•A California promoter who launched a ship to spread iron dust in the South Pacific to grow carbon-sucking algae, a plan that the Environmental Protection Agency said would amount to illegal dumping at sea.
•An Israeli charity that is selling offsets that are supposed to create brand-new projects, for tree plantings it has been doing for 60 years.
Such examples are causing some supporters of carbon offsets to back off what they once saw as a promising tool to help the environment. And the troublesome record concerns those who want a national carbon cap-and-trade program in the US that would use offsets.
Some consumers are becoming wary. The US House of Representatives dropped plans to make its Capitol offices “carbon neutral” last year after spending $89,000 on offsets. Nike shoes abandoned them this year as untrustworthy. Responsibletravel.com, a British travel agency that claimed to be the first to offer carbon offsets in 2002 as a centerpiece of its business, has quit relying on them to help the environment. Instead, the company urges its clients to fly less.