What does a carbon footprint actually mean

What does a carbon footprint actually mean?

An oft-mentioned issue of the food industry and its by-product leather is the carbon footprint of cattle rearing and meat production. By association, this is for obvious reasons affecting the perception of leather. Product category rules state that only a small fraction of animal rearing is to be attributed to the carbon footprint of leather, yet consumers are likely to view the two as interdependent. But if we really want to understand the environmental impact, we first need to understand what a carbon footprint actually is and what it constitutes.

Measuring the carbon footprint
Let’s start by clarifying what we actually talk about when we mention a carbon footprint. The definition would appear pretty clear-cut: it's the measure of the amount of greenhouse gases produced by a process, organization, or region (depending on what one wishes to measure) over a set period. The name itself implies a focus on carbon dioxide, which is one of the greenhouse gasses (GHG) directly linked to climate change, and often on the lips of activists, politicians, and journalists. Usually abbreviated and better known under its chemical formula CO2, it's not the only GHG around. GHG is used to indicate a multitude of gasses that affect global warming. CO2, however, is the one we often focus on with measurements and reporting. When organizations mention improvements or expected effects of implementing changing factors, this is also the case. A carbon footprint LCA (life cycle assessment) will tell whether a factor is contributing to the level of greenhouse gas or not (or to what level of contribution it is having). Every LCA of meat, milk, and leather, therefore, provides us with an estimate of the carbon footprint and helps to identify points of improvement. As the term ‘carbon’ suggests CO2, these results don't always provide you with a completely clear picture.

The Greenhouse effect
CO2 is not the only gas contributing to the greenhouse effect. Much like the glasshouses we use for growing crops and plants, this term describes the atmospheric effect where chemicals in gaseous form lock-in heat that is emitted from the earth. They act like a giant glass greenhouse: keeping warmth from escaping, the global temperatures gradually increase, which can have disastrous consequences in the long run for our planet, with extreme weather events, threats to the global food supply, acidification of the oceans and rising sea levels. Scientists argue that some effects are already showing, and recent data shows that the current GHG levels have dropped significantly as a result of slowed or halted business. Averting the long-term future requires limiting the average increase to below 2°C, which is a daunting task at best. Achieving this lofty goal requires change, and many industries have carefully adapted their methods over the last decades. The food industry is no exception, yet falls victim to a peculiar confusion about the terminology. Let's look into that.

The food industry and greenhouse gases
The main gases that contribute to the greenhouse effect are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and the gas groups hydrofluorocarbons (HFCs), and chlorofluorocarbons (CFCs). Water (H2O) is technically a greenhouse gas, but is not considered part of the problem. This clearly shows carbon dioxide is not the only building block of the greenhouse effect. That makes an important point because a lot of the current debate on environmental impact focuses on this confused notion of a carbon footprint seems explicitly to zone in the food industry and cattle rearing based on the idea that it produces a lot of CO2. There are indeed significant emissions from this process.

Animals do create emissions. It's important to note, however, that not each greenhouse gas contributes to the effect in the same manner, and cattle mostly emit methane (CH4), not CO2. Where CO2 lasts for at least 1000 years in the atmosphere, methane is broken down in just nine years. Part of this confusion stems from the use of a CO2 equivalent (CO2-e) to establish the warming potential of each gas, and the current calculation of Global Warming Potential (GWP) that assumes that all GHG have the same impact over the tame time period. This measurement method, unfortunately, excludes part of the insights needed to understand the impact of each industry fully, as explained in a recent paper (Lynch et al, 2020). The actual emissions of the food industry have been pretty consistent over time in recent years, as we'll explain below.

The type of measurement used for LCA analysis that is recognised as the model best suited to livestock farming is the Global Livestock Environmental Assessment Model (GLEAM) and is guided by the terminology defined in the Intergovernmental Panel on Climate Change (IPCC) forum, specifically IPCC (2006).

Food industry emissions and leather
What does all of this have to do with leather? A frequent argument against the use of leather focuses on the impact of cattle rearing for food. As a by-product from this process, leather is held accountable for a proportion of this footprint, not all of it. However, the rapid deterioration and recycling of methane in the atmosphere means that any gasses emitted by the current herds are stable as their emissions are consistent with herds of 10 years ago. Yet, smarter farming practices even have a reductive effect on the impact of cattle rearing, of which regenerative farming is a prime example as it helps fertilization of the soil. Fertile soil is home to a rich biodiversity of plants and microbes that pull excess carbon dioxide out of the atmosphere.

Experts have said that a reduction of meat and dairy consumption are potential contributors to pushing back against climate change, but completely discarding these food sources is another matter. In fact, there are far-reaching arguments concerning animal farming as an integral part of this fight for our planet. Because of that, the by-product leather will remain a resource widely available with distinct qualities that fits the mold of a circular economy.

References

  • Allen, M. R. et al. (2018I. A solution to the misrepresentations of CO2-equivalent emissions of short-lived climate pollutants under ambitious mitigation, npj Climate and Atmospheric Science vol. 1. Retrieved from: doi.org/10.1038/s41612-018-0026-8, accessed on 14 April 2020.
  • IPCC. 2006. IPCC Guidelines for national greenhouse gas inventories, Volume 4: Agriculture, forestry, and other land uses. IGES, Japan 
  • Leip A., Weiss F., Wassenaar T., Perez I., Fellmann T., Loudjani P., Tubiello F., Grandgirard D., Monni S. and Biala K. (2010). Evaluation of the livestock sector's contribution to the EU greenhouse gas emissions (GGELS) -final report, European Commission, Joint Research Centre.
  • Lynch, J., Cain, M., Pierrehumbert, R., Allen, M. (2020) Demonstrating GWP*: a means of reporting warming-equivalent emissions that captures the contrasting impacts of short- and long-lived climate pollutants. Environmental Research Letters, Volume 15, Number 4. Retrieved from: https://iopscience.iop.org/article/10.1088/1748-9326/ab6d7e, accessed on 14 April 2020.