The air cooling indicator measures the lowering of air temperature by a nature-based solution. Cooling the air can be a climate action for adaptation to a warmer climate, as well as mitigate the negative effects of the urban heat island effect.

Describes the significance of arts in urban green spaces and their meaning for urban visitors.

How people relate to each other and the type of social interactions they share, e.g. playing, sports, music, art etc. Most definitions of community include a sense of belonging from rewarding experiences such as a positive mental state of acceptance and active participation in a community.

Carbon (C) storage is an indicator for the amount of carbon in water, soil and biomass. Carbon storage helps with the resilience and mitigation of climate change.

Evaluates the impact of a nature-based solution on noise annoyance attenuation.

Measures the impact on the number of recorded crimes (such as robberies), nearby or within a nature-based solution.

Assesses whether the implementation of a nature-based solution has a positive effect on citizens’ involvement in local green space management processes

Refers to the level of knowledge on ecological connections by users of nature-based solutions, decision-makers etc. 

A score on economic value of nature that reflects its value to the urban residents, relative to other types of urban nature types. It therefore provides a relative value of one type of urban nature relative to another, within an urban setting.

Describes how citizens’ engagement in the community, especially in the development of the city, can be fostered through nature-based solutions

Measures the effects of environmental educational activities related to water in students’ knowledge about nature-based solutions involving water bodies (rivers, lakes, ponds, wetlands and deltas) and biodiversity protection related to their ecosystems.

Assesses the spatial equality or inequality in the access to public green and blue spaces, and is related to the difference in access to these areas by people from different income and ethnic groups.

Assess the percentage of flowers which mature into fruits. Pollination contribute to a higher fruit set.  

Green area (ha) is used as a proxy for biodiversity. Biodiversity is defined as the variability among living organisms from all sources, but is mostly measured as species richness and is influenced by factors such as size of and habitat complexity. 

Evaluates the health effects of proximate urban green and blue spaces in certain neighbourhoods, residents or community.

Describes the benefits of historical and cultural aspects of nature-based solutions to citizens. The benefits cover aspects of artistic expressions such as graffiti, arts and murals, written, drawn or painted as forms of communication.

Assesses the number of jobs created as a result of the implementation of a nature-based solution. 

Is about the “circumstances” under which nature-based solutions are being implemented. In most cases, the legal conditions in a city play a role in the implementation of a nature-based solution. They can be either fostering or demanding nature-based solutions or they can be hindering or neutral.

Self-assessment of individuals of their quality of life and how they perceive the value of certain aspects of their life.

Assesses the efficiency (in %) of urban vegetation to remove pollutants (i.e. PM10 and PM2.5, particular matter particles smaller than 10 and 2.5 µm. resp.) from the air.

Peak flow reduction (in %) indicates how nature-based solutions reduce the peak flow during storms and/or flooding event. Knowing how much an intervention reduces the peak flow makes it possible to compare nature-based solution’s effectiveness to reduce flooding risks. 

Self-reported assessment of individuals about their general health status, covering both their physical and mental health.

Assesses the level of perceived public and community safety and citizens’ fear of crime and harassment in public green spaces (e.g. parks, urban forests). 

Physiologically equivalent temperature is a human biometeorological index that models how comfortable the climate is. It can be used to indicate a nature-based solution's effect to mitigate or adapt to climate change.

Assesses the abundance of pollinators such as honeybees and bumblebees within an urban setting. Pollinators play a critical role in contributing to the production of vegetables and fruits through pollination. 

Run-off reduction measures the relative change (%) in the total volume of surface water after the implementation of a nature-based solution and thus indicates how efficient a nature-based solution reduce surface water run-off during storms and/or flooding event. 

Wetland area indicates the possibility of coastal protection for storms and large waves. The relationship between wetland area and coastal protection cannot be directly measured and instead we have used the nonlinear relationship between wave attenuation and wetland size.