Time-Series Study of Associations between Rates of People Affected by Disasters and the El Niño Southern Oscillation (ENSO) Cycle.

Holly Ching Yu Lam,Shakoor Hajat,Glenn Mcgregor,Emily Ying Yang Chan,Andy Haines

doi:10.3390/ijerph16173146

Abstract

The El Niño Southern Oscillation (ENSO) is a major driver of climatic variability that can have far reaching consequences for public health globally. We explored whether global, regional and country-level rates of people affected by natural disasters (PAD) are linked to ENSO. Annual numbers of PAD between 1964–2017 recorded on the EM-DAT disaster database were combined with UN population data to create PAD rates. Time-series regression was used to assess de-trended associations between PAD and 2 ENSO indices: Oceanic Niño Index (ONI) and multivariate El Niño Index (MEI). Over 95% of PAD were caused by floods, droughts or storms, with over 75% of people affected by these three disasters residing in Asia. Globally, drought-related PAD rate increased sharply in El Niño years (versus neutral years). Flood events were the disaster type most strongly associated with El Niño regionally: in South Asia, flood-related PAD increased by 40.5% (95% CI 19.3% to 65.6%) for each boundary point increase in ONI (p = 0.002). India was found to be the country with the largest increase in flood-related PAD rates following an El Niño event, with the Philippines experiencing the largest increase following La Niña. Multivariate ENSO Index (MEI)-analyses showed consistent results. These findings can be used to inform disaster preparedness strategies.

Highlights

The El Niño Southern Oscillation (ENSO) is a major driver of climatic variability that can have far reaching impacts across the globe
Implies that such disasters are unavoidable, we acknowledge that the occurrence and impact of such events may depend on various social and other vulnerability factors; we use the term here to distinguish them from technological disasters which are recorded on EM-DAT
This study suggests that ENSO plays a role, via climate related hazards, in determining health burdens—assuming that these are related to the number of people affected by disasters

Summary

Introduction

The El Niño Southern Oscillation (ENSO) is a major driver of climatic variability that can have far reaching impacts across the globe. The ocean warm phase of the cycle, termed El Niño, means ‘little boy’ in Spanish and refers to the Christ child since its appearance was historically detected around December time Both El Niño and the opposing ocean cool phase, La Niña (‘the little girl’), can significantly influence global climate patterns. El Niño and La Niña affects sea surface temperatures (SSTs) along the equatorial region of the Pacific Basin, which disrupts tropical atmospheric and ocean circulation patterns and modifies the mid-latitude jet stream [1]. This results in a range of environmental impacts in tropical and extra-tropical regions with altered temperature [2,3], precipitation patterns and extremes [4].

Methods

Results

Discussion

Conclusion