A rapidly growing body of research examines whether human conflict can be affected by climatic changes. Drawing from archeology, criminology, economics, geography, history, political science, and psychology, we assemble and analyze the 60 most rigorous quantitative studies and document, for the first time, a remarkable convergence of results. We find strong causal evidence linking climatic events to human conflict across a range of spatial and temporal scales and across all major regions of the world. The magnitude of climate's influence is substantial: for each 1 standard deviation (1σ) change in climate toward warmer temperatures or more extreme rainfall, median estimates indicate that the frequency of interpersonal violence rises 4% and the frequency of intergroup conflict rises 14%. Because locations throughout the inhabited world are expected to warm 2-4σ by 2050, amplified rates of human conflict could represent a large and critical impact of anthropogenic climate change.

Quantifying the Influence of Climate on Human Conflict

IS WAR NECESSARY FOR ECONOMIC GROWTH? Military Procurement and Technology Development

Breaking the Conflict Trap in India’s Northeast

Abstract Data for discrete ordered dependent variables are often characterised by “excessive” zero observations which may relate to two distinct data generating processes. Traditional ordered probit models have limited capacity in explaining this preponderance of zero observations. We propose a zero-inflated ordered probit model using a double-hurdle combination of a split probit model and an ordered probit model. Monte Carlo results show favourable performance in finite samples. The model is applied to a consumer choice problem of tobacco consumption indicating that policy recommendations could be misleading if the splitting process is ignored.

A zero-inflated ordered probit model, with an application to modelling tobacco consumption

This dissertation is a collection of studies on the economics of peace and security. Chapter one introduces the roles military spending and conflict play in affecting economic growth, while also considering the causes of civil conflict. Chapter two investigates the relationship between military expenditure and economic growth, considering group heterogeneity and non-linearity. Using an exogenous growth model and dynamic panel approach, the results suggest military burden to have a negative effect on growth. Breaking the overall panel down into various sub-samples shows estimates that are remarkably consistent with the full panel. These results provide strong support for the argument that military spending has an adverse effect on growth. There are, however, some intriguing results suggesting that for certain types of countries military burden has no negative growth effect. Chapter three deals with the transnational spatial spillover effects of conflict on neighbouring countries. It moves beyond using geographical distance as a spillover measurement and allows for economic and political distances. The initial empirical results suggest that conflict has a strong negative spillover effect on directly contiguous countries growth, but no significant impacts were observed for non-contiguous countries. When economic and political factors are considered, this result remains, but the spillover effect is smaller. While the impact of conflict remains devastating, it is important to take other factors into account as studies using only geographical distance may be overestimating the impact on neighbours. The fourth chapter examines the determinants of civil war, using a zeroinflated modelling approach to deal with excess zeroes in the dependent variable. Traditional probit and logit models have limited capacity in dealing with this issue and can create misleading results, which is illustrated through replicating published work. A general greed-grievance model is then estimated giving further support to using zero-inflated models. While the standard probit models tend to emphasise opportunity variables, consistent in other studies, the zero-inflated model gives supports both opportunity and grievance variables. In particular, ethnicity, democracy and inequality are found to play a significant role in civil war prevalence. Finally, chapter five summarises the findings of the dissertation, providing some policy recommendations, concluding remarks and discusses future research opportunities.

Nan Tian

Papers

The economics of military spending, conflict and growth