Nature-based solutions (NbS)

“A project is not nature-based because it contains nature. It qualifies only when nature is part of the solution and people and biodiversity both benefit. ”

Nature-based solutions have become prominent because they appear to answer several crises at once. Mangroves can reduce coastal risk while supporting fisheries and biodiversity. Urban trees can lower heat and improve public space. Restored wetlands can retain water, store carbon and create habitat. The promise is real, but the phrase has expanded faster than the discipline needed to protect it.

In 2022, the United Nations Environment Assembly agreed a multilateral definition. Nature-based solutions are actions to protect, conserve, restore, sustainably use and manage natural or modified ecosystems that address social, economic and environmental challenges effectively and adaptively while simultaneously providing human wellbeing, ecosystem services, resilience and biodiversity benefits.

Every part of that definition does work. There must be a defined societal challenge.

The action must use ecosystem protection, management or restoration as part of the response. It must be effective and adaptive. It must provide benefits for people and biodiversity, not one at the expense of the other. Mangrove restoration in Vietnam illustrates both the promise and the safeguards required.

Programmes supported by the Vietnam Red Cross and public authorities restored coastal mangroves in areas exposed to storms and erosion. Evidence and operational experience show that mangroves can reduce wave energy, protect dykes, support biodiversity and provide local products.

Other research from Vietnam has documented conflict where restoration restricted access to coastal resources or failed to provide local users with meaningful rights. A project can improve a protective ecosystem function while imposing livelihood costs on people who depend on the same coast.

That is not a minor implementation detail. Social legitimacy and governance are part of whether the solution works. Nature-based solutions are not synonymous with restoration. Protecting an intact forest, managing a watershed, changing grazing or creating urban green space may qualify. Nor are they necessarily alternatives to engineered infrastructure.

A hybrid design combining mangroves, warning systems and well-placed coastal defences may be more reliable than insisting that one approach replace the other. The label should not be used for any tree planting or carbon offset. A monoculture plantation that stores carbon while reducing biodiversity or displacing land users fails key elements of the definition.

An offset that allows continued fossil-fuel emissions is not a substitute for rapid emissions reduction.

Seddon and colleagues have emphasised that nature-based solutions must support, not delay, the protection of intact ecosystems and the phase-down of greenhouse-gas emissions. Evidence must match the hazard and context. A wetland may reduce moderate flood peaks but be overwhelmed by an extreme event. Urban trees cool streets only when canopy, water, species and spatial distribution are adequate.

Mangrove protection depends on coastal geomorphology, sediment and future sea-level conditions. Nature is dynamic, so design assumptions must be monitored and adapted. Scale and time create further challenges. Ecosystems may take years to establish, while communities need protection now. Benefits may occur downstream or beyond the project boundary.

Climate change can alter the future suitability of the ecosystem itself.

A robust solution plans for transition rather than assuming today’s habitat will remain stable. Rights and participation are essential safeguards. Land used for nature-based solutions may already support food, grazing, culture or customary tenure. Free, prior and informed consent applies where relevant to Indigenous Peoples, and meaningful participation is necessary more broadly.

The people expected to maintain the ecosystem should have a fair role in design, governance and benefit. A credible nature-based solution therefore states the challenge, compares alternatives, protects biodiversity, establishes rights, identifies trade-offs and measures both social and ecological performance. The phrase should signal a higher standard of design, not a greener vocabulary for an ordinary project.

Practical application

Define the societal challenge and the performance required before choosing the ecosystem action. Compare nature-based, engineered and hybrid options under realistic climate scenarios. Establish ecological baselines, rights, governance and safeguards with affected people. Monitor hazard reduction, ecosystem condition, biodiversity, distribution of benefits and unintended costs.

Include triggers for adaptation if the ecosystem or climate response differs from the design assumption.

Why it matters

Well-designed nature-based solutions can address climate risk, water, health and livelihoods while strengthening biodiversity and ecosystem resilience. They can create benefits that single-purpose infrastructure often misses, provided their limits and social conditions are recognised.

Common misconception

Nature-based solutions are often treated as tree planting, restoration or offsets under a new name. The agreed definition requires a societal challenge, demonstrable effectiveness and simultaneous benefits for people and biodiversity. Nature in the project is not enough.

Connections

Ecosystem services describe the flows a solution may mobilise. Ecosystem restoration is one possible action within the wider nature-based-solutions family. Climate resilience defines a common objective, while natural capital offers a stock-and-flow lens for assessing dependencies and change.

A question worth asking

Would your project still qualify as a nature-based solution if its biodiversity effects, land rights and distribution of costs were assessed as rigorously as its carbon or risk-reduction claim?

Selected references

United Nations Environment Assembly. 2022. Resolution 5/5: Nature-Based Solutions for Supporting Sustainable Development. IUCN. 2020. Global Standard for Nature-Based Solutions. Seddon, N. et al. 2021. Getting the Message Right on Nature-Based Solutions to Climate Change. Global Change Biology 27: 1518-1546. Chausson, A. et al. 2020. Mapping the Effectiveness of Nature-Based Solutions for Climate Change Adaptation.

Global Change Biology 26: 6134-6155. Powell, N. et al. 2011. Mangrove Restoration and Rehabilitation for Climate Change Adaptation in Vietnam. World Resources Report Case Study.