On the eve of a pair of crucial Southern primaries, GOP presidential hopeful Rick Santorum turned his attention to the environment.

The former Pennsylvania senator focused on energy development in Mississippi, prodding voters to trust his judgment.

"The dangers of carbon dioxide? Tell that to a plant, how dangerous carbon dioxide is," he said.

Santorum has used the environment as a talking point in criticisms of both his GOP rivals and President Barack Obama's administration. Back in early February, he targeted Mitt Romney and Newt Gingrich for allegedly buying into the "bogus" science of man-made climate change. At the same time, Santorum placed himself as a candidate who never believed in the "hoax of global warming."

A few weeks later, Santorum shifted to Obama's energy plans, telling a group of Ohio voters that global warming is not climate science but "political science."

Entering Tuesday's Alabama and Mississippi primaries, Romney holds a 454-217 delegate edge over Santorum. In total, 1,144 are needed to secure the GOP presidential nomination.