"The United Nations Environment Programme (UNEP) suggests that in the last 60 years, at least 40% of all intrastate conflicts have a link to natural resources, and that this link doubles the risk of a conflict relapse in the first five years. Since 1990, at least 18 violent conflicts have been fueled by the exploitation of natural resources, whether high-value resources like timber, diamonds, gold, minerals and oil, or scarce ones like fertile land and water. Climate change is not a direct source of conflict, but is seen as a threat multiplier that exacerbates resource scarcity and existing vulnerabilities."
(https://peacekeeping.un.org/en/conflict-and-natural-resources)