Peer review of metrics

During 2011 we invited a panel of lifecycle analysis experts led by Professor Roland Clift to review our approach to measuring and reducing our environmental impacts, including the key metrics we use to measure progress on our Sustainable Living Plan.

Independent Review

The purpose of this exercise was to assess the robustness, relevance, quality and completeness of our approach, including the way in which we set our targets and communicated the results.

The Panel conducted a scientific review of the three metrics for greenhouse gas emissions, water and waste per consumer use (referred to as the ‘Less Environmental Impact’ programme). It looked in particular at the scope and boundaries of the metrics, the validity of calculation methods, assumptions and data sources.

Peer Review Panel: Statement

The scientific and technical Peer Review Panel, whose members are listed below, has examined the metrics and baseline proposed by Unilever to support development and monitoring of the Less Environmental Impact (LEI) programme.

We consider Unilever’s approach to be sound and appropriate. Unilever has selected a set of impacts which are relevant to describing the lifecycle environmental impacts of the company’s businesses and products. The baseline data provide a representative picture of current performance in terms of these impacts, and consistent application of the approach should give a sound indication of progress towards the targets the company has set.

During the review, we identified a number of aspects of the LEI approach where further clarification was needed. The way in which our questions were answered was one of the features that encouraged our confidence in endorsing the approach. We have made a number of recommendations to improve the clarity and transparency of the process.

We hope and expect that Unilever will publish our detailed review and respond to the questions raised, and set up a mechanism to enable answers to be provided to other scientific and technical questions which might arise in future.

We also note that Unilever will need an ongoing work plan to ensure that evolution of the metrics and the measurement process continue to reflect current best practice and scientific rigour, and to verify progress against the targets set out in the LEI Plan.

Professor Roland Clift, University of Surrey, UK

Professor Matthias Finkbeiner, Technical University of Berlin, Germany

Dr Mark Goedkoop, Pré Consultants, Netherlands

Professor Sarah McLaren, Massey University, New Zealand

Stuart Orr, WWF, Switzerland

Peer Review Panel: Observations & recommendations

The Panel has published a report setting out its observations and recommendations. See the download for more. We are in the process of publishing our footprinting approach and this will address a number of the points highlighted in the peer review. The publication will be made available on this site together with our response to the peer review recommendations.

Measuring our progress

Our Sustainable Living Plan has three big goals to improve health and well-being, reduce environmental impact and enhance livelihoods. Supporting these goals are seven commitments underpinned by targets spanning our social, environmental and economic performance across the value chain.

In our 2011 Progress Report we presented our people and workplace targets as a standalone set of targets. In 2012 we incorporated these targets into the main body of the plan.

How we define our metrics

Our environmental footprint per consumer use

To measure our big goal to halve the environmental footprint of the making and use of our products ‘per consumer use’* for GHG, water and waste is a complex process. It requires a detailed analysis of the water, waste and greenhouse gas impacts of thousands of products spread across 14 countries. The calculation accounts for 70% of our volumes.

For each product, we analyse sourcing and ingredient information, manufacturing impacts and data on consumer habits (which often vary by country).

In 2012 we invested in an automated system to improve the speed and accuracy of our footprint calculations, which we measure on a rolling-year basis from 1 July to 30 June. Currently, this system only allows us to compare our footprint to 2010 rather than our original 2008 baseline.

Health and hygiene

The number of people reached on a cumulative basis by an intervention which, based on past studies, can be expected to result in sustained, positive behaviour change.


The percentage of products which meet the highest nutritional standards, based on globally recognised dietary guidelines for all four priority nutrients: salt, saturated and trans fat and sugar. From 2012, these are measured by volume rather than by product.

Greenhouse gases

Greenhouse gases per consumer use: CO2 equivalents across the product lifecycle (grams).*

Our metric measures the greenhouse gas emissions associated with the lifecycle of a product from raw materials, to manufacturing to consumer use and disposal.


Water per consumer use in water-scarce countries: water added to the product plus the water used by consumers in waterscarce countries (litres).*+ Our metric excludes water used in agriculture, and water used in our manufacturing operations which we measure as part of our eco-efficiency programme (see Reduce water use in our manufacturing process).


Waste per consumer use: packaging and product leftovers that have not been reused, recycled or recovered (grams).*

We define waste as the amount of product left in the pack, and the amount of packaging that ends up either in landfill or as litter, ie the amount of packaging that is not recycled, reused or recovered for energy recapture. Our metric requires the use of published national indices for recycling and recovery, or our own estimates where these are not available.

The metric excludes the waste generated by our manufacturing operations which we measure as part of our eco-efficiency programme (see Reduce waste from our manufacturing).

Sustainable sourcing

Raw or packaging material sourced from verifiable sustainable renewable sources or made from recycled materials (% by weight).

Better livelihoods

We recognise that it is difficult to provide evidence of improvements in livelihoods. We are developing an appropriate methodology to do this.

* The metrics for our commitments for greenhouse gases (GHG), water and waste are expressed against a baseline of 2008 and on a ‘per consumer use’ basis. This means a single use, portion or serving of a product, eg the GHG impact of drinking a single cup of tea; the water needed for one hair wash with shampoo; or the waste associated with one serving of soup.

+ Water-scarce countries: China, India, Indonesia, Mexico, South Africa, Turkey and USA, representing around half the world’s population.