National Park Service Ranger Jeff Denny heads into a grove of redwoods off Highway 101 outside of Orick, California June 3, 2014. Reuters/Nick Adams

A group of arborists claim they've got part of the solution to slowing climate change: cloning trees. A group of "modern day Johnny Appleseeds" are cloning massive California sequoias and coastal redwoods and re-planting them worldwide, believing the trees are "ideal for absorbing greenhouse gases that drive climate change," the Associated Press reported Wednesday.

David Milarch, co-founder of Archangel Ancient Tree Archive, urgently wants to repopulate the planet's forests. His nonprofit group has cloned 170 types of tress over two decades of work and planted more than 300,000 of those trees in seven different countries.

"It's really a race against time," Milarch said. "If we start right now, we can go after climate change and reverse it before it's too late."

The arborists believe the massive size and lengthy lives of the California trees — Sierra Nevada sequoias can be nearly 300 feet tall and 3,000 years old — indicate they're ideal to absorb greenhouse gasses. Expert climbers, who scale the massive trees to collect the necessary samples, aid the cloning. The 66-year-old Milarch told the AP that science is beginning to bear out his ideas, but others were skeptical.

Todd Dawson, a professor of integrated biology at the University of California, Berkeley, told the news service he admires the effort but it's not clear if the massive trees truly have superior genes that help prevent climate change.

"That's one of the things about global warming — it's a global problem," Dawson told the AP. "You're going to have to plant a lot of trees to combat global warming."

Climate change is increasingly worrying. The first six months of 2016 were the hottest ever on record, according to NASA and National Oceanic and Atmospheric Administration. It's the third year in a row that has set a record. As the Arbor Day Foundation points out, "through the natural process of photosynthesis, trees absorb [carbon dioxide] and other pollutant particulates, then store the carbon and emit pure oxygen." A study published in 2007 however, found that more trees wouldn't necessarily mean decreased global warming.