Bill McKibben is an environmentalist and author, most recently of Falter: Has the Human Game Begun to Play Itself Out?

For three decades in American politics, climate change has been the issue that wasn’t. Even as the temperature steadily rose, and evidence mounted that it was human behavior—and human policies—that were driving this change, candidates mostly deflected. And it wasn’t hard: During the 2016 general election, no journalist even asked the presidential candidates a debate question on the topic.

But that’s not the case this time. Climate change matters for Democratic voters: A Monmouth University poll last month showed the issue as the second most important to Iowa caucus-goers after health care, and a CNN national poll found that 82 percent of Democratic respondents said it’s “very important” that their party’s nominee for president supports taking “aggressive action” to slow the effects of climate change, the highest support among several items on the progressive wish list. Most of the candidates seem convinced it’s a key weakness for Trump, and the front-runners have all embraced the issue. (The latest to weigh in, Beto O’Rourke, chose climate as the subject of his first comprehensive policy plan: a $5 trillion proposal for clean-energy infrastructure.) The question is not whether the candidates are going to talk about global warming, but how.


As the race takes shape, two key questions are materializing: What do climate-motivated voters really want? And how is the issue likely to change the race?

To review the sad history briefly: The high point of presidential climate campaigning to date probably came in 1988, when George H.W. Bush announced that he planned to “fight the greenhouse effect with the White House effect.” (He didn’t.) In the years that followed, candidates routinely avoided the issue. Al Gore strategically avoided it in 2000, and then, even in the wake of Gore’s magnificent Oscar-winning 2006 documentary, An Inconvenient Truth, Barack Obama barely mentioned it in his 2008 run, aside from a throwaway pledge that “the rise of the seas” would begin to slow in his administration and unfulfilled plans made in a campaign speech on energy independence to implement cap and trade and create 5 million “green jobs.” In 2012, it took Hurricane Sandy, in the final days of the campaign, to shake a few pro forma words out of Obama and Romney. Donald Trump owned the issue in 2016: It was hard for anyone to top his insistence that the whole thing was a “hoax manufactured by the Chinese.”

But if you look a little more closely, climate has been breaking through despite the candidates’ attempts to avoid it. Bernie Sanders began making a big issue of climate during his insurgent run for the Democratic nomination last time around. It was one of the most reliable applause lines in his stump speech, and in one face-off with Hillary Clinton (who also had comprehensive and useful climate plans), he declared it the most important issue of all. As with his "Medicare for All" proposal, that has helped pull the Democratic field leftward for 2020. Climate was edging its way into the presidential discussion, and now the edging is over.

In part, this is because climate has made such strong incursions into national politics outside the race. Last November, young people staged a sit-in at Nancy Pelosi’s office demanding a "Green New Deal"—turning a policy proposal into a national touchstone when Alexandria Ocasio-Cortez joined in. Fox and conservatives railed against the Green New Deal, but polling, at least among Democrats, has stayed strong, and so far the party’s candidates have mostly paid it homage: The standard response falls along the lines of “I support the concept.” Pete Buttigieg, as is his wont, framed it pretty well, saying, “It correctly situates this as a major national emergency. It identifies this as a problem whose destructive powers is comparable to a Great Depression or world war, except this time we see it coming. So shame on us if we don’t do something.”

However, even such strong endorsements likely won’t be enough for an increasingly confident climate movement; nor will status quo ante pledges like the recent House vote in favor of rejoining the Paris climate accords. Given the reality of the Republican Party’s grip on the White House and Senate, not to mention the accords’ limited ambition, that vote was a wishy-washy exercise in virtue signaling not much better than announcing you believe in climate science.



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When it comes to what activists are looking for, the most important thing is moving beyond symbolism to on-the-line commitments that can be cashed in after Inauguration Day. The group 350 Action, for which I serve as a board member, has the most comprehensive climate scorecard, tracking three key issues.

The first thing to watch as the race evolves is support for the Green New Deal—as an actual policy, not as a political slogan. Since the plan isn’t fully fleshed out, it’s hard to hold candidates completely accountable now, but the Sunrise Movement, the young people who launched the initiative, are holding 100 town halls across the country that began in April. Expect candidates to try to grab those crowds, and in the process commit themselves more fully to the emerging plan.

The second is what’s become known as “Keep It in the Ground”—a specific promise to stop new permits for drilling and mining on federal ground, and to apply a climate test to all new proposed infrastructure. A version was first introduced as a bill in the Senate by Sanders and Sen. Jeff Merkley in 2015, but it’s important as we head into 2020 because a president could accomplish much of it by executive fiat, without waiting for Congress to come on board. With building trade unions in opposition, it takes a certain nerve to support it; Elizabeth Warren’s powerful stance on this in recent weeks will likely draw many others along.

The third test is easiest: a simple pledge not to take money from the fossil fuel industry. After years of statistics showing the powerful links between oil money and oily votes, there’s simply no patience left for taking cash from the companies now facing lawsuits for repeatedly lying about global warming.

So on these measures, how are the candidates doing? At least five—Sanders, Warren, O’Rourke, Kirsten Gillibrand and self-proclaimed climate candidate Jay Inslee—have hit the trifecta so far (After lots and lots of questions on the subject, O’Rourke this week signed a pledge to stop taking fossil fuel money). A few have failed spectacularly: former Colorado Governor John Hickenlooper is known as “Frackenlooper” in environmental circles because (and you can look it up on YouTube) he once proved his fealty to the state’s oil barons by drinking a glass of fracking fluid. Most other candidates are still a little watery.

It’s early days, however, and environmental groups have mastered the art of bird-dogging candidates in Iowa and New Hampshire, waiting along rope lines to get the comments that quickly spread across the net. Expect new issues to emerge. Trump, for instance, recently offered a new approval designed to spur construction of the Keystone Pipeline. If it looks like TransCanada is anywhere near breaking ground on the project, Democrats will be expected to fight back hard, backing up thousands of activists who are pledged to conduct civil disobedience.



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Expect the issue to spill over into other areas too. As a powerful New Yorker piece recently made clear, climate change is causing much of the exodus from Central America that ends up on the southern border, and since the U.S. has poured more greenhouse gases into the atmosphere than any other nation, it’s hard to escape the conclusion that some of those children Trump stuck in cages were driven there by us. Just as Syria’s drought helped trigger the refugee crisis that reshaped European politics, Guatemala’s might do the equivalent here, and it’s hard to predict in which direction.

Increasingly, climate change is the classic intersectional issue, one where many types of injustice converge, the fight led by people who live on the front lines of devastation. Connecting climate with health, with jobs, with justice hasn’t watered down the issue: It’s made it a priority for many more Americans who can see how the crisis touches their everyday lives.

And not just the crisis, but also the opportunity it presents, which is why the economic discussion during the campaign is likely to turn in some measure on climate as well. The transition to renewable energy at scale is the most obvious big source for new jobs, and in one state after another, solar and wind entrepreneurs have begun to rival or surpass their fossil fuel counterparts as job creators. Even Trump’s commitment to the coal industry has been insufficient to turn the economic tide: Coal-fired power plants have closed more quickly in his first term than in both of Obama’s.

Environmentalists are pushing for a presidential debate sometime during primary season that focuses exclusively on climate change. If they get it, expect a chance for some to prove their mastery of climate wonkery. (Inslee really does know the issue inside and out.)

And there could be other surprises, too. Trump actually used to believe in climate action, signing on to calls for carbon cuts barely five years ago. He said recently that he might run on his environmental record — a silly idea, unless the oil industry decides it’s scared enough of ongoing litigation (and the Green New Deal) that it would accept a modest carbon tax, in which case Trump might be the guy they chose to push it forward. And if he did, the Democrats would be caught between wanting the right deal and wanting any deal.

For climate activists, as for all progressive groups, the Democratic primary offers a hard choice. We’re eager to make sure that the next president finally does something truly serious about climate change. But like all progressives, we’re terrified of another Trump term and worried just a tad about pushing too hard, about setting up the candidate for defeat by getting them too far out on a limb. It would all be easier if we hadn’t wasted the past 30 years, but that inaction has left us at a moment when physics demands enormous change. And so, in the end, we will push. On a planet where the poles are rapidly melting, what choice do we have?