There have been nine wars and almost 130 violent conflicts across the world this year, according to an annual report released on Monday December 15th by the Heidelberg Institute for International Conflict Research, a think-tank. The study classifies conflict broadly to include peaceful disputes over politics or borders (low intensity), as well as those involving sporadic or constant violence (medium or high intensity). In 2008 previously non-violent conflicts escalated into violence in countries such as Kenya and Yemen. Ideological change is both the most common cause of conflict and the root of most wars, but there is rarely only one cause of dispute. Congo's ongoing conflict encompasses a battle for its mineral resources and, according to some, an invasion by another state, Rwanda.