emission – n. the act of sending gas, heat or light out into the air

equivalent – adj. having the same amount, value, quality etc.

per – prep. used when expressing rates, prices or measurements

calibrate – v. to mark units of measurement on an instrument so that it can measure accurately

refine – v. make a substance pure by removing unwanted material

global warming – n. a gradual increase in world temperatures caused by gases such as carbon dioxide

align – v. support a particular group or cause

fossil fuel – n. a fuel, such as coal, oil, or natural gas, that is formed in the earth from dead plants or animals

practical – adj. relating to experience or real situations rather than ideas or imagination

data – n. information, especially facts or numbers, collected to be examined and considered in a decision-making process