The current global energy system faces multiple pressing issues. Competition for limited natural resources such as energy, water, and land has risen to the center of global strategic concerns due to the emergence of new economic powers, a rapidly growing and urbanizing population that could top 9 billion by 2035, and, increasingly, climate change. A timely transition to a sustainable global energy system is urgently needed. However, there is little knowledge and a lack of common understanding of the issues facing the global energy system amongst energy sector players, investors, policymakers, and researchers. GMF has established the Energy Transition Forum – a project which aims to generate new thinking and creative dialogue on how to address the key challenges facing the energy system — in response to these pressing energy dilemmas. This Energy Transition Forum reference document outlines the underlying trends and dilemmas that have prompted GMF to undertake the initiative.