From landfill to natural vegetation – An exploration of available land use LCIA models and application in a specific case

Abstract

Anthropogenic land use is of increasing concern due to its negative impacts on food security, ecosystem services and biodiversity. While most products and services lead to negative impacts from land occupation and transformation, some contribute to a positive transformation through active land restoration. Currently, several life cycle impact assessment models denoted as ‘land use’ exist, but transparency is limited with regard to the environmental problems they address. The purpose of this paper is to study the available LCIA models with respect to ecosystems and resources, from an LCA practitioner's perspective by testing the practical application of each model on a specific case and by assessing if and how the models address positive land transformation. 48 life cycle impact assessment (LCIA) models were identified. The scope and methodological foundation of the models were examined and compared. The practical application of nine models were then tested by assessing inert landfilling, including land restoration in the post-operation phase. The functional unit was treatment and landfilling of 1 tonne of inert hazardous waste. The life cycle stages include the transport of the waste, the neutralisation process, the operation of landfill and active restoration. The active restoration of land involves the conversion of the land from craters, caused by previous limestone quarrying at the location of the landfill, to a more natural landscape. The results show that the examined land use LCIA models award restoration of land to varying extents. These differences can mainly be explained by the fact that different models address different environmental issues associated with land use. In more recently developed models, however, positive land transformation (active restoration of land) is considered more frequently compared to older ones. It is problematic that many of the examined LCIA models have similar names when presented for the LCA practitioner, when they in fact address different damage pathways and areas of protection. Most of the examined LCIA models do not address active land restoration, and they fail to address the rapid decrease in untouched nature, which is an important environmental challenge related to land use. This study shows that it is possible to utilise existing impact assessment models to address active land restoration, and that land use related LCIA models can be employed as decision support for alternative locations. The current models do, however, have some shortcomings, and more research and method development are required with regard to land classification, intensities and management practices, to address intervention in untouched nature and transformation of land from one man-made situation to another. To avoid misunderstandings among LCA practitioners and increase the quality of results, land use related models in LCIA should be more transparent in identifying which environmental problems they address, and the units used ought to be relatable and easily interpreted. If possible, one should aim for a diverse use of environmental indicators and LCIA models in LCA. For future studies, when land use models are in focus, the authors recommend using the LANCA Land use model in combination with the Land competition model in CML-IA non-baseline and one of the models Land use biodiversity (Chaudhary et al., 2015), Land stress in LC-IMPACT or the sum of Land transformation, biodiversity and Land occupation, biodiversity in IMPACT World + Endpoint.