"The market is growing fast. We're hoping for commonly accepted standards in coming months," said Renate Heuberger, managing director of Swiss-based myclimate.org which is helping soccer's governing body FIFA at the World Cup finals in Germany.

FIFA plans to offset 100,000 tons of carbon dioxide linked to travel by World Cup spectators. Under one project, it and the German tournament organizers will invest in replacing coal-fired boilers at a South African factory with boilers run on sawdust.

Some environmentalists are skeptical of the offset projects, particularly forest plantings since they say many saplings die.

They want the world to focus on axing fossil fuel use.

"'Plant a tree and fly guilt-free' is obvious nonsense," said Steve Sawyer of Greenpeace.

Yet with growing public concern about global warming, some businesses find that it pays to go green.

HSBC says it became the world's first carbon neutral bank in 2005 by investing in clean energy projects such as a wind farm in New Zealand to offset emissions from its core operations.

HSBC bought 170,000 tons of carbon dioxide for $4.4 per ton for the fourth quarter of 2005, a total of about $750,000. Some environmentalists say HSBC should extend its scheme, which excludes the carbon impact of its loans.

Gore's movie calls itself the "first carbon neutral documentary." But Gore was criticized after he was spotted driving 500 meters to a screening at the Cannes film festival.

The World Bank said this month it would offset 148,000 tons of emissions to become "carbon neutral."

The projects are springing up in parallel to the

United Nations' Kyoto Protocol, which obliges 35 industrial nations to cut emissions by 5.2 percent below 1990 levels by 2008-12.

President George W. Bush pulled the United States out of Kyoto in 2001, saying it would cost jobs and wrongly excludes developing nations. The United States is the world's number one source of carbon dioxide, emitting about 24 tons per person.

"If you only look at U.S. politics you miss how much the average person has a concern for these issues," said Jack Groh, director of the National Football League's environment program.

organizers of the Super Bowl, won by the Pittsburgh Steelers in Detroit in February, planted enough tree seedlings to cover 3.5 acres and soak up 260 tons of carbon.

BEWILDERING VARIETY

World Cup organizers are buying "certified emission reductions" (CERs) created by a Kyoto scheme for promoting investments in clean energy in developing countries, with an additional quality stamp known as the "gold standard."

"This is a market with very different currencies, we believe that CERs will be the benchmark," Heuberger at myclimate said.

He said that CERs bought for the World Cup cost almost 10 euros (US$12.58) a ton. In a

European Union market set up under Kyoto, prices are around 15 euros a ton.

Shopley's company -- founded before Kyoto started -- relies mostly on "verified emissions reductions" (VERs), checked by external auditors but often cheaper than CERs. VERs are often energy projects too small to qualify for Kyoto mechanisms.

For travelers, Web sites can be bewildering.

For one passenger flying from Paris to Sydney, for instance, Carbon Neutral reckons emissions are 1.9 tons, but Germany's Atmosfair reckons the emissions total 5.99 tons, due to a "high altitude surcharge."