمات الأمن الغذائي.