For many decades, and in particular after the start of the Cold War, the field of geography has focused on the physical, environmental and social influences on war. Conflict geography is a subfield concerned with understanding conflict in various regions. One example of research has shown how in ethnic conflicts the concentration of ethnic groups facilitates group coordination for collective action. In other words, people from the same ethnic group who live closely are more likely to instigate and organize each other to fight rival ethnic groups, whereas ethnic groups more dispersed within a country are less likely to lead to intrastate conflict due to a lack of coordination.
A lack of geographic understanding in post-World War I planners has often been cited as a reason why major conflicts persist in the Middle East today. When boundaries were demarcated, political planners categorized and assigned political characteristics according to their ideas of national political geography. However, this did not focus on ethnic and cultural variation within the region, leading to rivalries and further political fracturing affecting today’s wars in the Middle East. Works have looked at historical reasons for war and how geography has played a role. For instance, countries in defensive areas, where mountains are high and difficult to traverse, have had less conquest in their histories, limiting the impact war and its trauma has had on populations. Other regions, with their open, expansive plains, have had to develop and invest more on the military because of perceived vulnerability, affecting those countries economies and viewpoints on outside powers. Other approaches have looked at the physical environment and its role in fueling conflict. A study looking at long-term human history found that deviations from normal precipitation and mild temperatures systematically increase the risk of conflict, showing that human conflict and climate have influenced each other throughout history. Such results are still controversial, but they are beginning to show how physical and social factors shape global conflict today and in the past.
 For more on the effects of high concentration of ethnic groups in locations and the role of geography and organization in motivating conflict, see: Weidmann, N. B. (2009). Geography as Motivation and Opportunity: Group Concentration and Ethnic Conflict. Journal of Conflict Resolution, 53(4), 526–543.
 For more on the role geography plays in understanding long-term conflicts such as in the Middle East, see: Smith, L. V. (2016). Drawing Borders in the Middle East after the Great War: Political Geography and “Subject Peoples.” First World War Studies, 1–17.
 For a historical analysis on how geography has affected conflict and how it shapes societies, see: Van Evera, S. (1999). Causes of war: power and the roots of conflict. Ithaca: Cornell University Press.
 For more on climate and conflict, see: Hsiang, S. M., Burke, M., & Miguel, E. (2013). Quantifying the Influence of Climate on Human Conflict. Science, 341(6151), 1235367–1235367.