Nature-based solutions (or nature-based systems, abbreviated as NBS or NbS) describe the development and sustainable use of natural processes and biodiversity to address diverse socio-environmental issues. These issues include climate change mitigation, adaptation, and Climate restoration, human security issues such as water security and food security, and disaster risk reduction. The aim is that resilient ecosystems (whether natural, managed, or newly created) provide solutions for the benefit of both societies and biodiversity. The 2019 UN Climate Action Summit highlighted nature-based solutions as an effective method to combat climate change. For example, nature-based systems for climate change adaptation can include natural flood management, restoring natural coastal defences, and providing local cooling.
The concept of NBS is related to the concept of ecological engineering and ecosystem-based adaptation. NBS are also related, conceptually to the practice of ecological restoration. The sustainable management approach is a key aspect of NBS development and implementation.
Mangrove restoration efforts along coastlines provide an example of a nature-based solution that can achieve multiple goals. Mangroves moderate the impact of waves and wind on coastal settlements or cities, and they sequester carbon. They also provide nursery zones for marine life which is important for sustaining fisheries. Additionally, mangrove forests can help to control coastal erosion resulting from sea level rise.
Green roofs, blue roofs and green walls (as part of green infrastructure) are also nature-based solutions that can be implemented in urban areas. They can reduce the effects of urban heat islands, capture stormwater, abate pollution, and act as carbon sinks. At the same time, they can enhance local biodiversity.
NBS systems and solutions are forming an increasing part of national and international policies on climate change. They are included in climate change policy, infrastructure investment, and climate finance mechanisms. The European Commission has paid increasing attention to NBS since 2013. This is reflected in the majority of global NBS case studies reviewed by Debele et al (2023) being located in Europe. While there is much scope for scaling-up nature-based systems and solutions globally, they frequently encounter numerous challenges during planning and implementation.
The IPCC pointed out that the term is "the subject of ongoing debate, with concerns that it may lead to the misunderstanding that NbS on its own can provide a global solution to climate change". To clarify this point further, the IPCC also stated that "nature-based systems cannot be regarded as an alternative to, or a reason to delay, deep cuts in GHG emissions".
Definition
The International Union for Conservation of Nature (IUCN) defines NBS as "actions to protect, sustainably manage, and restore natural or modified ecosystems, that address societal challenges effectively and adaptively, simultaneously providing human well-being and biodiversity benefits". Societal challenges of relevance here include climate change, food security, disaster risk reduction, water security.
In other words: "Nature-based solutions are interventions that use the natural functions of healthy ecosystems to protect the environment but also provide numerous economic and social benefits."Dubash, N.K., C. Mitchell, E.L. Boasson, M.J. Borbor-Cordova, S. Fifita, E. Haites, M. Jaccard, F. Jotzo, S. Naidoo, P. Romero-Lankao, M. Shlapak, W. Shen, L. Wu, 2022: Chapter 13: National and sub-national policies and institutions. In IPCC, 2022: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [P.R. Shukla, J. Skea, R. Slade, A. Al Khourdajie, R. van Diemen, D. McCollum, M. Pathak, S. Some, P. Vyas, R. Fradera, M. Belkacemi, A. Hasija, G. Lisboa, S. Luz, J. Malley, (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA. doi: 10.1017/9781009157926.015 They are used both in the context of climate change mitigation as well as adaptation.Lecocq, F., H. Winkler, J.P. Daka, S. Fu, J.S. Gerber, S. Kartha, V. Krey, H. Lofgren, T. Masui, R. Mathur, J. Portugal-Pereira, B. K. Sovacool, M. V. Vilariño, N. Zhou, 2022: Chapter 4: Mitigation and development pathways in the near- to mid-term. In IPCC, 2022: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [P.R. Shukla, J. Skea, R. Slade, A. Al Khourdajie, R. van Diemen, D. McCollum, M. Pathak, S. Some, P. Vyas, R. Fradera, M. Belkacemi, A. Hasija, G. Lisboa, S. Luz, J. Malley, (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA. doi: 10.1017/9781009157926.006
The European Commission's definition of NBS states that these solutions 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". In 2020, the EC definition was updated to further emphasise that "Nature-based solutions must benefit biodiversity and support the delivery of a range of ecosystem services."
The IPCC Sixth Assessment Report pointed out that the term nature-based solutions is "widely but not universally used in the scientific literature". As of 2017, the term NBS was still regarded as "poorly defined and vague".
The term ecosystem-based adaptation (EbA) is a subset of nature-based solutions and "aims to maintain and increase the resilience and reduce the vulnerability of ecosystems and people in the face of the adverse effects of climate change".
History of the term The term nature-based solutions was put forward by practitioners in the late 2000s. At that time it was used by international organisations such as the International Union for Conservation of Nature and the World Bank in the context of finding new solutions to mitigate and adapt to climate change effects by working with natural ecosystems rather than relying purely on engineering interventions.
Many indigenous peoples have recognised the natural environment as playing an important role in human well-being as part of their traditional knowledge systems, but this idea did not enter into modern scientific literature until the 1970's with the concept of ecosystem services.
The IUCN referred to NBS in a position paper for the United Nations Framework Convention on Climate Change.IUCN (International Union for Conservation of Nature). 2009. No time to lose – make full use of nature-based solutions in the post-2012 climate change regime. Position paper on the Fifteenth session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (COP 15). Gland: IUCN. The term was also adopted by European policymakers, in particular by the European Commission, in a reportEuropean Commission. 2015. Towards an EU Research and Innovation policy agenda for nature-based solutions & re-naturing cities. Final Report of the Horizon2020 Expert Group on Nature-Based Solutions and Re-Naturing Cities. Brussels: European Commission. stressing that NBS can offer innovative means to create jobs and growth as part of a green economy. The term started to make appearances in the mainstream media around the time of the Global Climate Action Summit in California in September 2018.
Objectives and framing Nature-based solutions stress the sustainable use of nature in solving coupled environmental-social-economic challenges. NBS go beyond traditional biodiversity conservation and management principles by "re-focusing" the debate on humans and specifically integrating societal factors such as human well-being and poverty reduction, socio-economic development, and governance principles.
The general objective of NBS is clear, namely the sustainable management and use of Nature for tackling societal challenges.IUCN (International Union for Conservation of Nature). 2016. Resolution 077 World Conservation Congress 2016, Hawaiʻi (https://portals.iucn.org/congress/motion/077 ) 17. European Commission. 2016. Horizon2020 Work Programme 2016–2017 – 12. Climate action, environment, resource efficiency & raw materials, 99 pp. (http://ec.europa.eu/research/participants/data/ref/h2020/wp/2016_2017/main/h2020-wp1617-climate_en.pdf ) However, different stakeholders view NBS from a variety of perspectives. For instance, the IUCN puts the need for well-managed and restored ecosystems at the heart of NBS, with the overarching goal of "Supporting the achievement of society's development goals and safeguard human well-being in ways that reflect cultural and societal values and enhance the resilience of ecosystems, their capacity for renewal and the provision of services".
The European Commission underlines that NBS can transform environmental and societal challenges into innovation opportunities, by turning natural capital into a source for green growth and sustainable development. Within this viewpoint, nature-based solutions to societal challenges "bring more, and more diverse, nature and natural features and processes into cities, landscapes and seascapes, through locally adapted, resource-efficient and systemic interventions".European Commission. 2016. Horizon2020 Work Programme 2016–2017 – 12. Climate action, environment, resource efficiency & raw materials, 99 pp. ) As a result, NBS has been suggested as a means of implementing the nature-positive goal to halt and reverse nature loss by 2030, and achieve full nature recovery by 2050.
Categories The IUCN proposes to consider NBS as an umbrella concept. Categories and examples of NBS approaches according to the IUCN include: Category of NBS approachesExamplesEcosystem restoration approachesEcological restoration, ecological engineering, forest landscape restorationIssue-specific ecosystem-related approachesEcosystem-based adaptation, ecosystem-based mitigation, climate adaptation services, ecosystem-based disaster risk reductionInfrastructure-related approachesNatural infrastructure, green infrastructureEcosystem-based management approachesIntegrated coastal zone management, integrated water resources managementEcosystem protection approachesArea-based conservation approaches including protected area management
Types
Scientists have proposed a typology to characterise NBS along two gradients:
"How much engineering of biodiversity and ecosystems is involved in NBS", and "How many ecosystem services and stakeholder groups are targeted by a given NBS".
The typology highlights that NBS can involve very different actions on ecosystems (from protection, to management, or even the creation of new ecosystems) and is based on the assumption that the higher the number of services and stakeholder groups targeted, the lower the capacity to maximise the delivery of each service and simultaneously fulfil the specific needs of all stakeholder groups.
As such, three types of NBS are distinguished (hybrid solutions exist along this gradient both in space and time. For instance, at a landscape scale, mixing protected and managed areas could be required to fulfill multi-functionality and sustainability goals):
Type 1 – Minimal intervention in ecosystems