Carbon accounting: CO2-equivalents are the new CO2 footprint

A carbon footprint is the amount of carbon dioxide (CO2) and greenhouse gas (GHG) emissions that can be attributed to an entity, whether that be an individual, an item, an activity, a building, a corporation, or a country. This allows us to understand the full climate impact the entity has, and develop ways to lessen it. But how are carbon footprints measured? Read on to find out. 

What is a carbon dioxide equivalent (CO2-e)?

A carbon dioxide equivalent (CO2-e) is the standard unit of measurement for carbon footprints. It includes the direct and indirect emissions from manufacturing, heating, electricity, and transportation that are associated with the entity being evaluated as well as the emissions of related greenhouse gases (GHGs). These include methane (CH4), ozone (O3), nitrous oxide (N2O), and fluorinated gases. The greenhouse gases are expressed as the same amount of CO2 with the equivalent climate warming impact. This results in a single number for a CO2-e, which allows for easy comparisons between different carbon footprints consisting of various amounts of greenhouse gases. 

Greenhouse Gas Global Warming Potential Over 100 Years
Carbon dioxide 1
Methane 28-36
Ozone 2000
Nitrous oxide 265-298
Fluorinated gases up to 22,900

The global warming potential (GWP) of each greenhouse gas is used to convert them into equivalent CO2 amounts. This is essentially the total warming impact of said GHG relative to CO2 over a typical period of a hundred years. GWPs vary across different time periods, however, as certain gases remain longer in the atmosphere than others. Hence, it is impossible for a carbon footprint to be entirely accurate. 

In particular, a lot of uncertainty still remains regarding the GWP for ozone (O3) because its climate impact is subject to complex interactions. O3  is a “secondary pollutant” because it is not emitted directly; rather, it is formed by the reaction of air pollutants such as carbon monoxide (CO), methane (CH4), nitrogen oxides (NOx), and volatile organic compounds (VOCs) in the presence of heat and sunlight. These reactions, along with O3’s interaction with UV radiation and its low atmospheric lifetime, make it difficult to determine an accurate GWP. What is for certain, however, is the impact air pollution has on the climate.

Why is carbon accounting important?

Despite the fact that emission impacts cannot be identified with pin-point accuracy, carbon accounting is essential when it comes to combating climate change. This information assigns responsibility to individuals, companies, and countries, which in turn allows them to set reduction targets to combat climate change.

Breeze Technologies can help. There is an undeniable link between climate change and air pollution, and as such, hyperlocal air quality and climate data is essential for identifying pollution hotspots so that targeted actions can be implemented, monitored, and optimized. Our AI-powered air quality sensors do just that. Their small, compact form factors allow for easy deployment and measure for the most important air quality parameters to provide an accurate and reliable evaluation of the environmental impact of industrial sites. The in-situ data can be complemented with statistical calculations about the carbon footprint of industry sites as well as cities. Municipal and national governments, NGOs, corporates, and research institutes can leverage this information in conjunction with carbon accounting, GHG measurements, and climate impact assessments for a cleaner, brighter tomorrow.