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PARALLEL SESSION 2A: LAND USE 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
Peri-urban expansion: application of consequential LCA to assess land
for food or housing
Alison Rothwell 1 , Brad Ridoutt 2 , Girija Page 1 , Bill Bellotti 1
1 University of Western Sydney, School of Science and Health, Locked Bag 1797, Penrith, NSW 2751, Australia
2 Commonwealth Scientific and Industrial Research Organisation (CSIRO), Sustainable Agriculture National Research Flagship,
Private Bag 10, Clayton South, Victoria 3169, Australia
Corresponding author. E-mail: alison.rothwell@uws.edu.au
ABSTRACT
Competing land uses such as urban expansion are impacting fresh food production in peri-urban Sydney. Providing both housing and
fresh food at lower relative emissions rates should be a priority in policy development. This paper presents a method that enables a
comprehensive view of environmental trade-offs at the urban-agricultural intersection. Using consequential LCA, global warming
potential (GWP) was calculated for two peri-urban land use scenarios involving two distinct types of urban housing systems whilst
accounting for agricultural diversity at the farm scale. In Scenario 1 Sydney’s horticultural production was displaced by low density
outer suburban housing. Scenario 2 involved retention of Sydney’s horticultural production with an infill housing model. Results
show that although differences were observed within the agricultural system, it is the urban housing system dominating GWP impacts,
with scenario 1 having a GWP 74 t ha -1 higher than for scenario 2. Policy focus on urban housing systems for greenhouse gas
abatement in the regional context is recommended.
Keywords: food security, lettuce, greenhouse gas emissions, land use change, urban development.
1. Introduction
This paper describes the use of consequential LCA (CLCA) to assess land use options at the agricultureurban
interface. Competing land uses such as urban expansion are impacting fresh food production in periurban
Sydney (Australia). Research is divided regarding the status of peri-urban horticultural land management
in the Sydney basin. Although many qualitative papers on the benefits of peri-urban agricultural land
retention exist both nationally (Choy et al., 2008; Houston, 2005) and internationally (Condon et al., 2010;
van Veenhuizen and Danso, 2007), quantitative, evidence based planning is predominantly absent. Although
the value of production for vegetables in the Sydney basin represents approximately 46% of the NSW state
total, at only 6% of the value of Australian production (ABS, 2010), proponents of urban development argue
that Sydney’s horticultural production is of little consequence. Urban development is politically and economically
well supported. Government policies are trending in favour of development for urbanisation
(NSW Department of Planning, 2010) with the number of horticultural farms in Sydney anticipated to halve
under current planning policy (ARUP, 2010b). If this trend continues, horticulture may cease as a viable
land-use and economic function in the Sydney basin. Sydney’s balance of horticultural produce will then be
imported from regional locations. It is not known, however, if the alternative food producing locations present
a more or less sustainable environmental situation for vegetables on the Sydney market compared with
local production. While there is a need to provide housing, opportunity exists for a data driven methodology
to evaluate the environmental consequences of the decision to urbanise, for the purpose of informing policy
and driving greenhouse gas (GHG) emissions abatement.
Australia currently exhibits the highest GHG emissions of any OECD country per capita, with average
emissions exceeding four times the world average (Garnaut, 2008). Suburban residential development is a
key contributor to these emissions, with differences reported in environmental impacts between different
urban forms, notably between more energy intensive car reliant low-density outer urban greenfield style
housing development versus lower energy intensive, infill development of inner suburban areas with existing
public transport infrastructure (ARUP, 2010a; Camagni et al., 2002; Duffy, 2009; Fuller and Crawford,
2011). Despite this, urban expansion into new greenfield areas is the accepted norm for new housing development,
with resistance to implementing higher density infill housing along key transportation corridors in
established suburbs. Providing both housing and fresh food at lower relative GHG emissions rates should be
a priority in policy development. The contradictory stance and poor integration between policy direction on
emissions and metropolitan planning has been highlighted (ARUP, 2010b). Agricultural emissions are also
known to be high relative to other OECD countries (Garnaut, 2008). Both agriculture and urban systems
have differing and relatively large environmental impacts. At the peri-urban interface, what do the combined
environmental impacts look like under different peri-urban land use scenarios?
Consequential LCA (CLCA) provides a methodology that can assess environmental impacts relating to
using land for housing versus land for food, and assist answering the question “What are the environmental
consequences of urbanising Sydney’s horticultural lands?” Should peri-urban land be seen as land in waiting
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