As part of its review of its environmental marketing guidelines (the "Green Guides"), the Federal Trade Commission will host a public workshop on carbon offsets and renewable energy certificates (RECs) on Tuesday, January 8, 2008, from 9:00 am to 5:00 pm at the agency’s satellite building in Washington, DC. At the workshop, FTC staff will explore advertising claims as well as issues of consumer perception, substantiation, and self-regulation. A webcast will be provided for those unable to attend in person; for more information visit