Last month, President Trump issued a long-promised executive order dismantling President Obama’s restrictions on carbon pollution — part of his broader assault on Obama’s environmental legacy. Today, the People’s Climate March is happening in DC — and in sister rallies around the world. So it’s a good time to have another look at public opinion on climate change.

As I have written before (see here and here), there is a deep and abiding partisan divide in opinion on global warming. That divide has held steady for decades now, through shifting weather, political administrations, and cultural moods.

It is not strange that this partisan divide on climate should exist. America is deeply divided along partisan lines, and that is reflected in public opinion on almost every issue, political or otherwise.

What is strange is how much trouble climate hawks, scientists, and environmentalists have had accepting what is right in front of their faces. Millions of words have been written over the years attempting to plumb the socio-psychological depths of climate denialism — endless polls, studies, surveys, focus groups, A-B tests, and analyses seeking an explanation for the alleged mystery of how millions of people could reject well-established scientific conclusions.

But it is no mystery. Republicans deny climate change because they are Republicans and that’s what Republicans do.

The climate split is the partisan split

The analysts at Rhodium Group have found a nice visual way to illustrate the point. They started with data from the Yale Program on Climate Change Communication, which runs a big survey on climate change opinion every year (here’s 2016).

Yale surveys more than 18,000 adults and then runs various kinds of statistical regressions (more on methodology here) to derive county-level data on climate opinion. They then generate opinion maps on various climate-related topics. (I covered 2015’s here.)

Anyway, here’s the map of belief that humans are causing climate change:

Now here is a county-level map of 2016 presidential election voting results:

Notice any similarities? Yeah. They are very close to identical.

Rhodium puts a number on it: “86% of the variation across counties in respondent’s belief that ‘global warming is mostly caused by human activity’ is explained by voting preference.”

Another way of saying this: For practical purposes, most of what you need to know about people’s beliefs on climate change you can glean from their partisan affiliation. To a first approximation, most Democrats accept anthropogenic climate change, and most Republicans don’t.

That’s is a somewhat boring and frustrating conclusion, but it points to the only real path out of this mess.

Research shows that most people do not have particularly firm or coherent opinions on political issues. They don’t really think in terms of “issues” at all, not the way journalists and other politicos do. For the most part, they don’t read or watch political media. They are busy with lives and jobs and families and don’t have time to study policy disputes and form their own independent opinions.

Especially when it comes to something like climate change, which for most people is largely an abstraction, they are content to adopt the beliefs and tropes of their tribes, to go along with what their peers and trusted authorities say. This is true of Republicans and Democrats alike.

Republicans will accept that climate change is an urgent problem that warrants a policy response when leaders in conservative politics and media begin treating it that way. That is the only thing that can or will change the partisan divide on climate.

If you want to know what will bring conservative leaders and politicians around, the right level of analysis is not cognitive or psychological but political — it’s about money and power.

That is the simple and long since obvious truth behind the alleged mystery of climate denial.

Addendum: clean energy and pollution controls are more popular

It’s worth noting that environmental policies and solutions have not been completely caught up in the climate opinion maelstrom.

Yale also surveyed opinion on carbon controls on power plants (like the Clean Power Plan) and renewable portfolio standards (which require utilities to sell a certain amount of clean energy).

The results still distinctly show the effects of partisanship. “Voter preference in the 2016 Presidential election,” Rhodium writes, “explains 83% of the cross-county variation in both instances.”

But notice something else about these numbers: They are much higher. Carbon pollution standards are supported by an average of 69 percent of Americans. Renewable energy standards are supported by 66 percent. (This compares with 53 percent who accept human-caused climate change.)

The partisan divide shapes public opinion on solutions — clean air and clean energy — just like it does on climate change. But it has not dragged them down as far. They remain broadly popular, uniting Democrats and splitting Republicans. It is odd that ambitious young Democrats don’t make better use of them.