Environmental or ‘ecological’ footprints have been widely used in recent years as indicators of resource consumption and waste absorption presented in terms of biologically productive land area [in global hectares (gha)] required per capita with prevailing technology. In contrast, ‘carbon footprints’ are the amount of carbon (or carbon dioxide equivalent) emissions for such activities in units of mass or weight (like kilograms per functional unit), but can be translated into a component of the environmental footprint (on a gha basis). The carbon and environmental footprints associated with the world production of liquid biofuels have been computed for the period 2010–2050. Estimates of future global biofuel production were adopted from the 2011 International Energy Agency (IEA) ‘technology roadmap’ for transport biofuels. This suggests that, although first generation biofuels will dominate the market up to 2020, advanced or second generation biofuels might constitute some 75% of biofuel production by 2050. The overall environmental footprint was estimated to be 0.29 billion (bn) gha in 2010 and is likely to grow to around 2.57 bn gha by 2050. It was then disaggregated into various components: bioproductive land, built land, carbon emissions, embodied energy, materials and waste, transport, and water consumption. This component‐based approach has enabled the examination of the Manufactured and Natural Capital elements of the ‘four capitals’ model of sustainability quite broadly, along with specific issues (such as the linkages associated with the so‐called energy–land–water nexus). Bioproductive land use was found to exhibit the largest footprint component (a 48% share in 2050), followed by the carbon footprint (23%), embodied energy (16%), and then the water footprint (9%). Footprint components related to built land, transport and waste arisings were all found to account for an insignificant proportion to the overall environmental footprint, together amounting to only about 2%

中文翻译：

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到 2050 年与世界生物燃料生产相关的环境和资源负担：从碳排放和土地使用到废物产生和水消耗的足迹组成部分。

近年来，环境或“生态”足迹已被广泛用作资源消耗和废物吸收的指标，以采用流行技术的人均生物生产力土地面积 [以全球公顷 (gha) 表示] 。相比之下，“碳足迹”是以质量或重量为单位（如每功能单位公斤）的此类活动的碳（或二氧化碳当量）排放量，但可以转化为环境足迹的一个组成部分（在gha 基础）。已经计算了 2010-2050 年期间与世界液体生物燃料生产相关的碳足迹和环境足迹。2011 年国际能源署采用了对未来全球生物燃料生产的估计(IEA) 运输生物燃料的“技术路线图”。这表明，尽管到 2020 年第一代生物燃料将主导市场，但到2050年，先进或第二代生物燃料可能占生物燃料产量的 75%。2010 年总体环境足迹估计为 2.9 亿 (十亿) 全球公顷，并且到 2050 年可能会增长到约 25.7 亿全球公顷。然后将其分解为各种组成部分：生物生产用地、建筑用地、碳排放、隐含能源、材料和废物、运输和水消耗。这种基于组件的方法能够检查制造资本和自然资本“四个首都”可持续性模型的要素非常广泛，以及具体问题（例如与所谓的能源-土地-水关系相关的联系）。发现生物生产性土地利用的足迹成分最大（2050 年占 48%），其次是碳足迹（23%）、隐含能源（16%），然后是水足迹（9%）。发现与建筑土地、交通和废物产生相关的足迹成分在整体环境足迹中所占的比例微不足道，合计仅为约 2%