Mayors from throughout the nation gathered in Dallas this weekend to take a step toward addressing the phenomenon that NASA says 97 percent of climate scientists agree is caused by the day-to-day lives of humans: climate change.

Lubbock Mayor Glen Robertson was not among them.

Previous Lubbock mayors have taken part in the U.S. Conference of Mayors, but Robertson said the $20,000-$25,000 it costs to participate in the organization does not provide enough benefit to the city.

"I don't know that it does the city any good, and I sure don't think we get a return on our investment," he said. "I just opted to not be a part of it."

More than just the expense, Robertson described the organization as a lobbyist group led by "left-leaning" city leaders.

"Anything that they do really doesn't have any teeth in it," he said. "They can't pass any laws or any ordinances, all they can do is meet."

And, in order to address the issues of global warming, you must first "buy in to climate change."

"All of the world's scientists are still in disagreement," Robertson said. "We all know there is climate change, we just don't know if it is manmade or if it is cyclical or what is really going on."

Further than the cause of the natural phenomenon, Robertson is also skeptical cities can do anything to combat it at the local level.

Still, the resolution to encourage cities to use nature to "protect freshwater supplies, defend the nation's coastlines, maintain a healthy tree and green space cover and protect air quality," sometimes by partnering with nonprofit organizations was passed unanimously at the conference.

The resolution was backed by Democratic mayors from GOP-dominated states - Austin Mayor Lee Leffingwell, Houston Mayor Annise Parker and Phoenix Mayor Greg Stanton.

It passed easily despite a deep divide between Republicans and Democrats on the issue - though science shows human industrial activity is contributing to global warming, some conservatives remain skeptical.

"What's so significant is that there was a unanimous vote on an issue that can be so divisive," said Laura Huffman, director of The Nature Conservancy in Texas. "When you peel away the high-level arguments and deal with the ground-level issues everyone just rolls up their sleeves and gets to work."

Mayors are looking for alternatives to traditional infrastructure projects that will be cost-effective and provide residents with amenities.

For example, Huffman said, Philadelphia Mayor Michael Nutter is combining traditional pipes with open spaces as he revamps the city's storm water collection system. These open spaces collect water much like pipes do, while providing residents with additional parks.

"We're seeing that all over the country," Huffman said.

Avalanche-Journal reporter Stevie Poole contributed to this story.