A recently released draft report (PDF) prepared for the United Nations makes an ambitious attempt at showing how 15 major carbon-emitting countries, including the United States and China, can make deep reductions in their emissions to help keep global temperatures from increasing more than 2°C above preindustrial levels — a goal at the heart of international climate negotiations. Prepared by a group of independent international experts, it confirms that a variety of low-carbon technology solutions are already available.