Jan. 9, 2008 -- The Federal Trade Commission is raising questions about green marketing claims surrounding carbon offsets. The commission, which is currently revamping its guidelines on environmental advertising, is concerned that "there's a heightened potential for deception," the New York Times reports.

FTC has not updated its green-marketing guidelines since the 1990s, when terms like "renewable energy," "carbon offsets." and "sustainability" were not yet in vogue. In recent years, however, carbon offsets have become the centerpiece of many corporate climate-management programs.

Critics of carbon offset programs point to disagreement over how much carbon dioxide can be neutralized by offset activities such as tree-planting. In addition, many are concerned that offset providers are "double-counting" greenhouse gas reductions that would have happened on their own.

During the hearing, FTC cited the public backlash against the Super Bowl, which has previously been billed as "carbon neutral," as a case in point. The National Football League has drawn criticism for the way its carbon offsets were handled.

FTC is currently gathering information on how carbon offset programs work.

For a transcript of the FTC hearing, click here.