Life Cycle Assessment of Supermarket Carrier Bags: a Review of the Bags Available in 2006
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Life cycle assessment of supermarket carrier bags: a review of the bags available in 2006 Report: SC030148 The Environment Agency is the leading public body protecting and improving the environment in England and Wales. It’s our job to make sure that air, land and water are looked after by everyone in today’s society, so that tomorrow’s generations inherit a cleaner, healthier world. Our work includes tackling flooding and pollution incidents, reducing industry’s impacts on the environment, cleaning up rivers, coastal waters and contaminated land, and improving wildlife habitats. This report is the result of research commissioned and funded by the Environment Agency. Published by: Author(s): Environment Agency, Horizon House, Deanery Road, Bristol, Dr. Chris Edwards BS1 5AH Jonna Meyhoff Fry www.environment-agency.gov.uk Dissemination Status: Publicly available © Environment Agency Keywords: February 2011 Carrier bags, life cycle assessment, LCA ISBN: 978-1-84911-226-0 Research Contractor: All rights reserved. This document may be reproduced with prior Intertek Expert Services permission of the Environment Agency. Cleeve Road Leatherhead, KT22 7SB The views expressed in this document are not necessarily those of the Environment Agency. Tel 01372 370900 This report is printed on Cyclus Print, a 100% recycled stock, Environment Agency project manager: which is 100% post consumer waste and is totally chlorine free. Dr Joanna Marchant Water used is treated and in most cases returned to source in Environment Agency better condition than removed. Kings Meadow House Kings Meadow Road Further copies of this report are available from: Reading, RG 1 8DQ The Environment Agency’s National Customer Contact Centre by emailing [email protected] or by Tel 0118 9535346 telephoning 08708 506506. Product Code: SCHO0711BUAN-E-E Evidence at the Environment Agency Evidence underpins the work of the Environment Agency. It provides an up-to-date understanding of the world about us, helps us to develop tools and techniques to monitor and manage our environment as efficiently and effectively as possible. It also helps us to understand how the environment is changing and to identify what the future pressures may be. The work of the Environment Agency’s Evidence Directorate is a key ingredient in the partnership between research, guidance and operations that enables the Environment Agency to protect and restore our environment. This report was produced by the Research, Monitoring and Innovation team within Evidence. The team focuses on four main areas of activity: • Setting the agenda, by providing the evidence for decisions; • Maintaining scientific credibility, by ensuring that our programmes and projects are fit for purpose and executed according to international standards; • Carrying out research, either by contracting it out to research organisations and consultancies or by doing it ourselves; • Delivering information, advice, tools and techniques, by making appropriate products available. Miranda Kavanagh Director of Evidence Advisory Board This project was informed and assisted by an Advisory Board set up by the Environment Agency. Iris Anderson Department of Energy and Climate Change (DECC) Peter Askew Department for Business, Innovation and skills (BIS)1 Jane Bickerstaffe Industry Council for Packaging and the Environment (Incpen) Terry Coleman (Chair) Environment Agency Jeff Cooper Environment Agency2 Julia Faria Local Environmental Quality Division, Department for Environment, Food and Rural Affairs (Defra)2 Bob Gordon British Retail Consortium (BRC)3 Keith James Waste & Resources Action Programme (WRAP)4 Marlene Jannink Department for Business, Enterprise & Regulatory Reform (BERR)5 Charlotte Lee-Woolf Sustainable Consumption and Production, Department for Environment, Food and Rural Affairs (Defra)3 Joanna Marchant Environment Agency Rob Mynard Waste Strategy Division, Department for Environment, Food and Rural Affairs (Defra)2 Julie Osmond Welsh Assembly Government3 Marc Owen Waste Strategy, Department for Environment, Food and Rural Affairs (Defra)3 Gerry Newton-Cross Environment Agency6 Julian Parfitt Waste & Resources Action Programme (WRAP)7 Nigel Smith British Retail Consortium (BRC)2 1 From January 2007. 2 Until April 2007. 3 From December 2009. 4 From December 2006. 5 Until December 2006. 6 Until April 2007. 7 Until November 2006. Stakeholder Consultation Group In addition to the Advisory Board, a Stakeholder Consultation Group was set up to support the project. Membership of the Stakeholder Consultation Group was by invitation. The purpose of the Stakeholder Consultation Group was to provide a two-way communication platform. Executive Summary This study assesses the life cycle environmental impacts of the production, use and disposal of different carrier bags for the UK in 2006. In recent years, the relative environmental impacts of lightweight carrier bags and other options has been debated. By the Spring of 20098 leading supermarkets had halved the number of single use carrier bags used. However, questions still remain about the environmental significance of lightweight carrier bags, especially with regard to the wider debate on global warming. The report considers only the types of carrier available from UK supermarkets9. It does not examine personal bags nor carriers given out by other high street retailers. The report does not consider the introduction of a carrier bag tax, the effects of littering, the ability and willingness of consumers to change behaviour, any adverse impacts of degradable polymers in the recycling stream, nor the potential economic impacts on UK business. The following types of carrier bag were studied: • a conventional, lightweight carrier made from high-density polyethylene (HDPE); • a lightweight HDPE carrier with a prodegradant additive designed to break the down the plastic into smaller pieces; • a biodegradable carrier made from a starch-polyester (biopolymer) blend; • a paper carrier; • a “bag for life” made from low-density polyethylene (LDPE); • a heavier more durable bag, often with stiffening inserts made from non woven polypropylene (PP); and • a cotton bag. These types of carrier bag are each designed for a different number of uses. Those intended to last longer need more resources in their production and are therefore likely to produce greater environmental impacts if compared on a bag for bag basis. To make the comparison fair, we considered the impacts from the number of bags required to carrying one month’s shopping in 2006/07. We then calculated how many times each different type of carrier would have to be used to reduce its global warming potential to below that for conventional HDPE carrier bags where some 40 per cent were reused as bin liners. Finally the carriers were compared for other impacts: resource depletion, acidification, eutrophication, human toxicity, fresh water aquatic ecotoxicity, marine aquatic ecotoxicity, terrestrial ecotoxicity and photochemical oxidation (smog formation). 8 Based on 2006 baseline figures. 9 The study also included a paper carrier bag which are generally not available from UK supermarkets. The study found that: • The environmental impact of all types of carrier bag is dominated by resource use and production stages. Transport, secondary packaging and end-of-life management generally have a minimal influence on their performance. • Whatever type of bag is used, the key to reducing the impacts is to reuse it as many times as possible and where reuse for shopping is not practicable, other reuse, e.g. to replace bin liners, is beneficial. • The reuse of conventional HDPE and other lightweight carrier bags for shopping and/or as bin-liners is pivotal to their environmental performance and reuse as bin liners produces greater benefits than recycling bags. • Starch-polyester blend bags have a higher global warming potential and abiotic depletion than conventional polymer bags, due both to the increased weight of material in a bag and higher material production impacts. • The paper, LDPE, non-woven PP and cotton bags should be reused at least 3, 4, 11 and 131 times respectively to ensure that they have lower global warming potential than conventional HDPE carrier bags that are not reused. The number of times each would have to be reused when different proportions of conventional (HDPE) carrier bags are reused are shown in the table below. • Recycling or composting generally produce only a small reduction in global warming potential and abiotic depletion. Type of carrier HDPE bag (No HDPE bag HDPE bag (100% HDPE bag secondary reuse) (40.3% reused as reused as bin (Used 3 times) bin liners) liners) Paper bag 3 4 7 9 LDPE bag 4 5 9 12 Non-woven PP 11 14 26 33 bag Cotton bag 131 173 327 393 The amount of primary use required to take reusable bags below the global warming potential of HDPE bags with and without secondary reuse Contents CONTENTS ......................................................................................................................6 Abbreviations ................................................................................................................10 1 INTRODUCTION.......................................................................................................11 1.1 Project background..............................................................................................11 1.2 The different types of carrier bags .....................................................................11 1.2.1