Recently, we ran a segment here at The World in which I talked with our host Marco Werman about four news items from around the world that were all small links in the much larger global chain of stories about coal, carbon dioxide, and climate change.

The next day we got a complaint. It was one of those letters well-known to any news organization that makes a serious effort to cover climate change. The gist is that PRI's The World blindly accepts a bogus scientific consensus on “the AGW (anthropogenic global warming) notion.”

“Mr. Thompson [sic] and PRI should investigate what they are promoting. What they will find is that there is no reason to believe that global temperature and climate are affected any more than tangentially by CO2 concentration. Most certainly it has never been proved that there is any relationship between them, and Mr. Thompson’s authoritative pronouncements (IIRC) on the subject should always be prefaced with ‘Some people believe’ rather than flatly making the mistaken statements that he has (again IIRC, he stated that CO2 causes global warming)… The facts are strongly against what Mr. Thompson has stated on air. His pulpit should be taken away from him.”

The note prompted one of my colleagues to send me a note of her own: “You know, I’d love to get your smart and short answer to guys like this.”

It’s a variation on a question that swirls around a lot of newsrooms and, I’m sure, in the minds of many of our listeners/readers: How do we know what we know about climate change? Isn’t there still a debate over whether climate change is real, and if so what’s causing it? Why don’t we give more attention to the “skeptics?”

Climate science is maddeningly complex and even its fundamentals often outstrip the basic physics and chemistry most of us got in school. So it’s no wonder that journalists who don’t cover it regularly struggle to understand it. Even those of us who have been covering it for years are constantly challenged to keep up with its subtleties, finer points, grey areas and cutting edges, as well as the areas of genuine debate.

But on the fundamentals of climate change, there is no longer any serious scientific debate — the basic cause-and-effect principles are well understood and the evidence for the trajectory of rising average global temperatures is overwhelming.

However, there is a political debate — masquerading as a scientific debate— backed by immensely wealthy and powerful interests. And these folks have been extremely successful in muddying the popular understanding of both the science and the consequences of climate change.

So here is my reply to my colleague and anyone else who is interested:

I’d tell guys like this that every major national scientific academy in the world, and the vast majority of other credible and relevant scientific organizations, endorse the CO2-temperature link. It’s been demonstrated and proven for decades.

Then there’s the IPCC (Intergovernmental Panel on Climate Change), which, despite claims to the contrary based mostly on extremely small and marginal errors, accurately represents the consensus of thousands of scientists around the world.

I’d also remind him that science is a dynamic and ultimately self-correcting process and that while much remains unknown and uncertain in the unfathomably complex global climate system, and while many specific findings, projections and theories regarding climate change are and will continue to be proven wrong, the overall science and the physical and chemical principles behind it have been vetted more thoroughly than perhaps any others.

While it’s important to lay out the uncertainties when you get to specific parts of the science and projections, the basic science stands up and is overwhelming in its fundamental conclusions. Saying “some people believe” that levels of CO2 in the atmosphere affect the climate system is as absurd as saying that “some people believe” in evolution by natural selection or that “some people believe” in the laws of motion, gravity, thermodynamics, etc.

“Some people believe” that all of those things should be challenged, but they all have been proven beyond a reasonable doubt. To suggest that journalists should somehow recapitulate the status or process of this proof, or acknowledge the objections of fringe elements in every mention of the issue, is to ask us to go down a rabbit hole of endless explanation of established fact, diverting time and resources from our real work. Which I’m fairly certain is what this fellow and other “skeptics” want.

And that’s why I actually wouldn’t bother telling him any of this, or anything else, because, while I’m not familiar with him in particular, the vast majority of folks like him who claim to debunk well-established climate science aren’t driven by facts or the scientific process, but by economic interests and/or ideologies. They don’t like the policy implications that climate science suggest for many people — primarily that we have to change the way we produce and use energy and other resources.

If they were intellectually honest, these folks would say, "yes, this is happening, but the costs to the economy or personal freedom, etc., of changing it are too high, so we shouldn’t even try." The problem is that, with most people, that would be a losing argument, so instead these folks try to undermine public understanding of the science and deliberately waste the time of scientists and journalists.

Which is why I’m not taking the bait anymore.

By the way, a great site/app for evaluating the assertions of climate “skeptics” is Skeptical Science, run by an Aussie named John Cook who has a BA in physics and also happens to be an evangelical Christian.

Update on June 27, 2012: Yesterday, a federal appeals court summed up my basic argument in two simple, direct sentences in upholding the EPA’s decision to regulate greenhouse gas pollution: “This is how science works. EPA is not required to re-prove the existence of the atom every time it approaches a scientific question.”

I couldn’t have said it better myself. As for government agencies, so, too, for journalists — the basic understanding of climate change and the impact of increasing greenhouse gases in the atmosphere is settled science. It doesn’t need to be re-explained, re-debated or questioned every time it comes up in our reporting.