Primary and secondary footprint

Human activity impacts the envirorunent in two ways - directly through processes that bum fossil fuels and indirectly through the products that we use. The carbon footprint is therefore made up of the sum of two parts the primary footprint and the secondary footprint. 

The primary footprint is a measure of the direct emissions of carbon dioxide from fossil fuels we bum including domestic energy consumption and transportation (e.g. car and plane). We have direct control over these emissions. 

The secondary footprint is a measure of the indirect carbon dioxide emissions over the entire lifecycle of the products we use - emissions associated with their manufacture and eventual breakdown. Simply put - the more we buy the more emissions will be caused on our behalf. 

The primary footprint of your commute to the office and back is pretty straightforward to calculate or estimate, but the secondary footprint concept is a little more involved and tricky. To understand the concept, you need to 

If that is not complicated enough, there is no universally accepted way to measure the carbon footprint. For example retailers in the United Kingdom might only consider the emissions in the UK distribution of the T-shirt, accoimting for only part of the supply chain. 

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