Life Cycle Assessment Applied to Nature-Based Solutions: Learnings, Methodological Challenges, and Perspectives from a Critical Analysis of the Literature

Abstract

The use of life cycle assessment (LCA) allows work to go beyond the traditional scope of urban nature-based solutions (NBS), in which ecosystem services are provided to citizens, to include environmental impacts generated over the entire life cycle of the NBS, i.e., from raw material extraction, through materials processing, production, distribution, and use stages, to end-of-life management. In this work, we explored how LCA has been applied in the context of NBS through a critical analysis of the literature. Systems under review were not restricted to one typology of NBS or another, but were meant to cover a broad range of NBS, from NBS on the ground, water-related NBS, building NBS, to NBS strategies. In total, 130 LCA studies of NBS were analysed according to several criteria derived from the LCA methodology or from specific challenges associated with NBS. Results show that studies were based on different scopes, resulting in the selection of different functional units and system boundaries. Accordingly, we propose an innovative approach based on the ecosystem services (ES) concept to classify and quantify these functional units. We also identify and discuss two recent and promising approaches to solve multifunctionality that could be adapted for LCA of NBS.

Seaweed: a sustainable solution for greening drug manufacturing in the pursuit of sustainable healthcare

“…The first step is to define the goal and scope of the study, which includes determining the purpose of the assessment, specifying the functional unit (such as the production of one unit of the drug), setting system boundaries, and identifying the relevant environmental impact categories to be considered (such as greenhouse gas emissions, water use, energy consumption) [200]. Next, an inventory analysis is conducted to identify and quantify all the resources and emissions associated with seaweed-based drug manufacturing.…”

Performance assessment of the ecosystem services provided by urban Nature-based solutions: focus on rainwater management

“…On one hand, ecosystem services are widely studied and modeled [62][63][64]. However, on the other hand, few studies investigate the negative impacts of NBS, and they primarily focus on disservices while overlooking environmental impacts as described by LCA methods [65].…”

“…The application of LCA methods to NBS is therefore an innovative way to compensate this lack of environmental assessment [65]. French decision aid tools using LCA analysis for buildings and districts environmental assessment use Life Cycle Inventories (LCI) for each building component that are compiled in the French database INIES [66].…”

Environmental Footprint Neutrality Using Methods and Tools for Natural Capital Accounting in Life Cycle Assessment

“…Many other examples exist in the NbS literature where the LCA method is used to derive metrics of negative impact, which are then compared with the positive scores from the ES generated by the NbS, in most cases in the form of carbon removal capacity [102]. In this regard, NbS can be considered the best available renaturation and restoration measures to implement in cities or across degraded landscapes to increase the supply of ES and provide balancing alternatives in the contexts of an ESA-LCA mitigation hierarchy [103].…”

“…This may be regarded as a "direct" intervention producing an insetting result, where the impact is neutralized in loco. While an organization from, e.g., the tertiary sector, which does not own any land, may invest in the implementation of restoration actions or NbS, which are sources of quantifiable ES [102]. In this case, priority for land restoration should be given following a proximity principle, that is investing preferentially on projects within the same or the closest possible region or urban setting.…”