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AbstractChina is under pressure to improve its agricultural productivity to keep up with the demands of a growing population with increasingly resource‐intensive diets. This productivity improvement must occur against a backdrop of carbon intensity reduction targets, and a highly fragmented, nutrient‐inefficient farming system. Moreover, the Chinese government increasingly recognizes the need to rationalize the management of the 800 million tonnes of agricultural crop straw that China produces each year, up to 40% of which is burned in‐field as a waste. Biochar produced from these residues and applied to land could contribute to China's agricultural productivity, resource use efficiency and carbon reduction goals. However competing uses for China's straw residues are rapidly emerging, particularly from bioenergy generation. Therefore it is important to understand the relative economic viability and carbon abatement potential of directing agricultural residues to biochar rather than bioenergy. Using cost‐benefit analysis (CBA) and life‐cycle analysis (LCA), this paper therefore compares the economic viability and carbon abatement potential of biochar production via pyrolysis, with that of bioenergy production via briquetting and gasification. Straw reincorporation and in‐field straw burning are used as baseline scenarios. We find that briquetting straw for heat energy is the most cost‐effective carbon abatement technology, requiring a subsidy of $7 MgCO2e−1 abated. However China's current bioelectricity subsidy scheme makes gasification (NPV $12.6 million) more financially attractive for investors than both briquetting (NPV $7.34 million), and pyrolysis ($−1.84 million). The direct carbon abatement potential of pyrolysis (1.06 MgCO2e per odt straw) is also lower than that of briquetting (1.35 MgCO2e per odt straw) and gasification (1.16 MgCO2e per odt straw). However indirect carbon abatement processes arising from biochar application could significantly improve the carbon abatement potential of the pyrolysis scenario. Likewise, increasing the agronomic value of biochar is essential for the pyrolysis scenario to compete as an economically viable, cost‐effective mitigation technology.

This paper presents a literature review on urban design indicators addressing the impact of urban geometry and vegetation on the outdoor thermal environment at the pedestrian level, as urban geometry and vegetation have been regarded as the most influential urban design factors that affect outdoor microclimate. The thermal balance concept is first introduced to elaborate how each component of energy fluxes is affected by the urban built environment, which helps to explore the underlying thermophysical mechanisms of how urban design modifies the outdoor thermal environment. The literature on numerous urban design descriptors addressing urban geometric characteristics is categorized into five groups in this paper according to the design features that the parameters entail, including land use intensity, building form, canyon geometry, space enclosure and descriptive characteristics. The literature on urban vegetation descriptors is reviewed together, followed by the combined effect of urban geometry and vegetation. This paper identifies a series of important urban design parameters and shows that the impact of design parameters on thermal environment varies with time, season, local climate and urban contexts. Contradictory impacts often occur between daytime and nighttime, or different seasons, which requests trade-offs to be achieved when proposing design strategies.

Valorisation of food waste offers an economical and environmental opportunity, which can reduce the problems of its conventional disposal. Food waste is commonly disposed of in landfills or incinerated, causing many environmental, social, and economic issues. Large amounts of food waste are produced in the food supply chain of agriculture: production, post-harvest, distribution (transport), processing, and consumption. Food waste can be valorised into a range of products, including biofertilisers, bioplastics, biofuels, chemicals, and nutraceuticals. Conversion of food waste into these products can reduce the demand of fossil-derived products, which have historically contributed to large amounts of pollution. The variety of food chain suppliers offers a wide range of feedstocks that can be physically, chemically, or biologically altered to form an array of biofertilisers and soil amendments. Composting and anaerobic digestion are the main large-scale conversion methods used today to valorise food waste products to biofertilisers and soil amendments. However, emerging conversion methods such as dehydration, biochar production, and chemical hydrolysis have promising characteristics, which can be utilised in agriculture as well as for soil remediation. Valorising food waste into biofertilisers and soil amendments has great potential to combat land degradation in agricultural areas. Biofertilisers are rich in nutrients that can reduce the dependability of using conventional mineral fertilisers. Food waste products, unlike mineral fertilisers, can also be used as soil amendments to improve productivity. These characteristics of food wastes assist in the remediation of contaminated soils. This paper reviews the volume of food waste within the food chain and types of food waste feedstocks that can be valorised into various products, including the conversion methods. Unintended consequences of the utilisation of food waste as biofertilisers and soil-amendment products resulting from their relatively low concentrations of trace element nutrients and presence of potentially toxic elements are also evaluated.

Societal relations in rural areas have entered into a new stage of adjustment over the past decade. However, the adjustment, which might bring about profound societal changes in countryside as well as in China as a whole, have not been paid much attention and very few studies have been conducted from the perspective of ecological resource crises. We use the case of a village as an example to show how water pollution, as one of the contributory factors, possibly affect the transition of clans and societal changes in Chinese villages. Through observation and interviews, we find that there is an apparent rise of “New Clanism” within clans, which gradually abandons the tradition of supremacy of clan interests and places family or individual interests at top priority. We also find that clan boundaries get increasingly obscure since the integrity of clans is undermined by the rise of new interest groups across clans, but the boundaries remain relatively clear due to the consistency (albeit incomplete) of clan interests. Some new clan élites and representatives of new interest groups get involved in village governance, which indicates that their goals have shifted from natural resources to social or political capital. The significance of our findings is that they provide not only a unique perspective for the interaction between society and resources, but also some new ideas for the future study of rural China at the environment-social interface.

Abstract The study quantifies the benefits of expanding electric cooking in the residential sector in terms of kerosene and fuel wood saved from the perspective of long term optimal energy system development of Bhutan. It also investigates the reductions in the emissions of CO2 and the indoor pollutants, SO2 and NOx due to fuel switching in the cooking enduse. This study method is based on the first ever integrated long-term energy system modeling in Bhutan, which was undertaken previously by the lead author as a master thesis work but not published. The energy system model for Bhutan was developed under the MARKAL model framework. In Bhutan electricity generation is pre-dominantly hydropower based on run-of-the-river schemes. The model results indicate that a sectoral level policy to promote electric cooking reduces the use of kerosene by 1832 kiloliters and fuelwood by 55 kilotonnes per annum which consequently leads to reductions in the emissions of CO2, SO2 and NOx by 17%, 12% and 8% respectively. The electric cooking scenario also complements the vision of Bhutan to reduce deforestation and to remain carbon neutral for all times to come.

Many scientists have expressed concern that declining agricultural diversity threatens agricultural sustainability. We draw on the available literature to outline and examine mechanisms that reduce agricultural diversity and identify the at-risk attributes of agricultural sustainability. Using a three-pillar concept embodying ecological, social and economic dimensions, this article provides a comprehensive general assessment of the sustainability of agricultural systems. It pays particular attention to consequences for agricultural diversity and sustainability of the increasing dependence of agriculture on the market system and new agricultural technologies. As an illustrative example, it examines changes in the diversity and sustainability of Bangladeshi agriculture by applying a novel index of the diversity of cropping land use, an output decomposition method, and statistical techniques. Crop diversity in Bangladesh is very low and dominated by the cultivation of rice, which now depends very heavily on a limited number of high yielding varieties (HYVs). Higher rice yields in Bangladesh and seasonal changes in rice cultivation have resulted in land sparing, which make room for greater crop diversity. Nevertheless, Bangladesh’s food dependence on its rice output is very high and is critically dependent on groundwater irrigation. We recommend that Bangladesh consider increasing the diversity of its crops as a food security measure and as a hedge against a decline in its agricultural sustainability.

AbstractIdentifying the location and amount of grain crop residues (stubble) in Australia is necessary for determining the viability of potential biofuel plant locations. We combined 22 years of crop statistics with harvest indices and land use to arrive at spatially explicit stubble productivity figures. Stubble quantities using different focal radii and from different seasons provide an insight into the feasibility of its use for bioenergy. We focus on areas where the stubble concentrations within a 50 km radius were at least 500 kt per year; the amount suggested for a viable lignocellolosic bioethanol facility. The outcome of this study has been to show, for the first time, where there are large amounts of stubble in Australia. Whether the supply of stubble is sufficiently constant over time and indeed available at a price that is economic for a biofuel plant must be subject to future work.