SALINAS, Calif. -- A California political action group is spending thousands of dollars on a commercial aimed at curbing immigration by linking the population influx to the rising carbon footprint of the country.

The ad is funded by a nonprofit group called Californians For Population Stabilization.

The group's national media director, Rick Oltman, said the ad is designed to make people think and that it is coincidence that the spot is airing during the election season.

Oltman said immigrants cause four times more carbon emissions in the U.S. than in their home countries because they begin living the "consumer life" of Americans.

"Yes, they do have a footprint in their country of origin, but it's four times larger once they get in, start working in America and consuming in America," Oltman said.

Oltman said that while the ad is not a campaign plug, the nonprofit group can endorse legislation.

"Election seasons are certainly season for issues, or usually they are," Oltman said. "We'd hope that while people are issue-oriented and making decisions about the election, that they look at this issue."

California State University at Monterey Bay professor Dan Fernandez with the department of environmental studies said the statistics CAPS uses aren't off base, but that the larger issue is the footprint Americans themselves leave.

Fernandez said that in 20 to 30 years, developing countries will be increasing their carbon footprint as well, and it's important to look at the big picture.

The statistics used in the CAPS ad are based on a study by the Center for Immigration Studies, based in Washington, D.C.