Nature-based solutions (NbS) are an approach that involves creating, protecting, restoring and managing ecosystems, and working alongside nature to benefit both humans and biodiversity. This article introduces the concept and origins of NbS, its recent popularity as a tool against the climate crisis, and its benefits and challenges.
What are nature-based solutions (NbS)?
NbS is an umbrella term with more than 20 definitions – each emphasising different aspects – to describe relying on natural systems and processes to tackle societal issues such as the UN Sustainable Development Goals [1, 2, 3]. NbS are guided by the principle that healthy ecosystems provide benefits and services to humans, like increasing food security, reducing greenhouse gas emissions or increasing carbon storage [4, 5]. NbS appreciates that the dual climate and biodiversity crises share common drivers. By recognising the value of nature and ecosystem services, we can help solve societal issues like natural disaster risk reduction and resource security while addressing biodiversity loss and climate change [2, 6, 7].
What counts as a NbS?
Unlike conservation, which is primarily about protecting biodiversity and often involves creating protected areas, NbS encompasses a spectrum of approaches including ecosystem conservation, ecosystem restoration, and improving land management practices to tackle social issues [4, 5, 6]. For example, restoring ecosystems such as coral reefs protects local communities against storms and floods. In some cases, this can be more effective than human-built protective infrastructure for the same purpose [4, 8]. Another example of NbS is creating green cities using porous infrastructure like green roofs and urban planting to absorb stormwater, keep cities cool, and promote urban wellbeing [4].
NbS in international policy discourse
The role of NbS in the climate and biodiversity crises has increased significantly in recent years with international bodies like the IPCC and IPBES recognising the importance of NbS [2]. In 2022, the potential of NbS in climate action was highlighted in the Sharm el-Sheikh Implementation plan as part of UNFCCC COP27. NbS was also included in the Kunming-Montreal Global Biodiversity Framework from the CBD (Convention on Biological Diversity) COP15 and COP14 for the RAMSAR Convention on Wetlands [9, 10, 11, 12, 13].
The comparative advantages and disadvantages of NbS
Research shows that NbS could provide 37% of the emission reductions necessary to ensure global temperature increases remain under two degrees Celsius by 2030, as per the Paris Agreement [2, 14].
NbS can potentially address climate mitigation and adaptation challenges at a comparatively low cost compared to human engineering while also creating additional benefits for nature and society [6]. Engineered options such as carbon dioxide capture and storage (CCS) or bioenergy technologies are often energy-intensive, expensive processes that don’t bring additional benefits like NbS [6].
However, it is difficult to measure the effectiveness of individual NbS projects, because the variation in definitions and case-specificity of many projects labelled under the NbS title leads to uncertainty about how to define their success and value. This can potentially lead to maladaptation [6]. Another important concern is the potential for NbS-branded projects to be used as greenwashing by major companies, which may exaggerate the impact of their nature-based activities without accurately quantifying the true impacts [2]. For example, reforestation projects may plant new trees without taking into account the impact on native ecosystems [2]. Furthermore, the existence of NbS must not become a scapegoat or distraction from necessary steps to decarbonise and reduce GHG emissions [5].
There also remain other challenges to implementing NbS, such as institutional norms slowing uptake, and a lack of funding for NbS projects. In 2019 less than 1% of climate finance was used for coastal protection, infrastructure, and disaster risk management projects that included NbS [6, 15].
Conclusion
Nature-based Solutions are a potentially powerful approach to addressing the dual climate and biodiversity crises, using nature to create environmental benefits while solving pressing societal issues. This has been reflected in a dramatic increase in the popularity of NbS in recent years in international climate discourse. NbS are a strong tool for climate action, however, their effectiveness is context-dependent and shouldn’t distract from the need to decarbonise existing infrastructure and reduce GHG emissions.
