• Energy Research
• 2021-2025close
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Cities are progressively heightening their climate aspirations to curtail urban carbon emis- sions and establish a future where economies and communities can flourish within the Earth’s eco- logical limits. Consequently, numerous climate initiatives are being launched to control urban car- bon emissions, targeting various sectors, including transport, residential, agricultural, and energy. However, recent scientific literature underscores the disproportionate distribution of climate poli- cies. While cities in the Global North have witnessed several initiatives to combat climate change, cities in the Global South remain uncovered and highly vulnerable to climate hazards. To address this disparity, we employed the Balanced Iterative Reducing and Clustering using the Hierarchies (BRICH) algorithm to cluster cities from diverse geographical areas that exhibit comparable socio- economic profiles. This clustering strives to foster enhanced cooperation and collaboration among cities globally, with the goal of addressing climate change in a comprehensive manner. In summary, we identified similarities, pa􏰀erns, and clusters among peer cities, enabling mutual and generaliza- ble learning among worldwide peer-cities regarding urban climate policy exchange. This exchange occurs through three approaches: (i) inner-mutual learning, (ii) cross-mutual learning, and (iii) outer-mutual learning. Our findings mark a pivotal stride towards a􏰀aining worldwide climate ob- jectives through a shared responsibility approach. Furthermore, they provide preliminary insights into the implementation of “urban climate policy exchange” among peer cities on a global scale.

Digital Annex for the following thesis: Vila-Viçosa, C. (2023). Natural History, Biogeography and Evolution of the Iberian white oak syngameon (Quercus L. Sect. Quercus). Ph.D. Thesis, Faculdade de Ciências da Universidade do Porto, Portugal Abstract: The genus Quercus L. is one of the most diverse and important group of woody plants, particularly when considering that they are the trees that rule the Northern Hemisphere forests. Oaks have an intricate Biogeography that criss-crosses diverse climatic and edaphic gradients, encompassing a huge ambiguity in terms of species delimitation. Frequently, the taxonomic proposals brought by traditional Linnaean Botany are either insufficient or rather inflate the number of species and nomenclatural assignments, which are further diluted into inconsistent taxonomic ranks, varying from species to subspecies and varieties. The supremacy given to morphological characters that are inherently fragile and plastic, spread across the distribution areas of distinct lineages, may carry ambiguity on the identification and proper species delimitation. From the oaks that are distributed across the Western Palearctic region, the ones that are deciduous or brevi-deciduous present higher levels of ambiguity in terms of species number and their delimitation. This ambiguity is particularly strong in the circummediterranean region and in the transitional areas between the two major biogeographic Regions of the western Palearctic region, the Euro-Siberian and Mediterranean. This degree of uncertainty, which increases towards the Southern European Peninsulas, is amplified by the ease that the different species of oaks tend to hybridize among them. The present work provides a holistic framework that covers multiple areas, from the taxonomic and evolutive study of this genus, to biogeography and molecular characterization. Its major objective was to resolve the species delimitation of the Iberian deciduous and marcescent oaks and putative introgression among them, enhancing the available knowledge about species diversity, which can foster suitable species and forest conservation. A specific objective was to cross-reference the natural history revision and the different taxonomic treatments brought by distinct authors, with personal observations. These data were then incorporated into ecological modelling and molecular characterization, which in the end fed a newly updated taxonomic proposal. In Section A we obtained results from extensive field, herbaria, and literature review, updating the nomenclature of the Portuguese and western Mediterranean oaks. Section B was supported by Section A’s in-depth review and enabled finer species distribution models, nurturing both hindcast (since ca. 20 Kyr) and forecast (2070-2100) exercises of the range dynamics of Mediterranean oaks species. The study of past and future range shifts solved important pending biogeographic questions, especially related to past range-shifts. Such past-range shifts improved our knowledge on species responses to climate dynamics and allowed a better anticipation of future responses of range shifts driven by climate change. Section C encompassed the molecular characterization of Iberian white oak species and their hybrids, whose delimitation is often faltering when one intends to infer about species rank, or hypothesize about the participation of parent taxon in natural hybrid swarms. This work allowed us to solve the phylogenetic backbone of western Palearctic white oaks, suggesting a significant segregation of the Iberian pedunculate oaks and unveiling two subsections inside Section Quercus. These subsections are biogeographically well-segregated and present diverse levels of introgression among species. Results demonstrated the efficiency of RADSeq for rebuilding the reticulate phylogeny of the Eurasian white oaks, showcasing the significance of the Iberian Peninsula as a major hotspot for oak diversity. We implemented a circular approach to these methods, which retro-fed themselves in terms of insight generation, enabling a powerful strategy to solve the evolutionary history of this difficult groups of plants. We estimate that the reticulate historical biogeography of the western Palearctic white oaks deserves further scrutiny by adding vicariant oak populations from northern Africa, the Near East and southern European Peninsulas. Methods should again follow this similar additive and sequential process of adjoining deep Natural History examination, with extensive fieldwork in type populations and genome-wide molecular surveys, in order to solve this group of plants. With the present work, we were able to significantly improve on the depiction of the basic unit of Biodiversity (the Species), in the complex Quercus genus. We provided tools to enable further efforts for the conservation of the Mediterranean oak forests, which overwhelm one of the most important (and one of the most threatened) Biomes for plant conservation at the global scale.

Wide‐bandgap (WBG) perovskite solar cells (PSCs) are acknowledged as promising candidates for tandem solar cells and building photovoltaics. It is well known that cesium‐based all‐inorganic halide WBG perovskites possess the comparable optoelectronic properties as the organic–inorganic counterparts, but exhibit superior thermal stability. Among them, CsPbIBr2 is considered a feasible material for tandem solar cells after balancing the bandgap and stability of the inorganic perovskite. However, CsPbIBr2 PSCs are often subjected to drastic interfacial charge recombination especially in carbon‐based device structure derived from the chemical bonding defects (i.e., uncoordinated Pb2+) naked on CsPbIBr2 soft lattice, which dramatically limits overall efficiency of CsPbIBr2 WBG PSCs. Herein, a trimethyl ammonium salt hexyltrimethylammonium bromide is presented for CsPbIBr2/carbon interfacial modification. Benefiting from the −N+(CH3)3 passivation effect and −C6H13 hydrophobic alkyl chain, the optimal device with highly smooth morphology and sufficient charge extraction exhibits a champion power conversion efficiency of 11.24% and improved long‐term stability with 99.7% and 79.7% efficiency retention under dry air atmosphere and continuous 85 °C thermal stress, indicating the valuable potential application of the lattice solidified CsPbIBr2 WBG PSCs.

Since long ago, pelagic Sargassum mats have been known to be abundant in the Sargasso Sea, where they provide habitat to diverse organisms. However, over the last few years, massive amounts of pelagic Sargassum have reached the coast of several countries in the Caribbean and West Africa, causing economic and environmental problems. Aiming for lessening the impacts of the blooms, governments and private companies remove the seaweeds from the shore, but this process results expensive. The valorization of this abundant biomass can render Sargassum tides into an economic opportunity and concurrently solve their associated environmental problems. Despite the diverse fields where algae have found applications and the relevance of this recurrent situation, Sargassum biomass remains without large scale applications. Therefore, this review aims to present the potential uses of these algae, identifying the limitations that must be assessed to effectively valorize this bioresource. Due to the constraints identified for each of the presented applications, it is concluded that a biorefinery approach should be developed to effectively valorize this abundant biomass. However, there is an urgent need for investigations focusing on holopelagic Sargassum to be able to truly valorize this seaweed.

Plastic film mulching (FM) became a general practice to enhance crop productivity and its net primary production (NPP), but it can increase greenhouse gas (GHG) emissions. The proper addition of organic amendments might effectively decrease the impact of FM on global warming. To evaluate the feasibility of biomass addition on decreasing this negative influence, cover crop biomass as a green manure was incorporated with different recycling levels (0-100% of aboveground biomass) under FM and no-mulching. The net global warming potential (GWP) which integrated with soil C stock change and GHG (N2O and CH4) fluxes with CO2-equivalent was evaluated during maize cultivation. Under the same biomass incorporation, FM significantly enhanced the grain productivity and NPP of maize by 22-61 and 18-58% over no-mulching, respectively. In contrast, FM also highly increased the respired C loss, which was 11-95% higher than NPP increase, over no-mulching. Irrespective with biomass recycling ratio and mulching system, negative NECB which indicates the decrease of soil C stock was observed, mainly due to big harvest removal. FM decreased more soil C stock by 57-158% over no-mulching, but its C stock was clearly increased with increasing biomass addition. FM significantly increased total N2O and CH4 fluxes by 4-61 and 140-600% over no-mulching, respectively. Soil C stock changes mainly decided net GWP scale, but N2O and CH4 fluxes negligibly influenced. As a result, FM highly increased net GWP over no-mulching, while this net GWP was clearly decreased with increasing biomass application. However, cover cropping, and its biomass recycling was not enough to compensate the negative impact of FM on global warming. Therefore, more biomass incorporation might be essential to compensate this negative effect of FM.

Inert gas is often used in the deoxygenation of microbial electrolysis cells (MECs) to maintain growth and viability of anaerobes. However, the effects of the gas atmosphere on hydrogen production and microbial community of MECs are often neglected. Here, the performances and biofilm microbiomes of MECs pre-sparged with different gases were compared. MECs pre-sparged with argon gas (Ar) yielded more hydrogen (3.73 ± 0.13 mol-H2/mol-acetate) and a higher hydrogen production rate (2.99 ± 0.17 L-H2/L-reactor-day) than MECs pre-sparged with N2 (3.41 ± 0.13 mol-H2/mol-acetate and 2.27 ± 0.28 L-H2/L-reactor-day, respectively). Microbiome analysis indicated that the relative abundance of Geobacter increased from 59.25% to 77.79% when the gas atmosphere in MECs shifted from N2 to Ar. Hydrogen production may have been catalyzed by nitrogenase from Geobacter and photosynthetic bacteria in MECs pre-sparged with Ar. These findings suggested that the gas atmosphere substantially influences the microbiome of anode biofilms and Ar sparging is most effective for enhancing hydrogen production in MECs.

Abstract Transportation de-carbonization is a complex problem involving the economy, population, technology and environment. Implementing the pathway simulation based on systematic methods will help to optimize the transportation sustainability plan. This study’s key motivation is that earlier research ignored the relationship between driving factors and the transmission process. To quantitatively identify the path and process of emission reduction, a hybrid system dynamics STIRPAT-SD model is proposed to explore the transportation optimization’s de-carbonization ability. This study fully considers the composition of elements and subsystems based on the STIRPAT theoretical model and visually shows the system’s feedback relationship. Transportation structural and technical optimization scenarios are set to identify the threshold reduction paths. It is found these optimization strategies have significant de-carbonization effects. And transportation structure policy has the highest de-carbonization efficiency, the emission intensity decreased by 9.1% under the TSS2 scenario (Transportation structure scenario). This study proposes a novelty model combining dynamic simulating processes with a significantly theoretical model to improve simulation and factor composition accuracy. And the joint scenario setting identifies the most effective de-carbonization pathway and clarifies the threshold of all possible pathways. Research findings can effectively track, test, predict the achievement of policy goals, and provide policy optimization references for the sustainable development related to the transportation system in practice.

China is the largest fruit producer and consumer market in the world. Understanding the growing conditions responses to climate change is the key to predict future site suitability of main cultivation areas for certain deciduous fruit trees. In this study, we used dynamic and growing degree day models driven by downscaled daily temperatures from 22 global climate models to project the effects of climate change on growing conditions for deciduous fruit trees under two representative concentration pathway (RCP) 4.5 and RCP8.5 scenarios over 2 future time periods (represented by central years 2050s and 2085s) in northern China. The results showed a general increase of available winter chill for all sites under RCP4.5 scenario, and the most dramatic increase in chill accumulation could reach up to 36.8% in northeast regions for RCP8.5. However, the forecasted chill will decrease by 6.4% in southeast stations under RCP8.5 by 2085s. Additionally, the increase rate of growing season heat showed spatially consistency, and the most pronounced increase was found in the RCP8.5 by 2085s. For the southwest station, median heat accumulation increased by 20.8% in the 2050s and 37.1% in the 2085s under RCP8.5. Similar increasing range could be found in the northeast station; the median growing season heat increased by 19.8% and 38.8% in the 2050s and 2085s under RCP8.5, respectively. Moreover, the date of last spring frost was expected to advance and the frequency of frost occurrences was projected to decline in the study area compared to the past. Overall, the present study improves understanding regarding site-specific characteristics of climatic suitability for deciduous fruit tree cultivation in main producing regions of northern China. The results could provide growers and decision-makers with theoretical evidence to take adaptive measure to ensure fruit production in future.

Purpose This study aims to consider environmental sustainability, a global challenge under the preview of sustainable development goals, highlighting the significance of knowledge economy in attaining sustainable aggregate demand behavior globally. For this purpose, 155 countries that have data available from 1995 to 2021 were selected. The purpose of selecting these countries is to test the global responsibility of the knowledge economy to attain environmental sustainability. Design/methodology/approach Results are estimated with the help of panel quantile regression. The empirical existence of aggregate demand-based environmental Kuznets curve (EKC) was tested using non-linear tests. Moreover, principal component analysis has been incorporated to construct the knowledge economy index. Findings U-shaped aggregate demand-based EKC at global level is validated. However, environmental deterioration increases with an additional escalation after US$497.945m in aggregate demand. As a determinant, the knowledge economy is reducing CO2 emissions. The knowledge economy has played a significant role in global responsibility, shifting the EKC downward and extending the CO2 reduction phase for every selected country. Further, urbanization, energy intensity, financial development and trade openness significantly deteriorate the environmental quality. Originality/value This study contains the empirical existence of aggregate demand-based EKC. The role of the knowledge economy is examined through an index which is calculated by using four pillars of the knowledge economy (technology, innovations, education and institutions). This study is based on a combined panel of all the countries for which the data was available.