ANN ARBOR, Mich. -

Two Michigan Girl Scouts have convinced Kellogg's to change an ingredient in their cookie recipe because they said its production destroys forest homes for endangered animals.

Ann Arbor's Rhiannon Tomtishen and Madison Vorva, both 15, said they became concerned when they found out that Girl Scout cookies were made with palm oil, something they say causing deforestation and habitat loss for orangutans and Tigers in Malaysia and Indonesia during its production on plantations.

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"Rain forest land which is their habitat in Indonesia and Malaysia is cleared so these palm oil plantations can be planted," Vorva said.

The two said they stopped selling the cookies and then stirred up an effort to get Kellogg's, the parent company of the Girl Scouts' bakers, to switch to a more environmentally-friendly alternative, like canola oil or olive oil.

"I think because we were Girl Scouts we felt really inspired to bring this issue and bring more attention drawn towards it and to try to convince the Girl Scouts to remove palm oil from their cookies," Tomtishen said.

A boost in their efforts came when the Union of Concerned Scientists wrote a letter to the Girl Scout organization and Kellogg's.

Then, in March, Kellogg's announced it would be be purchasing GreenPalm certificates for 100 percent of its palm oil use. These certificates are supposed to provide funds to encourage the growth of so-called "sustainable" palm oil, cultivated on land that wasn't deforested since 2005. Kellogg's also announced that it intends to eventually directly purchase "sustainable" palm oil.

"As a socially responsible company, Kellogg is committed to conducting our business in a way that reduces our environmental impact," said Celeste A. Clark, Ph.D., Kellogg's chief sustainability officer. "While palm oil is a very small percentage of our total ingredients, as a socially responsible company, concerns about the sustainable production of palm oil are clearly on our radar screen."

The two girls believe their efforts can teach a lesson.

"I think we learned through this project that whatever age you or where you are that you can make a difference and you don't have to start out with this grand goal. You can start small," Vorva said.

"If you're really passionate about something and you follow through with it, it will become as big as you can make it," Tomtishen said.

If you would like to learn more about the campaign, visit the Rainforest Action Network's website .