4． 碳足迹，即carbon footprint。简单地说，碳足迹是用来衡量我们在日常生活中消耗的二氧化碳的一种方式。无论是开车上班、乘飞机旅行，还是使用电灯、电脑，我们都消耗石油、煤和天然气等化石燃料。这些化石燃料在燃烧时，会排放出诸如二氧化碳之类导致地球变暖的温室气体。对于carbon footprint，维基百科有如下定义：A carbon footprint is "the total set of greenhouse gas (GHG) emissions caused by an organization, event or product". For simplicity of reporting, it is often expressed in terms of the amount of carbon dioxide, or its equivalent of other GHGs, emitted. 相关表达见如下例句：A new purpose-built office complex that will offer eco-friendly accommodation across 66,250 square feet is under construction in Wales. It is reported that the Cardiff Waterside project, entitled 3 Assembly Square, forms part of a £140 million construction project and will aim to offer business in the area an environment that has a lower carbon footprint than traditional office space. 上述句子的背景是，英国政府成立了一个The Low Carbon Building Programme (LCBP)，即低碳建筑计划，维基百科解释说，

LCBP is a Government programme in the United Kingdom administered by BERR (formerly the DTI). It offers grants towards the cost of installing domestic microgeneration technologies and larger scale distributed generation installations for public buildings and businesses, provided energy conservation standards are also met.