GREENSBORO, North Carolina (AP) -- Democratic presidential candidate John Edwards said Tuesday his campaign would seek to eliminate its contribution to global warming by becoming "carbon neutral."

Speaking to a crowd of college students at Bennett College, the former North Carolina senator urged all Americans to help reduce the emissions of carbon dioxide and other greenhouse gases.

"It's time for the president of the United States to ask Americans to be patriotic about something other than war," Edwards said. "This is an emergency. This requires action now."

Edwards said his campaign will consult with experts to calculate its total carbon emissions -- covering everything from his campaign travel to the energy used at his headquarters office in Chapel Hill.

Along with taking a series of steps to improve its energy efficiency, the campaign will buy carbon offsets, or credits sold by those who have reduced their emissions of carbon dioxide. He declined to give an estimate of how much the offsets might cost, other than to say it would be expensive.

Edwards said that while the United States is home to 4 percent of the world's population, the country is the source of roughly one-quarter of the world's greenhouse gas emissions.

"We are not a good example for the world," he said. "We need to start by cleaning up our own house."