Floridi Andrea, Anda-León María Daniela, Kozakiewicz Tomasz, Bhattacharyya Megha, Thota Anilkrishna, Burt Peter, Tasciotti Luca, Selby Jan, Premji Zahra, Shisler Shannon
International Initiative for Impact Evaluation (3ie) London UK.
International Institute of Social Studies Erasmus University of Rotterdam Rotterdam the Netherlands.
Campbell Syst Rev. 2025 Apr 17;21(2):e70038. doi: 10.1002/cl2.70038. eCollection 2025 Jun.
Climate drivers such as the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) can impact multiple sectors globally. We are currently witnessing the effects of these teleconnections against the backdrop of a changing climate. This systematic review takes stock of the available evidence on compounding and cascading effects of El Niño and the Positive IOD on health, economic, migration, conflicts, and nutrition outcomes in low- and middle-income countries from the Indo-Pacific region. The review sheds light on how effects vary between and within the considered countries and explores potential sources of heterogeneity. The search of studies was carried out in January 2024 in 12 major databases/search engines and 14 institutional websites, using English keywords, and paired by forward and backward citation tracking of the included studies. The review's inclusion criteria encompassed quantitative studies as long as they provide an estimate of relationship between the climate driver and outcome, and qualitative studies that aim to infer causation such as realist evaluation or process tracing. The analysis used a combination of meta-analysis with random-effects models, median effects from correlational and regression studies, and narrative synthesis. We found that El Niño is likely to decrease agricultural production and productivity at the Indo-Pacific level, although the analysed studies are highly diverse. The absence of evidence on the effects of the considered climate drivers on migration, conflict, food security and nutrition is an important evidence gap. We found limited evidence on the differential effects by El Niño's and +IOD's magnitude and no studies examining their combined impact or qualitative effectiveness studies. The high risk of bias detected across studies calls for more thorough attention to study design, conduct, and reporting in answering questions about effects. Despite remaining evidence gaps, this review highlights potential effects of El Niño and +IOD in the Indo-Pacific and underscores the need for context-specific policy responses to mitigate risks at local and regional levels. Caution is warranted in interpreting the overall findings given the generally high risk of bias of evidence.
诸如厄尔尼诺-南方涛动（ENSO）和印度洋偶极子（IOD）等气候驱动因素会对全球多个领域产生影响。在气候变化的背景下，我们目前正在见证这些遥相关的影响。本系统综述评估了关于厄尔尼诺和正IOD对印度-太平洋地区低收入和中等收入国家的健康、经济、移民、冲突及营养结果的复合和级联效应的现有证据。该综述揭示了在所考虑的国家之间及国家内部影响是如何不同的，并探索了潜在的异质性来源。2024年1月，在12个主要数据库/搜索引擎和14个机构网站中使用英文关键词进行了研究检索，并通过对纳入研究的前后向引文追踪进行配对。该综述的纳入标准包括只要能提供气候驱动因素与结果之间关系估计的定量研究，以及旨在推断因果关系的定性研究，如实证评价或过程追踪。分析采用了随机效应模型的荟萃分析、相关和回归研究的中位数效应以及叙述性综合相结合的方法。我们发现，尽管所分析的研究差异很大，但在印度-太平洋地区，厄尔尼诺可能会降低农业产量和生产率。在所考虑的气候驱动因素对移民、冲突、粮食安全和营养的影响方面缺乏证据，这是一个重要的证据空白。我们发现关于厄尔尼诺和正IOD强度的差异影响的证据有限，且没有研究考察它们的综合影响或定性有效性研究。各项研究中检测到的高偏倚风险要求在回答有关影响的问题时，更全面地关注研究设计、实施和报告。尽管仍存在证据空白，但本综述突出了厄尔尼诺和正IOD在印度-太平洋地区的潜在影响，并强调需要针对具体情况制定政策应对措施，以减轻地方和区域层面的风险。鉴于证据的总体高偏倚风险，在解释总体研究结果时应谨慎。
