Our relationship with fossil fuels is like a lot of dysfunctional romances.

It’s destructive, and we know it. But it seems so totally bound up with who we are, and how we live, that we find it desperately hard to imagine life without this partner. And so we stick with it, day in, day out. We do that even though we know we’ll get hurt.

And, like many a difficult relationship, it’s centered on one, agonizing question: Should I leave, or can they change?

AP Photo/George Brich Age of relative innocence.

In the energy world, the relationship breaking point is represented by the oil-divestment movement. It’s a campaign that found fervor on university campuses, starting around mid-2012.

Prior to then, campus activism on climate-change issues was for the most part confined to what could be achieved locally and, for students, tangibly—demanding greener buildings and bike paths, for example. Activist Bill McKibben, founder of the environmental group 350.org, sought to refocus the efforts on universities’ huge investment portfolios.

“The logic of divestment couldn’t be simpler: if it’s wrong to wreck the climate, it’s wrong to profit from that wreckage,” McKibben wrote in a 2013 article for Rolling Stone. (The magazine acted as media partner for a tour of universities he made to kickstart the movement.) Students started demanding that their places of study sell out of the fossil-fuel industry. By mid-2015, 220 universities and other institutions had committed to divesting from fossil fuels.

Reuters/Jonathan Ernst Moment of passion.

The principle of ethical investment—and also divestment—is also strong in religious organizations with sizable portfolios and in funds with sustainability or social-consciousness mandates. And now it has grown to include some of the world’s biggest investors. In 2014, the Rockefeller heirs announced they would divest their $50 billion oil fortune from fossil fuels. In February 2016, the 8,150 billion kroner ($935 billion) Norwegian government pension fund brought in new guidelines that exclude companies based on the prevalence of their business devoted to coal-based energy.

In less than six months’ time, the Norwegian fund—set up in 1990 as a repository for money made from the sale of Norway’s oil— had divested from 52 companies in which thermal coal made up more than 30% of income, with additional divestments to come. (It adopted similar rules for weapons and tobacco at the same time it began selling fossil-fuel interests.)

Divestment is a strong choice, bold and final—the “I’m leaving!” *slams door* of the investment world.

Some huge shareholders are carving out another path. McKibben refers to it as shareholder engagement. That translates to: “Let’s talk about this.”

We need to talk about carbon

Helen Wildsmith knows a lot about the soul-searching, nuanced discussions that feature in long-term relationships.

Wildsmith leads climate stewardship at the Church of England’s investment wing, which has £5.7 billion ($7.6 billion) in assets under management. She’s also an advisor to the Carbon Disclosure Project, which works for greater transparency from companies. It’s a form of engagement that puts faith in the ability of people, and businesses, to change.

The need for serious conversations with companies, to try and persuade them to act differently, came out of a realization about the interconnectedness of different sectors, she says. For example, it’s a relatively easy decision to divest holdings in coal. It’s the most polluting energy source and, US president Donald Trump notwithstanding, few believe in a long-term coal-powered future. But divesting left investors—like the French insurance giant AXA, which announced it would divest from thermal coal in May 2015—with other energy holdings in their portfolios, Wildsmith says, “and of course attention immediately goes to oil and gas.”

But blaming the energy producers arguably isn’t as effective as also including those that demand the commodity, like utilities, which are major users of coal and gas. Meanwhile, banks fund both sectors, implicating the whole of financial services. It’s too big a web for many investors realistically to distance themselves from everything it touches. That’s given rise to a different approach.

“You’re starting to see subtleties building in because people think, ‘Well I can’t divest from all of that.’ And given that we need oil and gas over the next decade or so, people are wanting to work with those companies while [they] work out what their post-Paris transition plan is…and stick with them when those transition plans look sensible,” Wildsmith says, referring to the 2015 meeting in Paris where leaders from nearly 200 countries set global climate goals.

Divestment by some investors has, in some cases, spawned engagement by others. Historically, big funds and asset owners have worked behind the scenes, Wildsmith says, but increasingly they’re less willing to keep discussions private, or settle for the word of corporations—especially for anything that feels like “greenwash.” They want to see detailed plans.

Wildsmith has been the Church of England fund’s chief “engager” with BP since 2011, and has seen success. Shareholder resolutions filed by Wildsmith and her colleagues led to both BP and Shell agreeing to report on their exposure to climate-change risks.

Not all energy companies have been as amenable. Tom DiNapoli, who as New York State comptroller makes decisions for his state’s $180 billion pension fund, co-filed a shareholder resolution to get US oil major Exxon to report on their exposure, as BP and Shell had done, while a separate filing sought more transparency at Chevron.

Exxon’s board advised shareholders to vote against the motion for greater transparency, and the company tried, unsuccessfully, to get the US Securities and Exchange Commission to strike the resolution from the ballot before it came to a vote in May 2016. The measure failed, as did the Chevron shareholder resolution.

The bigger oil majors—like Exxon have been difficult to move, DiNapoli admits, but the attempt is important. “I think on this one, because they’re such a big player and such a big name, we felt it was important to engage them in the process,” he says, heartened that the resolution was backed by 38% of shareholders—a large enough percentage, he says, that there’s reason to hope the company takes note.

In May 2017, they tried again. This time it passed, with 62.3% of the shareholder vote in favor.

These boots were made for walking

Where is the red line for these investors, though? At what point should a company’s behavior be taken to mean that it’s time to stop talking, and move on?

I ask McKibben when he thinks investors should resort to the divestment option.

“Now,” he says. “2016 [was] the hottest year we’ve ever measured. Time is not on our side.”

McKibben isn’t reflexively opposed to the idea of investor engagement in the general sense. “Most problems” with company behavior can be solved with changes to structure or choices, he says. But not the problem of fossil fuels. In “a few cases,” like the hydrocarbon industry, he argues, “the business model of the company at hand is not flawed; instead, it is the flaw.”

He cites specifics: “Exxon, for instance, has no real plan other than digging up more hydrocarbons; they spend billions a year on it, and nothing that any shareholder engagement will do can change that—until their political power is broken, that is, which is part of what divestment aims at.”

Exxon’s response? Divestment is ”a diversion from the search for solutions to the dual challenge of addressing climate change risks and meeting global economic needs,” a spokesman for the company told Quartz.

In between these two relatively extreme views are investors, controlling trillions of dollars of assets. Most of them are likely searching for more nuanced answers.

If they have diverse portfolios, their holdings will likely include an array of sectors with varying degrees of influence on the environment. In the energy sector alone they could be dealing with everything from coal and conventional crude to the lithium used in batteries, and palm oil used for biofuels. Applying uniform demands and deadlines is hard, and long, painstaking discussion is often needed.

Some of the companies they invest in will shape up. And eventually, those that don’t might wake up one morning to find a note on the table, propped between the coffee pot and the latest annual report: “We both know it wasn’t working. It’s over.”