AMSTERDAM, Netherlands - The United States is moving toward the regulation of carbon emissions, a U.S. energy official said Thursday, despite the Bush administration's adherence to a voluntary approach to controlling the primary gas blamed for climate change. "There will be carbon regulation of some sort," said Dan Arvizu, director of the National Renewable Energy Lab of the Department of Energy, told an international conference on biofuels. He spoke a week after briefing President Bush's global warming conference of major carbon-emitting nations. "I am neutral as to which kind of carbon management regulation there will be. It is very clear...