As Congress considers legislation to address climate change, and follows negotiations toward a new international agreement to reduce greenhouse gas (GHG) emissions, the question of the comparability of actions across countries frequently arises. Concerns are raised about what the appropriate sharing of efforts should be among countries, as well as the potential trade implications if countries undertake different levels of GHG reductions and, therefore, incur varying cost impacts on trade-sensitive sectors. All countries examined have in place, or are developing, some enforceable policies that serve to reduce GHG emissions. This book presents an overview of GHG control policies within effect or under consideration in a number of large countries and offers a brief set of intitial observations.