Nature-Based Solutions and Climate Change – Four Shades of Green

'Nature-based -solutions' (NbS) aim to use nature in tackling challenges such as climate change, food security, water resources, or disaster risk management. The concept has been adopted by the European Commission in its research programme Horizon 2020 to promote its uptake in urban areas and establish Europe as a world leader of NbS. However, the concept has been defined vaguely. Moreover, its relationships with already existing concepts and approaches to enhance nature and its benefits in urban areas require clarification.Notably, ecosystem-based adaptation (EbA), urban green infrastructure (UGI) and ecosystem services (ESS) have gained prominence in academic debates and are increasingly referred to in policy-making. In this chapter main features of each of the concepts, as well as overlaps and differences between them are analysed based on a review of key literature.NbS is the most recent and broadest of the four concepts. Therefore, it may be considered as an umbrella to the other concepts but with a distinct focus on deployment of actions on the ground. EbA is a subset of NbS that is specifically concerned with climate change adaptation via the use of nature. As a planning approach, UGI, on the other hand, can provide strategic guidance for the integration of NbS into developing multifunctional green space networks at various scales. Finally, ESS value the benefits that humans derive from urban nature. ESS can support policy making for prioritising strategies and actions to maximise the benefits of NbS and can thus be considered as a kind of connecting concept between the other concepts. Overall, it is concluded that NbS is a powerful metaphor which, however, critically depends on UGI and ESS for its further definition and systematic uptake in urban areas.