Sens. John Kerry (D-MA) and Joe Lieberman (I-CT) recently introduced long-awaited Senate climate change legislation. The bill seeks to reduce greenhouse gas emissions in the United States by 17 percent of 2005 levels by 2020 and 83 percent by 2050, matching targets set in a House bill passed in 2009. The bill includes several provisions calling for transparent and participatory policies, especially relating to measures that would create new financial markets for buying and selling the right to pollute. How well such transparency would be implemented is a major question, and the success of the emissions reductions may depend on the level of openness that is built into the nation's climate change policy.