Climate change continues to surface as a major issue in the Democratic presidential primary contest. And at a recent CNN debate, a sparring match over fracking provided one of the more talked about exchanges between Hillary Clinton and Bernie Sanders.

But such issues have come up less often on the Republican side—in part because there is more uniformity among the candidates. GOP frontrunner Donald Trump has called climate change a hoax orchestrated to benefit Chinese manufacturers. And recently, he told a crowd in New Orleans that he thinks he would win in New York because he supports fracking. The state’s Democratic governor, Andrew Cuomo, has banned it.

Marco Rubio has taken a similar stance—laying out an energy policy that would rely on drilling and fracking and would rollback efforts by the Obama administration to combat climate change.

“Every proposal that they put forward [is] going to make it harder to do business in America,” Rubio said during a CNN debate last September. “So we are not going to destroy our economy, we are not going to make America a harder place to create jobs, in order to pursue policies that will do absolutely nothing to change our climate, to change our weather.”

LISTEN: “Where Do the Republican Candidates Stand on Climate Change?”

Rubio has said he believes climate change is real but that it is not caused by human activity. Not so, for Texan Ted Cruz . He hosted a Senate hearing on climate change in December—during which he cited reasons he’s not convinced climate change is happening. One argument: Carbon dioxide is not a pollutant because it’s good for plants.

But Governor John Kasich has distinguished himself somewhat among the Republican candidates on the issue of global warming. When Kasich first hit the campaign trail last summer, Pope Francis had just published a historic environmental encyclical. In it, the Pope cast climate change as a moral issue and called on people to change their consumerist behaviors that contribute to the problem. Some GOP candidates criticized Francis for speaking out on political issues. But Kasich had a different response.

“I respect what the Pope said,” Kasich told a reporter from Undercurrent. “My feeling is what he said, that we have an obligation to the environment.”

The question for many is what a President Kasich would do about climate change. At a town hall meeting in New Hampshire in January, Kasich was asked again about his views on the issue.

“I think that human beings do affect the climate,” Kasich said. “And I’m a big supporter of solar and wind and geothermal and efficiency. But I want all of the different sources. I saw Seabrook today; I’m for nuclear too. I’m for all of this.”

WATCH: “Donald Trump Sounds Off On Fracking”

On the other hand, Kasich has come out against action by the Obama Administration to curb carbon emissions. Obama’s Clean Power Plan, which has now been put on hold by the U.S. Supreme Court, aims to cut a third of carbon emissions from the electricity sector by 2030.

“Let’s not go so fast that we throw this kid out of work or this gentleman out of work,” Kasich said at the event in New Hampshire. “It’s got to be a balance between a good environment and economic growth, which we can achieve.”

In Kasich’s home state of Ohio, two-thirds of electricity comes from coal, and Kasich has said the state will continue to burn coal without apology. Emissions from coal are considered the largest contributor to global climate change in the U.S.

“Governor Kasich is not necessarily your truest, bluest, greenest friend on the environment, nor is he an arch enemy of the environment,” says Jack Shaner of the Ohio Environmental Council, a citizen environmental group.

Kasich was slammed by environmental groups for freezing Ohio’s renewable energy program for two years. The program required utilities to replace some energy from coal with alternatives like solar and wind. But Shaner says without Kasich, the Republican legislature would have completely eliminated the clean energy mandate.

“Governor Kasich gets credit for salvaging and holding the wolf from the door so we did not suffer an outright repeal of our clean energy standards,” Shaner says. “But we were disappointed he wasn’t more active earlier in that debate, and [didn’t] exert his leadership to get the legislature to back down.”

“Governor Kasich is not necessarily your truest, bluest, greenest friend on the environment, nor is he an arch enemy of the environment.”

Kasich has split with some in his own party by pushing a tax on the oil and gas industry. There’s a similar debate over a gas tax in Pennsylvania, where many Republicans say it would drive the industry away. Kasich, however, sees things differently.

“I’m disappointed by those who say the severance tax reform will kill the industry,” Kasich said in his state of the state speech last year. “That’s a joke. That’s a big fat joke because I’ve talked to them in private. And I’ll tell you what, our severance tax will still be competitive with other energy-rich states.”

The Ohio Environmental Council praises Kasich for these efforts—and for preventing oil and gas drilling in state parks. Jack Shaner says Kasich has also put a lot of funding into reducing toxic algae in Lake Erie. On the other hand, Shaner says Kasich started something called the Common Sense Initiative that’s made it difficult to create new environmental regulation—especially if it comes at any cost to the private sector.

“This is sort of the mystique of John Kasich,” Shaner says. “You just cannot categorize the guy. He is complicated.”