Overview

Urban Challenges

Urban areas contribute more than 60% of global greenhouse gas (GHG) emissions, through residential, commercial, and transportation activities. Nature-based solutions (NbS) are increasingly being adopted by cities worldwide to enhance carbon sequestration, offsets emissions, and promotes sustainable land management practices, thus contributing to global climate change mitigation efforts.

Nature-based Solutions

Realistic NbS implementation plans toward carbon neutrality, such as restoring natural ecosystems and increasing urban green resources, need to be both effective in mitigating carbon emissions at the global level and suitable for the socio-economic and physical conditions at the local level. Prioritizing suitable sites and solutions can enhance the long-term viability of NbS. In our research,we have explored a systematic approach to spatially prioritizing different types of NbS implementations in multiple major EU cities.

Types of Nature-based Solutions

Motivation

The motivation for developing this tool is to offer the necessary flexibility for NbS planning, by enabling users to interact and iterate through our spatial allocation processes. Successful adoption of NbS and realization of their functionality requires a holistic and collaborative planning approach that incorporates stakeholders across scales and disciplines. This platform aims to serve as a point of departure to facilitate the identifying suitable interventions and enhancing the awareness of NbS opportunities in urban settings.

Potential pathways of NbS to reduce emissions

NbS Spatial Allocation

We selected five types of NbS (green infrastructure (GI), street trees & green pavements, urban green spaces & agriculture, habitat preservation & remediation, and green buildings) as our study objectives. From established definitions of NbS in the literature, we identified the level of benefit of different types of NbS at different urban settings and synthesized quantitative indicators to describe the impact of NbS on sectoral carbon emissions.

Comparative summary of NbS impacts to sectoral emissions

The NbS implementations were spatially allocated based on three major factors: the sectoral carbon emission, potential NbS benefits, and the local context of each location. For example, street trees & green pavements as an NbS to promote walking and cycling should ideally be located along city roads in high-density urban areas, while preserved habitats should be located at the urban fringe where new urban developments are likely to occur. We have developed practical principles and criteria that systematically guide the spatial allocations of each type of NbS.

Typology: Click here!
Infrastructure Criteria
Street trees High transport emissions AND High population density
Green buildings (High residential emission OR High industry emission) AND Building rooftops
Green infrastructure (High residential emissions OR High industrial emissions) AND Available land cover* AND (NOT existing preserved areas)
Urban green areas (High population density OR High built-up areas) AND Available land cover**
Greenbelts Low population density AND Existing preserved areas
Key variables and data sources used in the analysis
Type Description Data Source Year Available
Emissions CO2 emissions by sector Global Carbon Grid 2019 Click here!
Residential development Urban fabric density Urban Atlas via Copernicus 2018 Click here!
Population Population per cell Global Carbon Grid 2019 Click here!
Building density Urban fabric density classifications Urban Atlas via Copernicus 2018 Click here!
Transportation Roadway network with classification and speed OpenStreet Map 2017 Click here!
Industry Industrial, commercial, public, military and private units Urban Atlas via Copernicus 2018 Click here!
City boundaries Functional urban area boundaries European Commission 2015 Click here!