Climate has contrasting direct and indirect effects on armed conflicts

David Helman,Benjamin F Zaitchik,Chris Funk

doi:10.1088/1748-9326/aba97d

Abstract

There is an active debate regarding the influence that climate has on the risk of armed conflict, which stems from challenges in assembling unbiased datasets, competing hypotheses on the mechanisms of climate influence, and the difficulty of disentangling direct and indirect climate effects. We use gridded historical non-state conflict records, satellite data, and land surface models in a structural equation modeling approach to uncover the direct and indirect effects of climate on violent conflicts in Africa and the Middle East (ME). We show that climate–conflict linkages in these regions are more complex than previously suggested, with multiple mechanisms at work. Warm temperatures and low rainfall direct effects on conflict risk were stronger than indirect effects through food and water supplies. Warming increases the risk of violence in Africa but unexpectedly decreases this risk in the ME. Furthermore, at the country level, warming decreases the risk of violence in most West African countries. Overall, we find a non-linear response of conflict to warming across countries that depends on the local temperature conditions. We further show that magnitude and sign of the effects largely depend on the scale of analysis and geographical context. These results imply that extreme caution should be exerted when attempting to explain or project local climate–conflict relationships based on a single, generalized theory.

Highlights

There is a suggested linkage between violent conflict and climate, the underlying mechanisms of the link are still under debate[1,2]
This indirect influence is relevant to theories like the “engagement” hypothesis, which claims that when climate crisis reduces economic productivity people become more likely to engage in conflicts than in economic activities6,7, or the “inequality” hypothesis, which argues that conflict may upsurge when climate crisis increases economic inequality because of increasing efforts to redistribute assets8, and the “state weakness” hypothesis that suggests a weakening of governmental institutions and their ability to suppress violence due to decline in economic productivity following climate crisis 9
We focus on Africa and the Middle East [ME] because these two regions experienced a large number of armed conflicts in the last three decades (Fig. 1A)

Summary

Introduction

There is a suggested linkage between violent conflict and climate, the underlying mechanisms of the link are still under debate[1,2]. Suggest that climate has an indirect rather than a direct effect on violent conflicts 10 While these hypotheses were first studied in the context of civil wars and other stateengaged conflicts, research in the past decade on communal, non-state violence has emphasized the mediated pathways through which climate can influence conflict. This includes the potential for harmful climate anomalies like drought to drive conflicts in times of scarcity due to resource competition, lowered opportunity cost, or other mechanisms[11,12]. To assess climate impacts on violence and uncover whether the underlying mechanisms are direct, indirect, or a combination of both, ‘non-climatic’ effects must be isolated Some studies do this by pooling data across locations and applying statistical models that control for non-climatic factors explicitly. We hypothesize that comparing these two ethnically and culturally distinct, but yet geographically close regions may reveal contrasting mechanisms

Data and Methods

Assessing Direct and Indirect Causal Effects

Results and Discussion

D Middle East

Concluding Remarks