Nature-based Solutions in Small Island Developing States Can Generate “Triple Wins" for Climate Adaptation, Biodiversity, and People

Small Island Developing States (SIDS) are among the countries most vulnerable to climate change, facing escalating risks from sea-level rise, storms, coastal erosion, ecosystem degradation, and threats to food and water security.

Nature-based solutions (NbS) are increasingly recognised as a key approach for climate adaptation because they can simultaneously reduce climate risks, support biodiversity, and strengthen livelihoods and local economies.

This positions NbS as a strategic approach for enabling synergistic progress across multiple international policy agendas, including the Paris

Agreement, the Kunming-Montreal Global Biodiversity Framework, the Sustainable Development Goals, and the Antigua and Barbuda Agenda for SIDS (ABAS).

This policy brief synthesises evidence from a systematic review of 49 studies reporting 53 NbS interventions across 26 SIDS. The underlying research draws on evidence from UN-defined SIDS, comprising 39 UN Member States and 18 Associate Members across the Caribbean, Pacific, Atlantic, Indian Ocean, and South China Sea regions. Most of these States are members of the Organisation of African, Caribbean and Pacific States (OACPS). As such, the findings presented in this brief are broadly applicable to OACPS SIDS while also drawing on lessons and experiences from the wider SIDS community.

Key Findings

› The majority of NbS interventions reported positive climate adaptation outcomes. However, many studies lacked robust evidence frameworks.

› NbS were reported to deliver “triple wins” for climate, biodiversity, and people, supporting livelihoods, food security, and local economies.

› Evidence is heavily concentrated in terrestrial systems, while coastal and marine NbS remain underrepresented despite growing coastal climate risks in SIDS.

› Formal economic appraisals and private sector involvement in NbS implementation were rare.

› Equity considerations, local ownership, and distributional impacts were often poorly reported.

› More than half of SIDS were absent from the peer-reviewed evidence base.

Policy Implications

› NbS offer a core implementation strategy for the ABAS framework by advancing climate adaptation, biodiversity conservation, and sustainable development objectives simultaneously in SIDS.

› Strengthening the evidence base through baselines, counterfactuals, and long-term monitoring is critical for informed adaptation planning and investment decisions.

› Coastal and marine NbS should be prioritized within research, monitoring, and assessment efforts given the high exposure of SIDS to coastal climate risks.

› Robust economic evaluation and appropriate private sector engagement are necessary for greater adaptation investment and implementation

› Equity, justice, and local leadership should be treated as core components of effective NbS implementation.

› Greater support for SIDS-led research and knowledge-sharing is needed to strengthen the representativeness, accessibility, and relevance of the NbS evidence base.