The European Commission defines Nature-based solutions (NbS) as:

"Solutions that are inspired and supported by nature, which are cost-effective, simultaneously provide environmental, social and economic benefits and help build resilience. Such solutions bring more, and more diverse, nature and natural features and processes into cities, landscapes and seascapes, through locally adapted, resource-efficient and systemic interventions". Nature-based solutions must therefore benefit biodiversity and support the delivery of a range of ecosystem services.

In early 2022, a definition for NbS was agreed at the United Nations Environment Assembly (UNEA): “Acknowledging the need for a multilaterally agreed definition of the concept of nature-based solutions, cognizant of and in harmony with the concept of ecosystem-based approaches, and in the light of concerns about the potential misuse of the concept of nature-based solutions”.

This multilaterally agreed definition builds on the European Commission's definition, and goes further, by recognizing the links between NbS and the Sustainable Development Goals and the three Rio conventions, to name a few.

UNEA resolution 5/5 defines nature-based solutions as “actions to protect, conserve, restore, sustainably use and manage natural or modified terrestrial, freshwater, coastal and marine ecosystems which address social, economic and environmental challenges effectively and adaptively, while simultaneously providing human well-being, ecosystem services, resilience and biodiversity benefits”. The definition goes further to highlight a number of criteria and considerations for the application of NbS, including social and environmental safeguards.

As interventions that promise to simultaneously address multiple goals and to provide a wide range of environmental, economic and social benefits, nature-based solutions offer significant promise as responses to sustainability challenges that resonate at a local level whilst also addressing global issues. They are also seen to have the potential to offer a transformative approach for meeting sustainability challenges, through delivering processes such that sustainable communities are designed, strategies formulated and initiatives implemented which are inclusive and where their outcomes are transformative not only in environmental terms but also account for issues of social justice.

Nature-based solutions can be a powerful tool for cities dealing with the contemporary sustainability challenges including degradation of natural capital and ecosystem services, vulnerability to climate change and natural disasters, as well as corresponding health and wellbeing issues. NbS have the potential to boost local economies and create business opportunities.

The EU Biodiversity Strategy for 2030 aims to secure healthy, resilient, biodiversity-rich ecosystems that deliver the range of services essential to the prosperity and well-being of citizens. Nature-based solutions - with healthy and biodiverse ecosystems at their core - are central to achieving the objectives of this strategy and sustainably tackling wider societal, economic and environmental challenges.