Research reveals hidden carbon emissions in urban parks: landscape life cycle assessment paves the way for low-carbon parks

With Finland’s new Building Act, life cycle assessment (LCA) of new buildings has become mandatory. While LCA is widely applied in the construction sector, life cycle climate impacts of urban green spaces, such as parks, remain largely unknown.

A recent study by researchers from Aalto University, Caroline Moinel, Matti Kuittinen and Ranja Hautamäki explores the applicability of LCA to urban green spaces. The researchers examined five urban parks in different settings across Helsinki to assess their carbon footprints.

The study reveals that while the case study urban parks have carbon dioxide uptake potential, emissions from the manufacture of products necessary for the construction of the parks can be significant. This indicates that carbon emissions are heavily influenced by design choices, functional needs, and city planning guidelines.

Low-carbon solutions can be promoted already in the planning phase

The study shows that carbon emissions from urban parks could be reduced already in the planning phase in several ways. Low-carbon parks would be promoted, for example, by preserving existing carbon stocks in vegetation and soils, utilising existing natural elements in new green spaces, finding low-emission alternatives to peat-based growing media, and reusing local materials and infrastructure whenever possible.

Additionally, adopting low-maintenance landscaping practices can further reduce emissions. According to the researchers, rethinking the concept of highly maintained urban green spaces and incorporating vegetation types that mimic natural ecosystems could enhance both carbon efficiency and biodiversity of urban green infrastructure.

’The role of urban green spaces requires further investigation to get a holistic understanding of carbon flows in the built environment,’ lead author of the study, doctoral researcher Caroline Moinel emphasizes.

The study also highlights the need for new assessment methods and data of urban green spaces as the availability of existing methods and data varies greatly between the life cycle stages and park components. Further research is particularly needed regarding the life cycle impacts of nursery production, construction, maintenance, and the end-of-life phase for vegetation, soils, and mulches. Additionally, there is little available data about emissions from playground equipment and street furniture.

Life cycle assessment is constantly developing with research. It will be a requirement for buildings from the beginning of 2026 and therefore a suitable method for the assessment of urban parks is needed. However, incorporating living organisms into the LCA framework represents a methodological shift that requires further refinement.

The study is part of the CO-CARBON research project, a multidisciplinary initiative funded by the Strategic Research Council. The project aims to measure and model the carbon sequestration capacity of urban greening while developing best practices for the design, implementation, and maintenance of carbon-wise urban greening. More information about the research project here.