In this June 20, 2014 file photo, Sen. John Thune, R-S.D., speaks at the South Dakota Republican Convention in Rapid City, S.D. (AP Photo/Toby Brusseau, File)

For too long, the country’s debate on climate change has been stuck on whether the phenomenon is happening at all, or on whether humans are responsible for it. As a Post editorial noted Monday, Republicans are mostly to blame for this, and key GOP leaders still seem unwilling to move the discussion forward now that they have won control of Congress.

It is in this dismal context that comments from Sen. John Thune (R-S.D.) on Fox News Sunday offer a glimmer of hope that at least some Republicans aren’t comfortable with their party’s role in the debate.

Asked about the overwhelming agreement among experts on the cause and trajectory of global warming, Thune began with a familiar GOP climate-change dodge: “Climate change is occurring, it’s always occurring.” But then he said this: “There are a number of factors that contribute to that, including human activity. The question is, what are we going to do about it and at what cost?”

In three sentences, the number-three Republican in the Senate admitted that human activity is affecting the climate and that this concern demands a policy response.

This is progress for Thune, who said this in 2010: “Obviously, I think the question you have to ask yourself, one, is it occurring? And even if you say ‘yes’ to that, two, is human activity contributing to it? And even if you say ‘yes’ to that, then three is what are we going to do about it and at what cost?”

But once you get to “yes” on the first two, as Thune apparently has, the answer to the last question should be relatively simple for honest conservatives: The efficient, market-friendly approach to cutting dependence on greenhouse gases is pricing carbon dioxide emissions and allowing market forces to adapt the economy.

Thune didn’t go there, and that’s also a problem: Republicans have to do more than simply acknowledge that there is a risk. His statement might be merely another GOP attempt to justify doing too little without seeming anti-science. Even so, it’s much better than other recent GOP responses to questions on climate change, such as Mitch McConnell’s “I’m not a scientist.” That’s just nonsense. By contrast, Thune’s formulation points in a sure direction: It will be ultimately untenable for Republicans to admit that global warming is a legitimate concern yet reflexively attack efforts to deal with it.

The country can do better than the GOP’s do-little-or-nothing attitude, and it can do better than President Obama’s regulatory approach to cutting emissions. But only if more Republicans ask the right question — instead of continuing to dignify those who demand that their leaders dismiss and disdain scientists’ warnings.