Is it better to eat tomatoes grown in electrically powered greenhouses, or to opt for produce imported from sunnier climes?
Initially reports suggested that the transported tomatoes were preferable from a carbon footprint point of view. However, supporters of the greenhouse option countered that they used fewer pesticides and less water in their controlled environment, and in fact supplied power back to the grid.
And so the debate continues...
This example, used by Dr Philipa Notten from The Green House consultancy, points to just how complex it is to pin down exactly how sustainable a product is. Companies and consumers should not make decisions based on just one factor, such as carbon. When you start considering the by-products and co-products of a system, things get even more complicated.
Using a lifecycle assessment (LCA) of the South African dairy industry, Dr Notten set out to show that LCA, carried out correctly, can provide a systematic assessment of a product supply chain and debunk some sustainability myths we take for granted. The dairy industry LCA was carried out on behalf of WWF South Africa and presented to the industry at the first FACTS (Food and Allergy Consulting and Testing Service) and WWF Food Industry Workshop held in Cape Town.
The aim of an LCA is to review the environmental impact of all stages of a product and identify the elements of the supply chain that cause the most harm, in order to equip decision-makers with the knowledge to assess, manage and improve their supply chains. It does this by making an inventory of all inputs and outputs of each stage of a pre-defined supply chain, assessing the knock-on effect within the context and then providing an interpretation that can be used in setting strategy and decision-making.
For example, a power station might be concerned about its sulphur dioxide emissions into the atmosphere and consider using a water disposal system instead. However, an LCA would show the impact of this ‘improvement’ in a wider context. For instance if the power station is located in a water-threatened area, this could be a poor choice rather than an improvement.
The fresh milk study compared the sustainability of a range of dairy farms, from large to small, using both pasture-based and intensive-farming methods. It considered all aspects of dairy farming, including the feed brought in, farming methods, power used, transport, packaging and consumption, in an attempt to offer a scientific basis for decision-making.
Some surprising results included that, as we reported in last month’s Beverage Review, although packaging only contributes four to six per cent of the total carbon footprint of the milk production lifecycle, it has the largest influence on the rest on the rest of the lifecycle compared to any other stage from the farm to the consumer.
For instance, the carbon footprint of a container is equivalent to that of 1.5 tablespoons of milk inside the container when you factor in all the processes needed to get the milk to a packaged state. In addition, waste that takes place later in the lifecycle of milk has a higher carbon footprint: wasting one litre of milk at home is equivalent to wasting two litres at the farm.
‘We should worry about what’s in the bottle, rather than the bottle itself,’ said Dr Notten. So although popular wisdom might suggest that buying in bulk is more environmentally friendly, thanks to less packaging being used, in the context of the entire lifecycle of milk, the reduction in waste by consuming milk in smaller quantities vastly outweighs the benefits of less packaging.
Unsurprisingly, organic farming scored lower than more intensive, industrialised farming owing to the methane produced by pasture-fed cattle. ‘The organic movement is not much of a fan of LCA,’ said Dr Notten. This does point to some of the limitations of the LCA methodology in that it sets out to measure some very specific things, and does not, amongst other things, take animal welfare into consideration.
Developed and popularised in northern Europe, traditional LCAs do not take land and water impacts into account, and Dr Notten is working to extend the model to include land and water indicators in order to be more relevant to countries such as South Africa.
For instance, in South Africa, a country that suffers from water shortages, agriculture accounts for 60 per cent of water usage. According to Dr Notten, 1 000 litres of water goes into making one litre of milk. Agriculture also has an impact on bio-diversity. So, decisions relating to land and water can have a profound impact on the overall LCA.
When it comes to land and water, where the dairy farms’ cattle feed was produced became significant, to such an extent that when feed was included in the assessment, intensive and pasture dairy farms came out equal. The Northern Cape is the optimal place to source feed from, the region has both good water, and the feed production makes less of an impact on bio-diversity.
Other results showed the retail segment fared poorly in the overall LCA owing to its reliance on coal-based power sources in South Africa. The consumer portion of the LCA, which is often left out, showed that 93 per cent of consumers use a car to purchase milk, and only 19 per cent buy milk on the way to or from somewhere else. This causes the consumer to have as high an impact as the processing plant, between two and 13 per cent of the total.
The distribution link in the fresh milk supply chain performed well, owing to the fact that vehicles transporting milk are normally packed to capacity. Packaging has a role to play here, with the development of light yet hardy packaging that can be stacked without wasting space.
The LCA model is not without its critics. Concerns include that practitioners can engineer an assessment to come up with the ‘right’ results. An LCA is also only as good as the data input, errors here can lead to misleading results.
The outcome of an LCA should not be used for comparative marketing purposes, according to the ISO 14000 guidelines, although some companies have done this in the past. ‘There are significant pitfalls with trying to come up with a single, defensible, reproducible number,’ said Dr Notten.
Used correctly, an LCA can provide companies with significant insight into the sustainability of their activities, clarity on what the big wins and trade-offs are, as well as a useful internal benchmark to measure their progress.
