Evaluating the carbon footprint of a Spanish city through environmentally extended input output analysis and comparison with life cycle assessment

The temporal variation of CH4 emissions embodied in Chinese supply chains, 2000-2020

Although the issue of embodied pollutants in China's supply chains has garnered increasing attention, the dynamic changes occurring within them are unclear. Several existing studies analyze one-year or short-term data in supply chain. China's overall CH4 emissions have risen from 41.1 Tg in 2000 to 60 Tg in 2020, so conducting long-term analyses can yield a deeper understanding of the dynamic changes across the entire supply chain from production to consumption. This study uses the environmentally extended input-output analysis (EEIOA) and structural path analysis (SPA) methods to investigate the dynamic variation of China's embodied CH4 emissions in 20 industry sectors from 2000 to 2020, aiming to determine the key supply chain and key sectors. The results reveal that from the final demand perspective, consumption, investment and export drove 52.1%, 32%, and 15.9% of embodied CH4 emissions in 2020. The sector with the highest embodied CH4 emissions has changed from "Agriculture" in 2000 to "Construction" in 2010 to "Other service and activities" in 2020. The top listed supply chain path of embodied CH4 emissions has also evolved (starting from production to consumption) from "Agriculture → Rural consumption" in 2000 to "Agriculture → Food and tobacco → Urban consumption" in 2010 to "Agriculture → Urban consumption" in 2020. Notably, the high-ranked path, "Agriculture → Food and tobacco → Rural consumption", shows that the embodied CH4 emission flowing between agriculture and the food industry cannot be ignored. The supply chain path "Coal Mining → Nonmetal Mineral Products → Construction → Capital Formation" has risen from 17th in 2000 to 3rd in 2020. Thus, it is necessary to control CH4 emissions from sectors upstream, which are predominantly influenced by the construction industry, and a coordinated effort between sectors is also required to effectively reduce emissions. By 2020, the CH4 emissions driven by urban consumption were 3.1 times that of rural consumption. This study provides a comprehensive analysis of China's supply chain over the past two decades. In particular, it suggests policy interventions by controlling critical supply chain paths and key sectors associated with embodied CH4 emission, thereby facilitating the coordinated reduction of anthropogenic CH4 emissions.

Spatiotemporal evolution and influence mechanism of the carbon footprint of energy consumption at county level in the Yellow River Basin

Implementing emission reduction policies at county level is important to realize high-quality development in the Yellow River Basin and achieve national "carbon peaking" and "carbon neutrality" goals. Based on remote-sensing data of night light, net primary productivity, and land use, the present study utilized the light‑carbon conversion and carbon footprint measurement models to quantify the carbon footprint of energy consumption. An exploratory spatiotemporal data analysis method was implemented to analyze the spatiotemporal evolution path. Panel quantile regression and spatiotemporal transition-nested models were used to reveal the influence mechanism of the spatiotemporal evolution of the carbon footprint. The following results were obtained. (1) The carbon footprint of counties increased from 2001 to 2020. Counties with high‑carbon footprint diffused around the "one center and two axes". Carbon-deficit counties exhibited a diffused trend towards the west. In 2020, 506 counties exhibited carbon deficits, and the carbon balance of the ecosystem was severely unbalanced. (2) The carbon footprint showed evident path dependence and Matthew effect. The high‑carbon footprint lock-in area comprising 177 counties is a challenging zone for governance. The 86 counties that exhibit carbon footprint changes are the key zones to drive the carbon footprint changes in the Basin. The change direction of the county's carbon footprint type, with evident spatial correlation characteristics, is in accordance with adjacent counties. (3) The carbon footprint spatiotemporal transition types and influence mechanisms in counties exhibited significant differences, with the coexistence of low-carbon footprint driving, low-carbon footprint restriction, high-carbon footprint driving and high-carbon footprint restriction modes. As the influence mechanisms of different modes and the paths to achieve "dual carbon" goals are different, the governance of different modes should focus on optimizing and strengthening restriction factors or controlling and improving of driving factors.

Methodological guidelines for the calculation of a Water-Energy-Food nexus index for seafood products

Indicators from life cycle assessment methodologies (i.e., footprints) have emerged as useful tools for identifying and communicating the environmental impacts of a system thanks to they are accessible and intuitive and easy to understand to non-expert public. However, the focus on a single environmental problem is one of their main drawbacks. From this idea arises the concept of Water-Energy-Food (WEF) nexus, with the aim of raising awareness of the connections between the universal rights to water supply, energy security and food provision. Regarding the latter, the fisheries sector stands out as a fundamental pillar in the fight against malnutrition. In this sense, the European project "blue growth" aims to ensure that the development of the marine sector is not linked to the degradation of its ecosystems. However, although producers and authorities are willing to communicate the sustainability of products, there is still no standard methodology for reporting it. With the purpose of remedying this current situation, this paper aims to provide technical guidance to calculate a single WEF nexus index for ecolabelling seafood products in the European framework (Atlantic area). Therefore, through this, it is expected to create a useful communication channel between producers and consumers through an easy-to-read ecolabel. Nonetheless, certain aspects, such as the footprints selected or the calculation procedures selected have to be reconsidered to refine the methodology proposed, apart from broadening the approach to other food sectors with the aim that the proposed eco-certification can be present in major supply and retail chains.

Contribution of anthropogenic pollutant sources to greenhouse gas emissions: a case study from a developing country

Anthropogenic greenhouse gas (GHG) emissions are the primary cause of climate change, one of the biggest challenges for humankind. To tackle this problem, the international community is looking for ways to reduce GHG emissions. To create reduction strategies in a city/province/country, there is a need for an inventory that provides emission amounts from different sectors. This study aimed to develop a GHG emission inventory for Karaj, a megacity in Iran, using international guidelines such as AP-42 and ICAO, and IVE software. The emissions of mobile sources were accurately calculated by a bottom-up method. The results showed that power plant with 47% of the total emissions is the primary GHG contributor in Karaj. Residential and commercial units with 27% and mobile sources with 24% of the total emissions play a critical role in emitting GHGs in Karaj. On the other hand, the industrial units and the airport have negligible (2%) contribution to the total emissions. Subsequent estimates showed that GHG emissions per capita and per GDP of Karaj were 6.03 t per person and 0.47 t per thousand US dollars, respectively. These amounts are higher than the global averages (4.97 t per person and 0.3 t per thousand US dollars). The relatively high GHG emissions in Karaj are due to the sole reliance on the consumption of fossil fuels. To reduce emissions, mitigation strategies such as developing renewable energy sources, switching to low-emission transportation, and raising public awareness should be implemented.

Pre-construction quantification of embodied environmental impacts to promote sustainable construction projects: The case study of a diversion dam

A quantitative assessment of the embodied environmental impacts of infrastructures can provide initial guidance to industry practitioners and engineers at the outset of the construction projects. This study presents the applicability of the Environmentally Extended Input-Output Analysis as a pre-construction evaluation tool for quantifying the embodied environmental impacts of a small diversion dam in Spain. Seven impact categories are assessed from a production-based and consumption-based perspective identifying the main sectors and regions contributing to the environmental impacts. From the consumption-based perspective, Spain is the only contributor to the environmental impacts, and from the production-based perspective, Spain is the main polluting country in all the impact categories contributing on average 68.9%. The use of high quantities of construction material leads to the sectors of steel and cement to significantly increase the environmental impacts. From the production-based perspective, steel and cement contribute on average 29.5% and 17.2%, respectively. From the consumption-based perspective, both sectors account for 74% of the overall environmental impacts. As observed in this case study, the application of the EEIOA model enables engineers and designers to focus during the early design stages on decisions that achieve high embodied impact reductions, such as prioritizing recycled materials for the construction of this infrastructure and, when possible, use materials from a less polluting origin.

Number of meal components, nutritional guidelines, vegetarian meals, avoiding ruminant meat: what is the best trade-off for improving school meal sustainability?

PURPOSE

School meals have the potential to promote more sustainable diets. Our aim was to identify the best trade-off between nutrition and the environment by applying four levers to school meals: (i) reducing the number of meal components, (ii) complying with the French school nutritional guidelines, (iii) increasing the number of vegetarian meals, and/or (iv) avoiding ruminant meat.

METHODS

Levers were analyzed alone or in combination in 17 scenarios. For each scenario, 100 series of 20 meals were generated from a database of 2316 school dishes using mathematical optimization. The nutritional quality of the series was assessed through the mean adequacy ratio (MAR/2000 kcal). Seven environmental impacts were considered such as greenhouse gas emissions (GHGE). One scenario, close to series usually served in French schools (containing four vegetarian meals, at least four ruminant meat-based meals, and at least four fish-based meals) was considered as the reference scenario.

RESULTS

Reducing the number of meal components induced an important decrease of the energy content but the environmental impact was little altered. Complying with school-specific nutritional guidelines ensured nutritional quality but slightly increased GHGE. Increasing the number of vegetarian meals decreased GHGE (from 11.7 to 61.2%) but decreased nutritional quality, especially when all meals were vegetarian (MAR = 88.1% against 95.3% in the reference scenario). Compared to the reference scenario, series with 12 vegetarian meals, 4 meals containing fish and 4 meals containing pork or poultry reduced GHGE by 50% while maintaining good nutritional quality (MAR = 94.0%).

CONCLUSION

Updating French school nutritional guidelines by increasing the number of vegetarian meals up to 12 over 20 and serving non-ruminant meats and fish with the other meals would be the best trade-off for decreasing the environmental impacts of meals without altering their nutritional quality.

Sustainable Risk Assessment of Resource Industry at Provincial Level in China

The development of China’s resource industry is facing great pressures from industrial structure adjustment and environmental restraints, and the sustainable risk of the provincial resource industry is different. Considering the development of the resource industry and environmental pressure, this article selects the panel data of 31 provinces from 2015 to 2019 to construct an index evaluation system with six dimensions: influence, induction, supply and demand safety, regional pollution emission, environment quality, and pollution control. The results showed that Shanxi, Anhui, Jiangsu, and Shanghai had the highest sustainable risk in the resource industry, while Heilongjiang, Jilin, Tianjin, Fujian, Jiangxi, Hunan, Guizhou, Sichuan, and Qinghai had the lowest sustainable risk. The resource industry model of all the provinces is divided into sustainable, industrial, ecological, and unsustainable. Finally, this article puts forward reasonable suggestions for the four scenarios and argues that the balanced development of the resource industry sector and environmental protection is conducive to reducing the sustainable risks of the resource industry.