A carbon footprint is the total amount of greenhouse gases produced to directly and indirectly¹ support human activities, usually expressed in equivalent tons of carbon dioxide (CO2). In other words: When you drive a car, the engine burns fuel which creates a certain amount of CO2, depending on its fuel consumption and the driving distance. When you buy food and goods, the production of the food and goods also emitted some quantities of CO2. Even if you heat your house with electricity, the generation of the electrical power may also have emitted a certain amount of CO2.

碳足迹指直接或间接支持人类活动所产生的温室气体总量，通常用产生的二氧化碳吨数来表示。换句话说，你开车的时候，发动机在燃烧汽油的同时会释放出一定量的二氧化碳，这个量由耗油量和行驶里程决定。你购买食物和商品的时候，生产食物和商品的过程也会释放出一定量的二氧化碳。就算你家的房子是用电采暖，电能产生的过程也是释放二氧化碳的。

Your carbon footprint is the sum of all emissions² of CO2, which were induced by your activities in a given time frame. Usually a carbon footprint is calculated for the time period of a year.

你的碳足迹就是在一定时间段内你的所有活动引起的二氧化碳排放总量。通常情况下，碳足迹是以一年为一个时间段进行计算的。