People type what are nature-based solutions and get a wetland, a forest, a city park. IUCN's definition does not start with a place. It starts with a verb.
Nature-based solutions, often shortened to NbS, are, in IUCN's own 2016 words, "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."
That is the definition this page is about. Not a habitat type. Not a procurement nickname. Not a certificate. An action, aimed at a living system, for a societal problem — with both people and biodiversity required to benefit at the same time.
what the definition is actually saying
IUCN's sentence does four jobs. Miss one and you no longer have what the Union defined.
An action. Protect. Sustainably manage. Restore. Those are verbs. They describe work someone decides to do. A wetland is not a verb. A canopy is not a verb. The living system was already there.
An object. Natural or modified ecosystems. The action is about something living — intact, degraded, or designed. The object is not the action.
A societal challenge. Food, water, climate, health, disaster risk, development. IUCN is explicit: NbS are designed to address major societal challenges. A restoration that does not aim at one of those is still restoration. It is not, by this definition, an NbS.
Two outcomes, together. Human well-being and biodiversity benefits. Simultaneously. A gray project that happens to mention trees is not this. A biodiversity project that ignores people is not this either. The standard exists because the phrase was already being stretched.
You might be thinking this is a semantic fight. It is not. If a city, a utility, or a corporate sustainability office funds the name of the project, they can close the grant, cut the ribbon, and still lose the living system the project was about. The verb ended. The wetland did not get a payroll.
four things that get filed under one heading
The mix-up is structural. Four different objects share a hallway, and people point at whichever is nearest.
| what it is | what it is not | |
|---|---|---|
| action | protect, manage, or restore a living system to address a societal challenge — the NbS | the wetland, the canopy, the reef |
| living system | the named ecosystem the action is about | a project label, a standard, a ribbon |
| standard | a process that qualifies whether an action counts as NbS | a payor, a funded acre |
| certificate | a funding instrument tied to a named living condition | the action, or the system |
An engineer should hear this as a scope distinction, not poetry. The action is the work package. The living system is the asset whose condition determines whether the work package holds. The standard is quality assurance on the work package. The certificate is how someone can fund the condition after the work package closes.
A practitioner who has spent years applying the IUCN Global Standard should not hear that the standard is fake. It is a real process. It is also not a treasury. Qualifying an action is not the same as paying for the living system the action depends on.
A conservationist should not hear that a wetland is a project. The wetland exists whether or not anyone files an NbS self-assessment. Labeling the restoration does not create the marsh.
the trap is treating the label as the system
Three substitutions show up in almost every NbS conversation.
The project name becomes the place. A "coastal NbS" on a slide. A "watershed NbS" in a grant. Useful shorthand until the budget treats the shorthand as the thing. Then the capital line funds design and construction, the operating line never arrives, and the living system is left holding a completed project.
The standard becomes the funding. IUCN's Global Standard — first edition 2020; second edition launched 10 October 2025 and published 2026 — is a quality-assurance tool: eight criteria, a self-assessment, a way to keep the phrase from meaning whatever the brochure needs it to mean. Meeting the criteria tells you the action was designed as NbS. It does not write a check for the canopy that action needs to keep working. A standard is not a funded acre is the next cut.
The ribbon becomes the end. Capex can close. The living system still has a condition. Who pays after the NbS ribbon is the last post in this series. This one only needs the distinction: a completed action is not a completed living system.
You might already be objecting that plenty of NbS projects include maintenance. Some do. The ones that do have named a second ticket — care, monitoring, adaptive management — and funded it. The ones that don't have treated the action as if it were the object. That is the error this definition is for.
cousins, not clones
The phrase has relatives. Absorb them. Do not become them, and do not dunk on them.
The IUCN Global Standard for Nature-based Solutions is the process for designing, verifying, and scaling the action. Use it. That is the Union's job.
ISO 17620:2025 is a different process: how to design and implement biodiversity net gain on a development project. It is not an NbS standard, and it is not a payor. Law-made buyers of that kind live in demand by statute.
The U.S. Army Corps of Engineers wrote nature-based solutions into civil-works guidance in an April 2024 memo from the Assistant Secretary of the Army for Civil Works, with Engineering With Nature as the practice underneath. That is a procurement dialect for actions and features on a civil-works sheet. The living system is still the living system. The USACE object-name — natural infrastructure — has its own how-to; this series stays on the action label. How to implement natural infrastructure already owns that lane.
UNEP and the SEEA community keep ecosystem-service flow accounts so the work living systems already do can show up in national books. Accounting for flows is not funding the stock. It is a cousin of the definition, not a replacement for it.
Four names for overlapping rooms — nature-based, natural, green, living — are mapped in green, natural, living infrastructure. This post will not rewrite that dialect table. NbS is not natural infrastructure is the cut that stays on this series' spine.
the three posts that already own the head term
Nature-based solutions, as a search phrase, is already claimed on this site — three times. This page will not steal it.
- why nature-based solutions require proactive financing — the corporate and insurer case
- the city that treats its rivers like infrastructure — the municipal case
- the risks your grid hardening can't reach — the utility case
This post is the definition underneath those three. It does not retell them.
an nbs is not a natural asset
A natural asset is the named living system: this wetland, this canopy, this reef. You can point at it without a project document. What a natural asset actually is is the foundation-term companion.
An NbS is the action taken on that asset to address a societal challenge. You can restore a wetland as an NbS and still miss that the wetland is the thing. That cut — action versus object — is an nbs is not the asset.
The two phrases travel together because the action is useless if the object fails. They are still two objects. Confusing them is how a grant closes on "the NbS" while the marsh thins.
the second ticket is the living condition
The wetland, canopy, and reef exist whether or not anyone labels a project NbS. ensurance funds the living condition the project depends on — it is not the project name.
That is a narrow claim. Insurance pays after a defined loss. Ensurance is built to fund present condition before the loss, on a named place. A certificate is specific ensurance: a funded relationship with that living condition, not another name for the NbS. A coin funds protection more broadly across the protocol. Neither instrument is the action, and neither is the marsh.
Our stage, stated plainly. The instruments are live. The volumes are small. The recurring-payment side is still being manufactured. Cities and utilities that need a dedicated stream today already have tested paths — rates, fees, watershed programs — and nothing here requires waiting for us. The definition is right whether or not our instrument is the one that ends up carrying the second ticket.
If you came here to understand the phrase, you have it. The next useful read is the action-versus-object cut, or one of the three posts that already use the head term in the field.
frequently asked questions
what are nature-based solutions?
Nature-based solutions are 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. That is IUCN's 2016 definition. They are the action, not the living system the action is about.
what is nbs?
NbS is the abbreviation for nature-based solutions. Same definition: an action on a living system, aimed at a societal problem, required to benefit people and biodiversity together. It is not a habitat type, a standard, or a financial instrument.
how does iucn define nature-based solutions?
IUCN (Resolution 6.069, 2016) defines them 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." The IUCN Global Standard then supplies the process for designing and verifying that an action meets that definition.
how is an nbs different from a natural asset?
A natural asset is the named living system. An NbS is an action taken on that system to address a societal challenge. The wetland is the asset. Restoring it for a societal purpose can be the NbS. What a natural asset actually is holds the object; this series holds the action label.
the series
Five posts. One spine: NbS is an action. The living system is the object. The standard is a process. Funding the living condition is a second ticket.
- what nature-based solutions actually are — the definition (you are here)
- an nbs is not the asset — you can restore a wetland as an NbS and still miss the wetland
- an nbs standard is not a funded acre — IUCN's process is not a payor
- nbs is not natural infrastructure — one is an action label; the other is a procurement name for a living system already doing work
- who pays after the nbs ribbon — the project can close; the living system still has a payroll
Adjacent: green, natural, living infrastructure, what a natural asset actually is, demand by statute, and the three head-term owners linked above.