Wasted Food, Wasted Resources? A Critical Review of Environmental Impact Analysis of Food Loss and Waste Generation and Treatment.

Food loss and waste (FLW) comes with significant environmental impacts and thus prevents a sustainable food system transition. Here we conducted a systematic review of 174 screened studies that assessed the environmental impacts of FLW generation and treatment. We found that the embodied impacts of FLW along the supply chain and impacts from FLW treatment received equal attention, but few studies have included both. The reviewed studies show narrow geographical (mostly conducted in industrialized countries) and food supply chain (mostly focused on the consumption stage) coverage. Life cycle analysis (LCA), material flow analysis (MFA), or their combination are the most commonly used to quantify FLW related environmental impacts. More method standardization, integration, and innovation and better FLW data with regional and stage resolution from a first-hand source are badly needed. Among the various proposed mitigation strategies covering technology, economy, behavior, and policy aspects, process optimization and waste management options are the most discussed. Our review calls for a more holistic environmental impact assessment of FLW generation and treatment and analysis of the trade-offs among different environmental impact categories and between supply chain stages, which would better inform relevant policy on effective environmental impact mitigation strategies toward sustainable food systems.

Carbon Trading in China Reduces the Dependence of Household Waste Electrical and Electronic Equipment Recycling on Government Subsidies.

China's enterprises of waste electrical and electronic equipment (WEEE) recycling suffer from low profitability that is highly dependent on government subsidies. This low economic gain impedes the sustainable growth of China's WEEE-recycling sector and also adds to the government's financial burden. Prior life-cycle studies have approved the carbon reduction potentials or net carbon credit of recycling WEEE. However, policymakers fail to know whether the revenue from selling carbon credits can offset the government's financial subsidy. We performed life-cycle and cost-benefit analyses for a case recycling enterprise that processes six categories of household appliances. The results show that the reduction potentials of greenhouse gases range from 930-3450 kgCO2e by recycling per ton of household appliances and materials substitution. The recycling enterprise would gain extra revenue ranging from 32 to 160 RMB per ton of appliance if the carbon credits were sold at China's current carbon price, i.e., 45-60 RMB tCO2e-1. Recycling waste refrigerators exhibits the highest carbon revenue, offsetting 6-17% of the government's financial subsidy. Microcomputers, by contrast, indicate the lowest carbon revenue, equivalent to 1-3% of its highest government subsidy. For each household appliance category, when the carbon price reaches 270-600 RMB tCO2e-1, selling carbon credits can fully offset the government's financial subsidy. Constrained by the processing capacity of the case enterprise, optimizations for appliance-recycling composition contribute a 15-25% profit growth to the current economic gains. Interpreting the specific profit depends on the predefined scenarios of carbon price and the substitution rate of the regenerated materials for the virginal ones. Our findings show that raising the profitability of WEEE recycling enterprises through the carbon trading policy contributes to the sustainable growth of China's WEEE-recycling sector while alleviating the government's financial burden.

Scenario analysis on optimal farmed-fish-species composition in China: A theoretical methodology to benefit wild-fishery stock, water conservation, economic and protein outputs under the context of climate change.

Fish production from aquaculture and wild captures suffers from the rising risk of climate change. This impacts the livelihoods of fishers and fish farmers by shrinking wild fishery stocks, inland water scarcity, and consequent declines in economic and protein productions. China, feeding the most fish of the world with water-intensive crops, faces challenges of water scarcity but still be premature in developing strategies to adapt to climate change. Here, focusing on methodology development, we quantified the water footprint of fish-farming and economic and protein productions in the baseline year 2014. Then, 29 scenarios of farmed-fish-species composition (FFSC, i.e., tons of each farmed fish species) were developed for the target year 2020. The baseline 2014 shows that fish farming generates an average of 150 billion m3 of water footprint, 4.70 million tons of protein, and 263 billion RMB of economic output (~39 billion USD). Uncertainty optimizations were conducted to generate the optimal FFSC solutions that show a potential to increase fish production by 22%, economic and protein output by 18% and 29%, respectively and simultaneously lower water footprint by 22% to the maximum extent. Nine scenarios that lower wild fishery captures were further examined, with optimal FFSC solution that encourages aquaculture of Grass carp, Bighead Carp, and Silver Carp, and discourages Black carp, Tilapia, Crucian carp, Sea bass, and Wuchang bream. From a methodology aspect, this study pulls back policymakers from only focusing on the short-term economic interest of fish-farming and persuades them to rethink long-term adaptive strategies to climate change from multiple sustainable dimensions.

Environmental Burdens of China's Propylene manufacturing: Comparative life-cycle assessment and scenario analysis.

China's propylene feedstock shifts from oil to imported cheap propane and local coal. However, the associated environmental loads of this feedstock change have seldom been investigated for China's propylene industry. Herein, environmental impacts of the four typical propylene production routes, coal to olefin (CTO), propane dehydrogenation (PDH), steam cracking (SC), and catalytic cracking (CC) process, were compared by life-cycle-assessment (LCA) methodology. Two metrics, midpoint environmental impacts (including nine indicators) and the comprehensive index of energy conservation and emission reduction (ECER), were adopted for this evaluation. The midpoint-impact indices show the trade-offs across the nine environmental dimensions. Thus, it is not easy to rank the environmental advantage of the four production routes. The ECER indices indicate the highest environmental loads in the CTO process, followed by PDH and the comparable SC and CC routes. Raw materials consumption dominates the environmental burden generations of the PDH, SC, and CC routes. Scenario analysis shows that feedstock shift and capacity growth jointly increase the environmental burdens of China's propylene industry by 27-66% in 2025 and 60-111% in 2030, relative to the 2018 baseline. Notably, global-warming potential inevitably increases due to replacing the conventional oil-fed SC/CC capacity either by coal-fed CTO or by propane-fed PDH route. The findings suggest that the feedstock shift of the propylene industry deserves close attention to promote the environmental sustainability of the Chinese chemical manufacturing industry.

Climatic burden of eating at home against away-from-home: A novel Bayesian Belief Network model for the mechanism of eating-out in urban China.

Dietary patterns of eating away-from-home (AFH) considerably differ from those of eating at home in urban China, thus generating varied carbon footprints. However, few studies have investigated the effect of eating places on diet-related climatic burden, and few have modelled the mechanism under the condition of eating-out because the decision of consumers on whether to eat AFH or at home is determined by multiple non-linear socioeconomic factors. Here, we compared the carbon footprints of eating at home and AFH using household survey data from 12 Chinese provinces, and developed a Bayesian Belief Network (BBN) model to identify key factors of eating AFH. Our findings show that eating AFH leads to higher climatic burdens though respondents consume less food on average than when eating at home. However, in urban areas, the carbon footprint generated increases more rapidly from eating at-home than when eating AFH. The BBN model was found to have strong capability to predict the possibility of eating out with an accuracy of 89%. Although diet patterns and embedded carbon footprint vary considerably across provinces from northeastern to southwestern China, sufficient evidence could not be found to support the influence of geographic factors on the decision of respondents to eat AFH at large scale. Instead, individual occupation and income were found to be the two key contributors. Thus, merely estimating the carbon footprint of food consumption is currently not sufficient, but social and economic elements need to be quantitatively considered to differentiate the eating-place effect on diet-related climatic burden.

Risk assessment and hierarchical risk management of enterprises in chemical industrial parks based on catastrophe theory.

According to risk systems theory and the characteristics of the chemical industry, an index system was established for risk assessment of enterprises in chemical industrial parks (CIPs) based on the inherent risk of the source, effectiveness of the prevention and control mechanism, and vulnerability of the receptor. A comprehensive risk assessment method based on catastrophe theory was then proposed and used to analyze the risk levels of ten major chemical enterprises in the Songmu Island CIP, China. According to the principle of equal distribution function, the chemical enterprise risk level was divided into the following five levels: 1.0 (very safe), 0.8 (safe), 0.6 (generally recognized as safe, GRAS), 0.4 (unsafe), 0.2 (very unsafe). The results revealed five enterprises (50%) with an unsafe risk level, and another five enterprises (50%) at the generally recognized as safe risk level. This method solves the multi-objective evaluation and decision-making problem. Additionally, this method involves simple calculations and provides an effective technique for risk assessment and hierarchical risk management of enterprises in CIPs.