The major development banks are all involved in significant programmes for promoting clean energy investment. ( For example, for a review of development banks’ activities in the area of energy efficiency financing, see UNEP-FI (2009), “Energy Efficiency and the Finance Sector”.) The Organization of the Petroleum Exporting Countries (OPEC) has argued during international climate negotiations that a global energy transition would lead to lower incomes because, all else equal, the total volume of oil consumption would be lower in a carbon constrained world.