Effects of El Niño and the positive Indian Ocean Dipole (+IOD) on health, food security, economics and conflicts in low- and middle-income countries in the Indo-Pacific: A systematic review brief
How climate shocks such as El Niño affect agriculture, health, and economies in the Indo-Pacific, highlighting major evidence gaps and research needs.
This brief synthesises evidence on how major climate drivers affect health, agriculture, and economic outcomes in Indo-Pacific countries, highlighting knowledge gaps and implications for policy and research.
About this publication
| Authors | Andrea Floridi, María Daniela Anda León, Tomasz Kozakiewicz, Megha Bhattacharyya, Anilkrishna Thota, Peter Burt, Jan Selby, Luca Tasciotti and Shannon Shisler |
| Publication date | May 2025 |
| Publication type | Systematic review brief |
| Programme / grant | CGRTD Research Commissioning Centre (RCC), co-led by 3ie and University of Birmingham |
| Funding | Foreign, Commonwealth & Development Office (FCDO) (UK Government) |
| Licence | Unless otherwise stated, content on this page is licensed under a Creative Commons Attribution 4.0 International Licence (CC BY 4.0). |
Abstract
This systematic review examines how climate drivers, specifically El Niño and the positive Indian Ocean Dipole (+IOD), affect socioeconomic outcomes in low- and middle-income countries (L&MICs) in the Indo-Pacific region. The study synthesises evidence from 89 quantitative studies to assess impacts across key domains, including agriculture, health, economic outcomes, food security, migration, and conflict.
The findings indicate that El Niño events are associated with reduced agricultural production and productivity, although impacts vary by geography, crop type, and context. Evidence on health and economic outcomes is mixed, with no consistent effects identified for vector-borne diseases or prices at the regional level. Evidence on +IOD and several key outcomes, including migration, conflict, and food security, is limited or absent.
The review highlights substantial gaps in both the quantity and quality of available evidence, including a high risk of bias across studies and limited geographic coverage. It underscores the need for improved data, stronger methodologies, and more comprehensive research to inform policy responses to climate variability and its cascading impacts on vulnerable populations in the Indo-Pacific.
Key findings
- El Niño is likely to reduce agricultural production and productivity, though effects vary widely across countries, crops, and contexts.
- Evidence on health and economic impacts is mixed, with no consistent regional effects identified for diseases or prices.
- There is limited or no evidence on the impacts of +IOD, migration, conflict, food security, and nutrition, highlighting major research gaps.
Key recommendations
- Expand research to address major evidence gaps, particularly on +IOD, migration, conflict, and food security outcomes.
- Strengthen methodological quality by accounting for confounding factors, temporal dynamics, and climate variability.
- Improve data availability and coverage across underrepresented countries and outcomes to better inform policy responses.
Access this publication
Citation
Floridi, A. et al. (2025) Effects of El Niño and the positive Indian Ocean Dipole (+IOD) on health, food security, economics and conflicts in low- and middle-income countries in the Indo-Pacific: A systematic review brief. GRTD Research Commissioning Centre.
Related publications and outputs
- Effects of El Niño and the Positive Indian Ocean Dipole (+IOD) on Health, Food Security, Economics, and Conflict in Low- and Middle-Income Countries in the Indo-Pacific: A Systematic Review
- Protocol: Effects of El Niño and positive Indian Ocean Dipole on health, food security, migration, economics, and conflicts in the Indo-Pacific: A systematic review
References
References are provided extensively within the full systematic review.
Supporting sources include peer-reviewed quantitative studies, climate research, and analytical literature on socioeconomic outcomes related to El Niño and +IOD in the Indo-Pacific region.
Open Access Statement
This research output is made available in accordance with the FCDO Open Access Policy (December 2025). As part of a programme within the scope of this policy, this publication is freely accessible to all users without financial, legal, or technical barriers.
The full text is provided under a Creative Commons Attribution 4.0 International Licence (CC BY 4.0), which permits use, distribution, and adaptation of the material in any medium, provided appropriate credit is given to the original authors and source.
This output has been made available through an approved open access route and deposited in a recognised repository in line with FCDO requirements, including compliance with any required timelines for open access publication.
Where third-party material is included, users should check the relevant rights statements before reuse.
Accessibility
Please contact rcc@3ieimpact.org if you require an accessible version of the full PDF.
Questions
For questions about this publication, email rcc@3ieimpact.org with ‘El Nino Systematic Review Brief’ in the subject line.