Carbon targets are useful because they focus attention. A business that sets out to reduce its emissions will look harder at materials, energy, transport and packaging, and will often find genuine improvements. But focus has a side effect. When one number dominates decisions, teams start optimising around it, and outcomes that matter just as much but receive less attention can quietly get worse.
A material with lower embodied carbon may need more energy to cure or may not last as long. A fuel additive that cuts one pollutant may increase another. A lighter packaging format may reduce emissions per pack while increasing food waste. Each of these is a case of burden shifting: an improvement in the measured outcome bought by a deterioration somewhere else, in a different impact, a different stage of the product’s life, a different part of the supply chain or a different organisation.
This article explains how burden shifting happens, why comparing options per unit of useful function matters, how to make trade-offs explicit and how a small business can apply these ideas to everyday decisions about materials, energy, packaging and suppliers. The aim is not to weaken decarbonisation. It is to make sure that improvements are real.
Where burdens shift to
Burden shifting takes several forms:
- Across environmental impacts: lower carbon but higher water use, toxicity, land use or other air pollutants.
- Across performance: lower carbon but shorter life, lower strength, lower efficiency or more maintenance.
- Across life-cycle stages: lower manufacturing impact but higher impact in use or at end of life.
- Across boundaries: outsourcing an activity removes it from your figures, but the impact continues at the supplier.
- Across places: impacts move to a different region or country.
- Across time: a short-term reduction creates a long-term problem, such as a material that is hard to recover at end of life.
None of these is automatically wrong. Some trade-offs are worth making. The problem is hidden trade-offs that nobody chose deliberately.
What the research shows
Published engineering research gives clear examples. Studies of concrete made with recycled concrete aggregate and fly ash found that the best combined result for strength and global warming impact came from the right combination of the two materials rather than from maximising either one. Studies of alternative cement-free binders using waste-derived ingredients found lower global warming impact than conventional cement in the cases studied, but higher impacts in some other environmental categories, with heat curing and some chemical ingredients contributing significantly. Engine research on biodiesel additives found that one additive cut nitrogen oxide emissions more strongly while increasing unburnt hydrocarbons and carbon monoxide, and another improved efficiency while changing the emissions profile differently.
None of these studies argues against reducing carbon. Together they show that engineering decisions need a goal broader than one environmental number. Variables are coupled: changing a binder changes strength and impact together, and changing a fuel changes efficiency and several pollutants together.
Compare per unit of function
The most common source of misleading comparisons is the wrong unit. Comparing materials per kilogram, or packaging per item, ignores how much is needed and how well it does the job. A functional unit describes the useful service being delivered, so options can be compared on an equal footing. Examples:
- Square metres of flooring over a defined service life.
- Kilograms of product delivered to customers and eaten before it spoils.
- Tonne-kilometres of freight moved.
- Litres of water treated to a required quality.
- Parts manufactured within specification.
- Structural capacity over a design life.
A lower-carbon binder that needs twice the thickness to carry the same load, or a coating that must be reapplied twice as often, may be worse per unit of function even if it is better per kilogram. Insist that every comparison states its functional unit, and that the unit represents the decision actually being made.
Interfaces and margins
Two further engineering points matter.
First, substitutions change systems at their interfaces. A recycled aggregate changes how concrete behaves. A new resin changes adhesion and curing. A lighter component changes vibration and wear. The benefit claimed for a substitute can be lost where it meets the rest of the system, so validate the whole system, not just the component.
Second, look at margin and variability, not just averages. A lower-carbon option that only just meets a requirement in the laboratory may need tighter quality control, produce more rejects or require a more conservative design in practice. Those consequences can cancel both the environmental and the economic gain. An option with similar average performance but much wider uncertainty, especially about durability, deserves a pilot or a limited first application rather than full adoption.
Reversibility matters
Some decisions are easy to reverse: a packaging supplier, a cleaning chemical or a delivery route. Others are hard: a material built into a long-life asset, a process built into a factory layout or a long-term supply contract. A small environmental advantage based on weak evidence may justify an easily reversed trial. It rarely justifies an irreversible commitment. Weigh the strength of the evidence against how hard the decision would be to undo.
A multi-objective decision method
For significant decisions about materials, processes, energy or packaging, work through eight steps:
- Define the required function: what must the option do, under what conditions, for how long?
- Set non-negotiable thresholds: safety, legal compliance, minimum performance, quality and critical environmental limits.
- Choose the material metrics: include carbon, plus any other impacts that could plausibly change the decision, such as water, waste, toxicity or local air quality. Do not measure everything just because data exists.
- Normalise by function: compare on an equal service basis, including quantity, life and replacement.
- Map interactions: identify where improving one variable changes another. Use evidence where consequences are material.
- Test interfaces and process needs: curing, mixing, compatibility, equipment, maintenance and quality control.
- Assess uncertainty and reversibility.
- State the trade-off: what gets better, what gets worse and why the trade is acceptable.
If nothing appears to get worse, the analysis may be incomplete.
The burden-shifting statement
A simple discipline is to require every significant “lower carbon” proposal to include a short statement covering the main metrics. It can fit in one table:
| Metric | Direction | Approximate size | Evidence | Why acceptable |
|---|---|---|---|---|
| Carbon per functional unit | Better | Moderate | Supplier data, own calculation | Primary objective |
| Service life | Unchanged | — | Pilot results | — |
| Water use | Worse | Small | Supplier data | Site not water-constrained |
| Cost per functional unit | Worse | Small | Quotes | Within budget, offset by customer demand |
| Waste at end of life | Better | Moderate | Recycler confirmation | Supports recycling commitments |
The statement makes trade-offs visible and forces the team to look for them. It also gives managers something concrete to challenge.
Choosing between several projects
Burden shifting also shows up when a business chooses between several improvement projects. Ranking projects only by tonnes of carbon avoided per dollar is simple, but it can favour projects that look good on paper while neglecting others that matter more over time. One project may cut a large amount of carbon cheaply but build no capability. Another may deliver a smaller immediate reduction while laying groundwork, such as electrical capacity, data or skills, that deeper improvements will need. A third may reduce energy use in operation while increasing the impact of the materials it is built from.
When comparing projects, consider alongside carbon:
- Cost per unit of functional improvement, not just per tonne.
- Reversibility and how hard the project would be to undo.
- Maturity of the technology or method.
- Regulatory and customer exposure.
- Resilience, such as reduced dependence on a single supplier or energy source.
- New dependencies the project creates.
- Capability built for future projects.
- Burdens shifted to other impacts, stages or organisations.
This does not need a complicated scoring model. A short discussion of these points for each shortlisted project, recorded alongside the numbers, is usually enough to stop a simple ranking from steering the business in the wrong direction.
A worked example
This is an illustration. A small food manufacturer sells chilled ready meals in plastic trays. To reduce its packaging footprint, the business considers switching to moulded fibre trays, which have lower carbon per tray according to supplier data.
A tray-by-tray comparison looks decisive:
- Plastic tray: about 40 g CO2e per tray (illustrative).
- Fibre tray: about 25 g CO2e per tray, 37.5% lower.
But the functional unit is not a tray. It is a meal delivered to a customer and eaten. Trials show the fibre tray with the available lid seal gives a shorter shelf life, increasing the share of meals that spoil unsold or uneaten. Each meal’s ingredients, cooking and chilled transport carry an illustrative footprint of about 1,000 g CO2e, far larger than the tray.
| Option (illustrative) | Footprint per pack made | Share spoiled | Footprint per meal eaten |
|---|---|---|---|
| A: Plastic tray | 1,040 g | 3% | 1,040 ÷ 0.97 ≈ 1,072 g |
| B: Fibre tray, standard lid | 1,025 g | 8% | 1,025 ÷ 0.92 ≈ 1,114 g |
| C: Fibre tray, improved seal | 1,028 g | 4% | 1,028 ÷ 0.96 ≈ 1,071 g |
Option B, which looked best per tray, is the worst per meal eaten, because extra spoilage outweighs the packaging saving. Option C, a fibre tray with a better seal, is about equal to plastic on carbon per meal eaten, and the business values reducing plastic use, so it proceeds with a pilot of option C. Its burden-shifting statement records that carbon per meal is about the same, plastic use falls, cost per pack rises slightly, and end-of-life outcomes depend on whether customers’ local facilities accept the tray, which the business will check before making any claims about it.
The business also asks the tray supplier for evidence that the tray and its coating are suitable for food contact, and confirms its own obligations with its food regulator.
How this applies to a small Australian business
Small businesses make burden-shifting decisions all the time: choosing packaging, materials, suppliers, vehicles, cleaning products and equipment. Practical steps:
- Define the functional unit before comparing options.
- Ask suppliers for data on more than carbon, including service life, maintenance and end-of-life options.
- Include the full life: purchase, use, maintenance, replacement and disposal.
- Watch outsourcing: moving an activity to a supplier removes it from your figures but not from the world. If you report emissions or make claims, be clear about boundaries.
- Pilot before committing where evidence is uncertain or the decision is hard to reverse.
- Write a short burden-shifting statement for significant decisions.
- Keep claims accurate: under the Australian Consumer Law, environmental claims must be truthful and supportable. The ACCC publishes guidance on making environmental claims.
The articles on sustainability as an operating choice and qualifying recycled materials for real products cover related decisions.
Signals worth watching
- Carbon reductions accompanied by shorter service life or more maintenance.
- Rising water, chemical or energy use in processing.
- Increases in waste, spoilage or rejects.
- Lower purchase price but higher cost over the life.
- Reported figures improving after outsourcing while the total activity is unchanged.
- Teams unable to explain the functional unit behind a comparison.
- Rankings that change sharply when durability or replacement is included.
Common mistakes
- Treating carbon as a complete measure of environmental performance.
- Comparing per kilogram or per item rather than per unit of function.
- Assuming environmental and technical performance are independent.
- Letting different teams optimise different metrics with no one integrating them.
- Claiming reductions that are really transfers to suppliers.
- Committing irreversibly on weak evidence.
- Hiding trade-offs rather than stating them.
Frequently asked questions
Does this mean we should not pursue carbon targets? No. Carbon targets remain important. This approach makes reductions more credible by checking that they are not purchased at a hidden cost elsewhere.
How many metrics should we track? Only the ones that could change the decision. For most small-business decisions, carbon plus two or three others, such as cost per functional unit, service life and waste, is enough.
What if a trade-off is unavoidable? Many are. State it, explain why it is acceptable and monitor it. Trade-offs are not failures. Hidden trade-offs are.
Questions to ask
- What function are we comparing, and are the options truly equivalent on that basis?
- Which impacts other than carbon could change this decision?
- What gets worse as our preferred metric improves?
- Have we included service life, maintenance, replacement and end of life?
- Is any reduction simply a transfer outside our boundary?
- How reversible is this decision if the evidence turns out to be wrong?
- What trade-off are we accepting, and why?
Bringing it together
A lower-carbon result is not automatically a better result if it is bought by shifting the burden into durability, other emissions, waste, cost or someone else’s operations. Compare options per unit of useful function, look for coupled variables and interface effects, weigh margin and variability alongside averages, and match the strength of evidence to how reversible the decision is. Above all, state the trade-offs. A business that can say clearly what improved, what worsened and why the balance is right will make better decisions and more credible claims.
Source: KEVOS notes, drawing on published engineering research on concrete, alternative binders, fuel additives and separation membranes. Figures in this article are illustrations, not data. This article is general information, not environmental, food safety or legal advice.
