Mary Jane Parks does her part to help the environment. She turns her lights off and walks whenever she can.
"I buy energy-efficient appliances, and I take a reusable canvas bag to the grocery store," says Mary Jane.
But despite all those efforts, she knows there's no way to totally stop polluting the atmosphere. So Mary Jane tries to minimize the damage she causes by buying what's called a carbon offset.
"A carbon offset is something that represents a reduction in greenhouse gas emissions," said Jennifer Martin of the Center for Resource Solutions.
To get one, head to any number of new Web sites and donate money to a program that funds clean energy projects - like wind farms and forest renewal - designed to counterbalance your carbon emissions.
Environmental groups like the Center for Resource Solutions say offsets are a valuable tool in the fight against global warming, but there are concerns.
"Consumers can't tell they actually received an offset because it's invisible," said Martin . "They can't hold it or see it."
Right now, there is no government oversight to make sure donations are invested as promised, or that the offsets actually perform as promised. Martin wants that to change.
"I think at a minimum, regulation should enforce that when companies are selling products where they're making claims about greenhouse gas performance or climate neutrality of a product, that there's real data and verification to back that up," said Martin.
For the first time, the Federal Trade Commission is looking into the exploding industry and is exploring possible guidelines.
"What we want to do is make sure that we give clear guidance on how to truthfully market these products, and make the rules of the road clear so the market can function effectively for consumers," said James Kohm of the Federal Trade Commission.
TerraPass, one of the largest carbon offset companies, welcomes any oversight.
"I think it will add a lot to consumer confidence. I'd like to see a nice simple set of disclosure rules so that consumers know consistently what they're paying for," said Erik Blachford of TerraPass.
Until guidelines are established, experts say you should look for verification from an independent third party, such as the Center for Resource Solutions.
Some of the companies are not-for-profit and others are for-profit. When picking a company to offset your energy use, experts suggest finding out what percentage of your donation will actually go to the cause.
Some examples of carbon offset companies:
- Bonneville Environmental Foundation
- Better World Club, Inc.
- The Climate Trust
- Sustainable Travel International