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Can Natural Disasters Incite Terror?

Final Report Summary - NDTERROR (Can Natural Disasters Incite Terror?)

The goal of this project during its first period was to provide identification and empirical quantification of the effect of natural disasters on terrorism, explore the different possible mechanisms at play, analyze the timing and geospatial correlates, and whether there are differing effects by various disaster types.
The goals of this project during its second (and final) period was to use the causal effect of natural disasters on terrorism as an exogenous instrumental variable in the analyses of the effect of terrorism on differing factors of interest. In particular the aim was to study the causal effect, directionality and magnitude of the links between terrorism and labor market outcomes, such as the female labor force participation, the male-female labor gender gap, as well as other economic and demographic decision outcomes such as fertility and birth rates. Results were then analyzed to assess the policy implications that could contribute to the most effective and appropriate strategies for mitigating terrorist actions.

All of the anticipated project's objectives of the project were achieved successfully. The main findings are summarized in five peer reviewed publications.

These publications are,

1. "Earthquake, Hurricanes, and Terrorism: Do Natural Disasters Incite Terror?." published in Public Choice, Vol. 149 (3–4), pp. 383–403, December 2011 (by C. Berrebi and J. Ostwald)
2. "Exploiting the Chaos: Terrorist Target Choice Following Natural Disasters." published in the Southern Economic Journal, Vol. 79 (4), pp 793–811, April 2013 (by C. Berrebi and J. Ostwald).
3. "Predicting Suicide Attacks: Integrating Spatial, Temporal and Social Features of Terrorist Attacks Targets." published in RAND Publications, 2013 (by W. Perry, C. Berrebi, R. A. Brown, J. Hollywood, A. Jaycocks, P. Roshan, T. Sullivan, L. Miyashiro)
4. "Terrorism and Fertility: Evidence for a Causal Influence of Terrorism on Fertility” published in Oxford Economic Papers, Vol. 67 (1), pp. 63-82, January 2015 (by C. Berrebi and J. Ostwald).
5. "Terrorism and the Labor Force: Evidence of an Effect on Female Labor Force Participation and the Labor Gender Gap” forthcoming in The Journal of Conflict Resolution, 2015 (by C. Berrebi and J. Ostwald).

In "Earthquake, Hurricanes, and Terrorism: Do Natural Disasters Incite Terror?." published in Public Choice, December 2011, Vol. 149 (3–4), pp. 383–403 (by C. Berrebi and J. Ostwald), we, for the first time, assessed empirically whether natural disasters have an effect on terrorism. Using detailed information on terrorism, natural disasters, and other relevant economic and demographic variables of 167 countries between 1970 and 2007, we were able to identify and estimate the effect of natural disasters on terrorism. We found that disasters have a strong positive association with subsequent terrorism incidence and fatalities. When focusing on the type of disaster, we found differences between the effects that can be attributed to the variation in predictability and deadliness of the disaster types. Differing impacts on infrastructure, early warning systems, and seasonal expectations for meteorological events tend to influence the outcomes. By breaking down our data into groups based on GDP per capita, we were able to further isolate our effect to identify the country types in which the phenomenon has been most prevalent. We found that natural disasters primarily affected terrorism in low to middle GDP per capita countries with effects most concentrated in poorer, low GDP per capita, countries. Additionally, the findings indicated countries with particularly high GDP per capita did not experience terrorism following a natural disaster.
The results of this study present compelling evidence that a reduction in the impacts of disasters could prevent substantial escalations in terrorism. Investments in prevention, resiliency, and international cooperation towards disaster mitigation could produce potentially significant security benefits. Our policy analysis reveals that efforts should be made to address some of pre-existing societal factors that make countries more susceptible than others to both disasters and terrorism. Despite great efforts by policy makers, over the last decade, to emphasize the establishment of security ties between countries to combat terrorism, cooperation against non-military threats like natural disasters has remained inchoate. While previous strategies have by and large considered these threats disjointly. Our findings suggest this can no longer be. Future policies for thwarting terrorism must also include efforts in order to understand and bolster resiliency to natural disasters. In that way we might attenuate the devastating consequences of both.

In "Exploiting the Chaos: Terrorist Target Choice Following Natural Disasters." published in the Southern Economic Journal, April 2013, Vol. 79 (4), pp 793–811 (by C. Berrebi and J. Ostwald), we explored the differences between transnational and domestic terrorism, further differentiating by private versus government targets, to estimate the effect of exogenous catastrophic shocks on a country’s level of domestic and transnational terrorism. The empirical analysis used detailed data on terrorism, natural disasters, and other relevant controls for 176 countries from 1970–2007 to illuminate several key disparities in a post-disaster target choice of terrorists. The results indicate that natural disasters incite both transnational and domestic terrorism. However, evidence is found for dissimilar motivations between the two. While both types of terrorism increase after disasters, transnational attacks against the government increase immediately following the disaster, suggesting an impetus to exploit weakened ‘‘hard’’ targets during the chaos. Conversely, domestic terrorism against the government takes longer to manifest, suggesting a period of time for which the public recovers and assesses the government’s response.
This analysis significantly expanded upon research on the links between natural disasters and terrorism. Using a version of the GTD, which allowed for the distinction between transnational and domestic terrorism, the research determined that the effects of disasters were not limited to domestic terrorism but spanned across both types with differing effects. The disparities in effects appeared to be directly explained by target choice and timing. While attacks against private targets, disasters exerted very similar effects on both domestic and transnational terrorism this was not the case for attacks against government targets. The timing of attacks against the government differed significantly between ‘‘homegrown’’ and international terrorism. In particular, transnational terrorist activity against the government increased significantly in the year of the disaster but diminished in subsequent years. For domestic incidence, the opposite was true, with terrorist activity taking longer to manifest. The disparity in results indicated that disasters tend to trigger different underlying motives between the groups.
In sum, the analyses of this study confirm that both ‘‘homegrown’’ and international terrorist activity rise following disasters, suggesting that these incidents are not rooted solely in domestic grievances but a combination of frustrations with the government, societal grievances, and exploitable opportunities. Establishing mutual agreements between neighboring countries to assist in border security and stability efforts after a disaster could be a potentially fruitful venture that deserves consideration. Perhaps most important are the implications of the differential effects of disasters on transnational versus domestic attacks against the government. They suggest that states must be acutely aware of transnational groups attempting to exploit weaknesses immediately following a disaster while also being careful to deliver the best possible disaster response in order to head off the potential for future domestic discontent.

In "Predicting Suicide Attacks: Integrating Spatial, Temporal and Social Features of Terrorist Attacks Targets" published in RAND Publications, 2013, the aim was to develop ways to predict what determines the targets of suicide attacks. In order to enhance the predictive ability we incorporated sociocultural, political, geospatial, economic, and demographic factors, many of these were added on the basis of my findings regarding the different covariates in this project (based on the two mentioned above articles). Doing so helped us consider the most appropriate factors at risk, and contributed heavily to the performed qualitative and quantitative analyses. The specifics of the research were limited to the preferences of Palestinian suicide bombers in Israel. However, the methods used to assess target preferences in Israel can be transferred to other countries and results, could be used to develop recommendations for heightened public awareness in certain areas. This study, and the use of my earlier results provide one clear example of both the transfer of knowledge and the impact of the two earlier mentioned studies.

In "Terrorism and Fertility: Evidence for a Causal Influence of Terrorism on Fertility” published in Oxford Economic Papers, January 2015, Vol. 67 (1), pp. 63-82 (by C. Berrebi and J. Ostwald), we used a panel data set of 170 countries and terrorism data from 1970-2007, and found that terrorist attacks decrease fertility as measured by both total fertility rates and crude birth rates. Furthermore, by using a novel instrumental variable approaches, we identified a causal link and addressed endogeneity concerns related to the possibility of stress caused by rising birth rates, or transitioning demographics, affecting terrorism. We found that, on average, terrorist attacks decrease fertility, reducing both the expected number of children a woman has over her lifetime and the number of live births occurring during each year, per 1,000 population. The results are statistically significant and robust across a multitude of model specifications, varying measures of fertility, and differing measures of terrorism.

In "Terrorism and the Labor Force: Evidence of an Effect on Female Labor Force Participation and the Labor Gender Gap”, forthcoming in The Journal of Conflict Resolution, 2015 (by C. Berrebi and J. Ostwald), we used a similar panel data set of countries, focusing on labor markets and terrorism data from 1980-2007, we found that terrorist attacks decreased female labor force participation and increased the gap between male and female labor force participation. By exploiting variation across countries and time, we were able to identify the effects of terrorism on female labor force participation and the labor gender gap. Furthermore, by using a novel instrumental variable approaches, we identified a causal link and addressed endogeneity concerns related to the possibility of transitional development and shifting gender relations inciting terrorism. We found that, on average, terrorist attacks significantly decreased female labor force participation, ultimately widening the labor gender gap. The results are statistically significant and robust across a multitude of model specifications.


With respect to personal professional accomplishments, my promotion procedure was just recently completed and I have to thank the Marie Curie funding for enabling the achievements and successes as reflected by the quality of my publications as well as my other research activities. In conclusion I was promoted to the position of tenured Associate Professor at the Hebrew University’s School of Public Policy.