Know your carbon footprint from your environmental impact


Carbon footprint, environmental impact, greenhouse gas emissions, we hear the terms all the time, but what do any of them actually mean? Let’s demystify the jargon.

Carbon footprint refers to the quantity of greenhouse gas emissions associated with a person, activity, or thing. There are other gases that have a warming effect too, like methane and nitrous oxide. When the term carbon footprint is used, the warming effect of all the greenhouse gas emissions from the activity are already included in the figure. The method used to include them is called Carbon Dioxide Equivalent (CO2e). It's simply looking at the warming effect of a gas and writing how much CO2 would be needed to have the same warming effect. It's not a perfect system, as some gases live longer in the atmosphere than others, but it's the international standard. Carbon footprint is often interchanged with the term climate impact and they both have the same meaning. The lower the carbon footprint, the lower the climate impact. To bring the impact of your food purchases in line with the Paris Climate Accord goal of limiting global temperature rise to 1.5 degrees, your food needs to have an impact of 65kg of CO2e each month or less by 2030.

The greenhouse effect is the name given to how certain gases trap extra heat in the atmosphere and causes the planet to warm. Greenhouse gases are the gases that are known to cause the greenhouse effect, and the principal offenders are CO2, Methane, Nitrous and Sulfur Oxides. Each gas causes a different amount of warming, or has a different global warming potential. To make things simpler, all are normalised to what the equivalent amount in CO2 is, this is written as CO2e. Greenhouse gas emissions are measured in mass (grams, kilograms, tonnes, megatonnes, gigatonnes).

Environmental impact is a broad term used to describe anything that has a negative impact on the environment. This can be anything from water pollution to CO2 emissions to microplastics. Climate impact is just one small subset of the many environmental impacts that result from human activity. The catch here is that somethings can have both a very high environmental impact and a moderate climate impact at the same time. Single use plastic is a good example. It has low recycling rates and is a common cause of litter, polluting every corner of the planet, even the Mariana Trench. It has a terrible environmental impact. However, this kind of plastic causes less greenhouse gas emissions than almost any alternative, including paper bags and cotton totes, giving it a favourable climate impact. Knowing the difference in the terminology can help you make the most holistically sustainable decision. For scoring food products, Evocco just focuses on greenhouse gas emissions for now.

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