Carbon labeling and LCA

July 12, 2011 at 7:11 am Leave a comment

I just presented at the 44th  Annual Convention of the Australian Institute of Food Science and Technology  in a session on carbon labeling. My topic was ‘Life Cycle Assessment and Carbon Footprints’. I asked whether carbon footprints are a good thing and how they relate to LCA.

A Good Thing –  absolutely. We moan about the limited scope, but carbon footprints are bringing life cycle to the masses in ways LCA never could, nor perhaps should.

Three LCA questions arise from the broad scale adoption of carbon footprints:

1. Is carbon (read climate change) special?

More special than the other 17 impact areas used in LCA? (See recipe method for these.) Yes – for two reasons:

  • Carbon is the building block of organic matter and the principal component of fossil fuels, which are central to the transformation of material in the modern industrial economy. Carbon is everywhere and used by everything, making substitution and alternative uses very difficult.
  • The impact of climate change is not localised but represents a shift in so many global systems with such widespread and as yet unknown consequences that acid rain will look like a tea party.

2. Are carbon footprints a good proxy?

Yes – for energy, and energy is a great proxy for many other impacts. Some authors have looked at the correlation of energy and the ecoindicator 99, a broad-based environmental indicator, and shown that it is a good predictor for many sectors. Energy in its many forms more often than not dominates indicators such as:

  • acidification (acid rain – through sulphur and nitrogen oxide emissions)
  • eutrophication (algae growth – through nitrogen oxide emissions)
  • human and eco-toxic indicators (through the many metals and organic compounds emitted from fuel combustion)
  • solid waste (through coal ash production).

To a lesser extent, it can be a major water user (for cooling in coal-fired power stations) and land user (for hydro reservoirs, transmission lines and road networks for transport). But these tend to be swamped by agricultural uses (excuse the pun).

3. When will carbon footprints not align and possibly compete with other indicators?

Some indicators are not related to energy and greenhouse gases (GHGs) in particular product systems. These include ozone depletion, nutrient runoff from agriculture, toxic emissions from fertiliser application or processes which generate toxic emissions through water processes. End-of-pipe pollution control normally involves additional energy and GHG impacts to reduce or contain toxic emissions, be they metals, nutrients or other polluting substances.  However, the most important tension is between GHGs, land use and water use. Land can be used to sequester carbon or produce fuels which avoid the need to consume and burn fossil fuels (effectively reducing carbon emissions). Water can be used to increase the productivity of land, allowing it to produce more biomass and so avoid more fossil fuels. Water extraction from the environment can be avoided through the recycling of water or the production of desalinated water, both of which will come with increased GHG impacts. So water, land and GHGs are three limiting connected factors which need to be balanced, with land and water physically constrained by the planet, and GHG constrained by the planet’s ability to cope with its emissions.

If the carbon footprint label needs one key innovation, it would be a ‘no additional land or water use’ test.

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