The Pope plans on delivering an encyclical on climate change this summer, and it has American conservatives freaking out. The Heartland Institute, a leading anti-environmental "think tank," has even dispatched a crack team of deniers to Rome to dissuade His Holiness.

Why the agita from the right? After all, similar statements of climate concern have been issued by virtually every major government, international development organization, and national science council in the world. It's not like the Pope is spilling the beans on a well-kept secret.

But as Heartland clearly recognizes, the Pope's statement carries unique significance for the simple reason that he has unquestioned moral authority for millions of people. He threatens to situate the fight against climate change as a deeply moral issue, a matter of God's work on earth. Once it is so situated, it will slowly and inexorably drag culture and politics along in its wake.

The right, which is entirely comfortable deploying moral arguments, understands this better than the mainstream, center-left environmental establishment. Large swaths of the center-left establishment (especially among the foundations that fund things) are besotted with dreams of technocracy and bipartisan civility — so much so that in 2009 Matt Yglesias pleaded with greens to "put the plodding moralism back in."

Especially among young greens, that technocratic attitude is on the wane, especially in the wake of the 2010 cap-and-trade defeat, a decisive failure for the top-down, technocratic approach. Nowadays, activists are trying to put the plodding moralism back in, particularly through the fossil fuel divestment movement, which calls on institutions to cease all investments in the fossil fuel sector.

Nobody thinks the divestment movement can hurt fossil fuel companies in any direct financial way, but that's not what it seeks to do. Rather, it seeks to put mainstream institutions on record defining climate mitigation as a moral imperative, to create social consensus that inaction is not neutral — it is immoral.

Public sentiment on climate is shallow — a moral campaign tries to change that

For years, majorities of the public have accepted climate change and favored action to address it, but those commitments have run an inch deep. Climate is very few people's top issue, or even top five; few vote based on it or contact their representatives about it. Public opinion on it tends to drift back and forth depending on the weather, or who happens to be president.

In short, the movement to address climate change has lacked intensity and depth. And that is what activists are now attempting to generate, both to grow the movement and to lend it mainstream legitimacy.

The right understands the power of moral appeals. The conservative minority that opposes any action on climate change is intensely invested, because to them, preventing new taxes or government programs is a moral issue of the first order.

Climate activists have woken to the need for intensity. Thus divestment, a direct and explicit effort to define the actions of fossil fuel companies as immoral — so immoral, in fact, that to invest in them is to take part in that immorality. What's revealing is not that divestment is drawing criticism from the right, which is predictable enough, but that it is causing discomfort and dissonance on the center left.

Many technocrats are uncomfortable making climate change a moral issue

See, for example, the 2013 statement from Harvard University president Drew Faust explaining why Harvard doesn't plan to divest from fossil fuels. I invite you to read it yourself. It's quite thoughtful; you might even find it convincing.

We should be very wary of steps intended to instrumentalize our endowment in ways that would appear to position the University as a political actor rather than an academic institution. ... The endowment is a resource, not an instrument to impel social or political change.

Now read it through again, imagining that instead of fossil fuel divestment, Faust is discussing divestment from the apartheid regime in South Africa in the 1980s and early '90s. All the same arguments apply, except ... they don't.

Why not? Because racial apartheid had become a moral issue, transcending the bounds of "normal politics" and institutional imperatives. By the time the apartheid divestment movement finished, there was no escaping it. "We don't get involved" was no longer an excuse. The choice was divestment or implicit and immoral support for apartheid.

(In fact, Harvard did make all the same arguments against apartheid divestment at the time, only conceding to full divestment after years of student activism and lobbying. Does anyone now see that concession as the wrong decision?)

It makes the center-left elite uncomfortable to think of climate change and fossil fuels this way. Have a look at this post from Harvard environmental policy professor Robert Stavins, supporting Faust's decision. He says:

The problem ... is that climate change is fundamentally a scientific, economic, and political challenge. Viewing it as a moral crusade, I fear, will only play into and exacerbate the terrible political polarization that is already paralyzing Washington ...

Put aside the head-smackingly naive notion that climate advocates can defuse polarization by retreating from moral language. What would it even mean for something to be a "scientific, economic, and political challenge" but not a moral issue? What science we heed, what kind of economy we want, what policies we pass — are these not moral decisions? The distinction makes no sense at all if read literally. It is best read, instead, as expressing a deeper instinct, the impulse among Very Serious People to stay inside the bounds of normal politics, to cling to rationalism in the face of passion and power.

In normal politics, we agree on broad goals and debate solutions based on their practicality and cost; we treat fossil fuel companies as partners in the shared quest to create a sustainable future; university endowments focus on funding universities and don't get involved in political issues. In a moral crisis, there are those seeking to prevent suffering and those working to perpetuate it.

Technocracy hasn't worked on climate change

The attempt to address climate change through normal politics has been going on for 30 years now. The issue was first brought to public consciousness by scientists, who assumed that the best way to address a threat like this was to bring it to the attention of legislators. (Oh, scientists.)

And for years, the issue was mostly the province of scientists, academics, think tankers, and Washington insiders, all of whom tend to be left-brained wonks, all of whom preferred to approach climate as a technical policy problem. Get the models right, determine the "social cost of carbon," apply the appropriate carbon taxes and border adjustments, and lo, the machine would right itself.

Again and again this idealistic, apolitical wonkery has been chewed to pieces by the political process, where climate change is not viewed as a technical problem, much less a crisis, but rather as a conventional matter of incentives. Fossil fuels and their allies are loud and spend lots of money. Scientists and wonks are poor and quiet. Fossil fuels are at the heart of the US conservative tribal worldview, whereas climate is seen by most of the middle and left as an "environmental issue." Most of the incentives point the same way.

Something, some added pressure, must be added to break the system out of its lethargy. Activists have decided that a large-scale social movement, with a clear moral call to arms at its center, is the ticket.

What a moral campaign against fossil fuels might achieve

Can climate action become a moral imperative? On that question, there is no fact of the matter, no answer knowable in advance. Moral imperatives are not things societies discover but things they create, by believing in them. If enough people believe that climate action is a moral imperative, then it is. Belief makes it so.

It is the possible implications and consequences of that belief that hold promise, particularly in regard to another hot topic the news lately, so-called "unburnable carbon." The idea is that if the world's governments get serious about preventing catastrophic climate change, then they are going to pass serious restrictions on carbon, and if they do that, then a large majority of current fossil fuel reserves — around 80 percent — will be placed off-limits. They would become "stranded assets," in the argot. That would massively, massively impact the valuation of fossil fuel companies in capital markets, putting their very survival at risk.

Is this a real vulnerability for fossil fuel companies? Well, risk, like morality, is in the eye of the beholders. It is a vulnerability if enough people believe it is — if enough people believe governments really are going to restrict carbon.

What might convince the big players in finance that that's going to happen, that restrictions on carbon are inevitable and ought to be factored into the market valuation of fossil fuel companies?

One thing that might convince them is major civic institutions like universities, churches, and unions formally declaring that climate change is a crisis, that perpetuating the system of fossil fuel dependence is not just unwise but immoral, and that they can no longer in good conscience allow their investments to be used for that purpose.

The new climate narrative

As of now, the climate movement has not proven powerful enough to push the world's governments into sufficient action. There are lots of reasons for that, but one is that many people see the choice as fossil fuels or pre-modernity. Whatever problems fossil fuels may have, they beat "shivering in the dark." As Faust says in her statement, everyone uses fossil fuels; they supply, currently, 87 percent of global energy consumption.

But the climate movement's message, despite back-to-the-land stereotypes still floating around, is not that humanity ought to return to a pastoral, pre-modern, low-energy lifestyle, or that the global poor ought to remain poor. It's that a better world is possible — clean, high-tech, prosperous, and just — and that fossil fuel companies are using their enormous legacy wealth and power to prevent the transition to that better world. Doing so is immoral, as is supporting the enterprise with investment dollars. It is that narrative behind which activists are seeking to brand fossil fuel companies as social pariahs.

The divestment movement is "only" symbolic, yes, but that woefully underplays the value of symbolism. Humans are tribal creatures. They take their cues from their peers, not from dispassionate surveys of the scientific evidence. It's called "social proof."

The framing of climate action as a moral imperative is not entirely new, of course. It has always existed, somewhat uneasily, alongside the technocratic impulse. But with fossil-fuel divestment, activists have turbocharged it.

Most activists lack social and economic power as individuals, but here they have found a way to leverage large institutions — which do have social and economic power — in the cause of providing social proof that fossil fuel investments are no longer socially acceptable. They, like the Pope, are now explicitly and effectively forcing people and institutions into a moral choice on climate. In doing so, they help to build the movement and signal that policy restrictions on carbon are inevitable. That could change important people's behavior, which is much more than symbolic.