Carbon Sequestration in Urban Green Spaces

Urban green spaces, including street trees, parks, gardens and green roofs, play a growing role in sequestering atmospheric carbon dioxide within city environments. Vegetation in these settings retains carbon in above-ground biomass and soils, creating a living sink that offsets urban emissions. Practices such as species selection, planting density and maintenance influence the accumulation of carbon, while innovative mapping and modelling techniques have refined our understanding of spatial patterns and sequestration rates. Globally, urban forests can sequester tens of millions of tonnes of CO2 per year, with local contributions varying according to climate, soil, vegetation structure and land-use history. Integrating green infrastructure into urban planning can amplify carbon storage and deliver co-benefits for biodiversity, heat mitigation and human well-being.

Research from Nature Portfolio

High-resolution remote sensing and LiDAR methods have been deployed to produce city-wide maps of tree biomass, revealing that structural metrics such as canopy height and leaf area index can explain more than 70 per cent of carbon stock variability across diverse urban settings. Subsequent field-based studies have quantified soil organic carbon accumulation beneath parks and green roofs, showing that established grass and shrub communities can store up to 25 kg C m−2 over a decade under optimal management. Modelling work has projected that, by strategically expanding tree cover and optimising species mixes for different climatic zones, urban forests could offset up to 20–30 per cent of current municipal CO2 emissions by mid-century.

Carbon Sequestration in Urban Green Spaces publication trend

The graph below shows the total number of articles in carbon sequestration in urban green spaces across all publications each year (not limited to Nature Index journals).

Technical terms

Carbon sequestration: The process of capturing and storing atmospheric CO2 in vegetation and soils.

Allometric equation: A mathematical relationship used to estimate tree biomass from measurements such as diameter at breast height and height.

Soil organic carbon (SOC): Carbon stored within soil organic matter, critical for long-term sequestration.

Remote sensing: The use of satellite or aerial data to assess vegetation structure and estimate biomass over large areas.

Leaf area index (LAI): The one-sided leaf surface area per unit ground area, indicative of photosynthetic capacity and carbon uptake.

References

1. Engaging Young People in the Development of Innovative Nature-Inspired Technologies for Carbon Sequestration in Cities: Case Studies from Portugal. Smart Cities (2024).
2. Tree Productivity Enhanced with Conversion from Forest to Urban Land Covers. PLOS ONE (2015).
3. Carbon Storage and Sequestration of Urban Street Trees in Beijing, China. Frontiers in Ecology and Evolution (2016).
4. Global urban reforestation can be an important natural climate solution. Environmental Research Letters (2021).