We’ve all learned a good deal about epidemiology in the past few weeks. In particular, the notion that staying at home can break chains of transmission, and thereby interrupt the spread of the coronavirus, is now ingrained in the minds of anyone who hasn’t been watching Fox News exclusively. My favorite graphic description of that action looks like this. And, in places such as South Korea, there are signs that it’s begun to work.

Once you see something, you start seeing it everywhere. Over the weekend, I was reading a fine new book, “Citizen Outlaw,” about a New Haven gang leader turned gang-outreach officer who, by talking down revenge-minded young men, manages to interrupt the cycle of retaliation. “Jumping in at exactly the right time makes all the difference,” the author, Charles Barber, explains. Barber, who has written extensively on mental-health and criminal-justice issues, cites studies showing that, otherwise, a single death can lead to a cascade of violence. In an Illinois study, for instance, “a single incident that was linked through the victim’s social networks to 469 separate violent incidents.”

The coronavirus and gang violence are both examples of public-health problems where interrupting the spread of something, once you figure out how to do it, is fairly intuitive. But the logic holds, I think, for other realms, including the fight against climate change. The mental image of breaking chains of transmission helps me understand intellectually some of the work that activists have been doing in the past decade, and suggests strongly some paths to follow going forward.

About ten years ago—after the defeat of congressional efforts to tackle climate change by pricing carbon, through the Waxman-Markey bill—activists began working on a series of much smaller interventions. People in groups including 350.org (which I helped found) joined indigenous groups and farmers who were already fighting the Keystone XL pipeline, which was intended to carry tar-sands oil from Alberta to the Gulf Coast, and made it a national issue. They also began asking institutions to divest their stock holdings from fossil fuels.

Many pundits thought such approaches were futile. An opinion piece in the Washington Post said that the Keystone fight was “an irrational and insulting litmus test for seriousness about climate change” that “made the environmental movement look capricious and immature” because “the real, formidable task” was “transitioning the economy onto low- and no-emissions technology.” An allied group of doubters—the “that bus you took to the protest runs on gasoline!” critics—said that, instead, the emphasis should be on working to reduce people’s emissions.

In retrospect, it turns out that those actions were attempts to cut the chains of transmission that allowed the fossil-fuel industry to keep expanding. The Keystone fight was successful in stopping that pipeline, at least so far. (Barack Obama rejected the pipeline and, though Trump quickly reversed his ruling, the work has not been completed. This week, tribal groups are demanding the end to construction “man camps,” in light of the virus.) The delay has been very useful: it has meant eight hundred thousand barrels a day of the dirtiest oil on earth not flowing down through Nebraska. But by itself, obviously, stopping the pipeline wouldn’t turn the tide against climate change. The good news is that, as people watched that protest, they decided to fight everything else, too: now no fracking wells or coal mines or liquefied-natural-gas terminals get built without a fight. The most compelling of those battles—the standoff over the Dakota Access Pipeline at Standing Rock, the kayaktivist blockade of Shell’s Arctic drilling rigs in Seattle and Portland harbors—get lots of coverage, but around the globe every day similar fights are under way. They’ve slowed the growth of the fossil-fuels complex: the government of Alberta expected oil production in the tar sands to have quadrupled by this year, but, without pipelines to carry the crude, it has had to impose production restrictions.

Similarly, divestment began small. The first institution to divest, Unity College, in Maine, had a twelve-million-dollar endowment. Now funds worth more than twelve trillion dollars have divested from fossil fuels, and oil and coal companies credit that with making their expansion difficult; it’s a brake on their acceleration. This is not the same, of course, as solving the problem, any more than slowing the spread of coronavirus makes people healthy. COVID-19 could just miraculously vanish (President Trump’s predicted solution), but we’d still have an unhealthy America. There is a great deal of work to be done, on everything from health-care access to opioid addiction and nutrition. That kind of work is perhaps harder, and definitely different. It’s utterly necessary that there are people working on the Green New Deal—and, this week, on a green economic stimulus. And engineers and entrepreneurs need to continue to make solar power cheaper. Over time, these are the more important tasks than protest. But the success of that work depends on everyone else coming together in broad movements to break the political and economic power of the fossil-fuel industry.

This means that we should keep looking for pressure points and opening up gaps in the chain that keeps the planet-wrecking industry thriving. Recently, there has been a movement to get banks, asset managers, and insurance companies to stop steering cash to the carbon companies. And it’s beginning to work—financial institutions have started to limit their investments in coal-fired power, in Arctic drilling, and in the tar sands. None of this works overnight, or entirely: as with the coronavirus, relaxing vigilance means that transmission recurs. But it’s good to have a mental map of where we’re headed. If we can learn to slow the coronavirus microbe, we can learn to slow the carbon molecule.

A Guide to the Coronavirus