February 9th, 2018

Measure for measure

5 minute read

by Rob Gillies and Eric Bridgwater


The UK Government has been hinting that, in a post-Brexit future, the UK might move away from weight-based recycling rates as the key measure of waste management environmental performance. So what alternatives are there, and why might they be preferable?


Weight and see

The most common criticism of weight-based recycling rate targets is that they don’t adequately incentivise making waste management interventions further up the waste hierarchy. There are good reasons to believe that the greatest environmental benefits come from waste prevention, but if you reduce the amount of recyclable material entering the market, you may make a weight-based target harder to hit. A high recycling target can incentivise maximising the collection of waste for recycling, when in the past some of that material might have been managed by householders. The main example is where local authorities collect garden waste for municipal composting: this seems not to simply divert waste from the residual stream but also draws in waste that people in the past might have composted at home.

So, what should we be looking for in an alternative? Ideally it would better incentivise action in line with the waste hierarchy and circular economy principles, and incentivise reductions in the greenhouse gas (GHG) emissions associated with waste management. It would also be helpful if an alternative measurement method can be considered fair across different local authority types, in terms of socio-demographics and geography, and of course it needs to be practicable. If it relies on data that are difficult to collect, or very complex calculations and metrics, it may prove impossible to implement or difficult to explain or justify to non-experts.


Metric system

A range of possible alternative measures of performance could be considered:

  • Percentage of waste landfilled (less being better);
  • Total waste arisings (less being better);
  • Residual waste per household or capita (less being better);
  • GHG emissions-related measures such as:
    1. GHG impact per tonne of waste managed;
    2. Percentage of total potential GHG savings achieved (measured as GHG savings from recycling collection, compared to the maximum possible GHG savings if all collected waste that was recyclable/compostable was in fact collected for recycling/composting); and
    3. GHG impact per person (for household waste).


Many of these measures have already been used. Eunomia already publishes a GHG metric in the form of our Recycling Carbon Index. This metric focuses on the GHG emissions saved as a result of recycling, and therefore highlights the differential benefit of collecting and recycling materials according to their GHG impacts. There is also precedent for a measure of GHG performance per tonne of waste managed, in the form of the Mayor of London’s Emissions Performance Standard, which Eunomia helped to develop. However, neither of these approaches provides an inducement or incentive to prevent waste.


Tape measure

How do different waste management metrics measure up? Photo: Sean MacEntee (CC BY 2.0), via Flickr.


Zero Waste Scotland’s Carbon Metric is an example of an overall embodied carbon metric. As well as quantifying the carbon benefit of recycling, it also takes account of waste prevention. While Scotland still uses a tonnage-based target, this metric allows the Scottish Government to track performance in a different way, which is sensitive to prevention and recycling in equal measure. However, preparing it is a relatively painstaking process, requiring regular research and updates to keep up to date with the changing GHG impacts of the production and treatment of materials.


For good measure

Our analysis of the available measures of performance concluded that the most favourable metrics would be:

  • amount of residual household waste per person per year; and
  • GHG emissions (expressed as CO2 equivalent emissions per person per year).


The former incentivises waste prevention as well as recycling, focusing on preventing material from leaking out of the circular economy. It is being ever more widely used in other parts of Europe, particularly in Italian municipalities and in Belgium, and is the performance measure of choice for Zero Waste Europe.  It is well understood by local authorities and easy to communicate to residents.

Although more complex to calculate and susceptible to fluctuations due to factors that aren’t directly related to changes in waste management, the advantage of the GHG emissions metric is that it more closely approximates to the environmental benefit achieved through waste management. The calculation would consider a) the embodied GHG emissions of what is consumed and b) the offsetting benefits associated with recycling of that waste that is generated. This provides an incentive to manage waste in ways that help achieve the best overall environmental performance.

Better still might be the use of a ‘dashboard’ of indicators, incorporating several measures. One could be treated as the lead indicator, while the others enable local authorities to consider – perhaps focusing on their own performance over time, rather than comparing with the performance of others – where there is scope for improvement.

Brexit means there is a degree of uncertainty about whether (or at least, for how long) the UK will sign up to the new EU recycling targets. Now is as good a time as any to consider which alternative measures of performance would more properly incentivise improvements in waste management performance in the future. There’s nothing to stop us from adopting alternative metrics alongside any tonnage-based target for recycling, and taking waste management in a direction that the EU might want, in due course, to consider following.


Rob Gillies and Eric Bridgwater



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Janet Rawlings
Janet Rawlings

Wouldn’t the GHG Emissions target penalise incineration?
Are there an internationally agreed set of GHG emission values for materials? I could see renewable energy versus fossil fuel energy use in production and recycling processes being used to skew the figures.

Peter Jones

Hi Janet, Shlomo, Good questions – and ones that are very difficult to answer in the abstract. Broadly, for a GHG approach to work, the UK would need to come up with a set of carbon factors that reflect how the materials we use are produced, and the carbon impacts of waste treatments. So, what might they look like? Shlomo – you’ll already be familiar with the factors that would decide how EfW plays out: what is the composition of the incinerated waste? What assumptions are made about the displaced sources of electricity? How is landfill assumed to perform? The… Read more »

Shlomo Dowen

Would incineration be penalised or rewarded? How might a GHG-based metric handle biogenic carbon??