Mary D. Nichols, 64

Environmental law

As chair of the state Air Resources Board, Mary Nichols is a key player in crafting California's groundbreaking climate change regulations. This year, the environmental attorney led the board in approving the nation's first low carbon fuel standard. In the coming year Nichols has an even bigger challenge and one that will be closely watched from Washington, D.C., where lawmakers are considering a federal climate change law. The board will be creating a framework for a complex carbon emissions trading scheme, called cap and trade, to help ratchet down greenhouse gas emissions while keeping both environmentalists and the state's major industries on board.