Description: This report analyzes the design of the cap-and-trade program as adopted by the California Air Resources Board (ARB). This new, complex program is part of the state's plan to reduce greenhouse gas emissions statewide to 1990 levels by 2020—a goal set by the Global Warming Solutions Act of 2006 (commonly referred to as AB 32). The report examines in detail the specific policy choices made by the ARB in the design of the program, some specific policy trade-offs inherent in those decisions, and options for program design changes that the Legislature may wish to make depending on its policy priorities.