Back in 1998, a little-known climate scientist named Michael Mann and two colleagues published a paper [PDF] that sought to reconstruct the planet’s past temperatures going back half a millennium before the era of thermometers — thereby showing just how out of whack recent warming has been. The finding: Recent Northern Hemisphere temperatures had been “warmer than any other year since (at least) AD 1400.” The graph depicting this result looked rather like a hockey stick: After a long period of relatively minor temperature variations (the “shaft”), it showed a sharp mercury upswing during the last century or so (“the blade”).

The report moved quickly through climate science circles. Mann and a colleague soon lengthened the shaft [PDF] of the hockey stick back to the year 1000 AD — and then, in 2001, the U.N.’s Intergovernmental Panel on Climate Change prominently featured the hockey stick in its Third Assessment Report. Based on this evidence, the IPCC proclaimed that “the increase in temperature in the 20th century is likely to have been the largest of any century during the past 1,000 years.”

And then all hell broke loose.

Mann tells the full story of the hockey stick — and the myriad unsuccessful attacks on it — in his 2012 book The Hockey Stick and the Climate Wars: Dispatches From the Front Lines; Mann will appear at a Climate Desk Live event on May 15 to discuss this saga. But to summarize a very complex history of scientific and political skirmishes in a few paragraphs:

The hockey stick was repeatedly attacked, and so was Mann himself. Congress got involved, with demands for Mann’s data and other information, including a computer code used in his research. Then the National Academy of Sciences weighed in in 2006, vindicating the hockey stick as good science and noting:

The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on ice caps and the retreat of glaciers around the world.

It didn’t change the minds of the deniers, though — and soon Mann and his colleagues were drawn into the 2009 “Climategate” pseudo-scandal, which purported to reveal internal emails that (among other things) seemingly undermined the hockey stick. Only, they didn’t.

In the meantime, those wacky scientists kept doing what they do best — finding out what’s true. As Mann relates, over the years other researchers were able to test his work using “more extensive data sets, and more sophisticated methods. And the bottom line conclusion doesn’t change.” Thus the single hockey stick gradually became what Mann calls a “hockey team.” “If you look at all the different groups, there are literally about two dozen” hockey sticks now, he says.

Mother Jones’ Jaeah Lee traced the strange evolution of the hockey stick story in this video:

Indeed, two just-published studies support the hockey stick more powerfully than ever. One, just out in Nature Geoscience, featuring more than 80 authors, showed with extensive global data on past temperatures that the hockey stick’s shaft seems to extend back reliably for at least 1,400 years. Recently in Science, meanwhile, Shaun Marcott of Oregon State University and his colleagues extended the original hockey stick shaft back 11,000 years. “There’s now at least tentative evidence that the warming is unprecedented over the entire period of the Holocene, the entire period since the last ice age,” says Mann.

So what does it all mean? Well, here’s the millennial-scale irony: Climate deniers threw everything they had at the hockey stick. They focused immense resources on what they thought was the Achilles’ heel of global warming research — and even then, they couldn’t hobble it. (Though they certainly sowed plenty of doubt in the mind of the public.)

What’s more, even if they’d succeeded, in a scientific sense it wouldn’t have even mattered.

“Climate deniers like to make it seem like the entire weight of evidence for climate change rests on the hockey stick,” explains Mann. “And that’s not the case. We could get rid of all these reconstructions, and we could still know that climate change is a threat, and that we’re causing it.” The basic case for global warming caused by humans rests on basic physics — and basic thermometer readings from around the globe. The hockey stick, in contrast, is the result of a field of research called paleoclimatology (the study of past climates) that, while fascinating, only provides one thread of evidence among many for what we’re doing to the planet.

Meanwhile, the hockey stick’s blade doesn’t just stop rising of its own accord. It’s just going to go up, and up, and up, as the image above, combining the Marcott hockey stick with projections of where temperatures are headed by 2100, plainly shows.

When he shows that graph to audiences, says Mann, “I often hear an audible gasp.” In this sense, the hockey stick does indeed matter — for it dramatizes just how much human irresponsibility, in a relatively short period of time, can devastate the only home we have.

This story was produced as part of the Climate Desk collaboration.

On Feb. 17, more than 40,000 climate change activists — many of them quite young — rallied in Washington, D.C., to oppose the Keystone XL pipeline, which will transport dirty tar-sands oil from Canada across the heartland. The scornful response from media centrists was predictable. Joe Nocera of the New York Times, for one, quickly went on the attack. In a column titled “How Not to Fix Climate Change,” he wrote that the strategy of activists “who have made the Keystone pipeline their line in the sand is utterly boneheaded.”

Nocera, who accepts the science of climate change, made a string of familiar arguments: The tar sands will be exploited anyway, the total climate contribution of the oil that would be transported by Keystone XL is minimal, and so on. Perhaps inspired by Nocera-style thinking, a group of 17 Democratic senators would later cast a symbolic vote in favor of the pipeline, signaling that opposing industrial projects is not the brand of environmentalism that they, at least, have in mind.

The Keystone activists, not surprisingly, were livid. Not only did they challenge Nocera’s facts, they utterly rejected his claims as to the efficacy of their strategy: Opponents of the pipeline have often argued that it is vital to push the limits of the possible — in particular, to put unrelenting pressure on President Obama to lead on climate change. Van Jones, the onetime Obama clean-energy adviser and a close supporter of 350.org founder and Keystone protest leader Bill McKibben, has put it like this: “I think activism works … The lesbian, gay, bisexual, and transgender movement kept pushing on the question of marriage equality, and the president came out for marriage equality, which then had a positive effect on public opinion and helped that movement win at the ballot box and in a number of states, within months.”

This article is about the emotionally charged dispute between climate activists and environmental moderates, despite their common acceptance of the science of climate change. Why does this sort of rift exist on so many issues dividing the center from the left? And what can we actually say about which side is, you know, right?

Does Joe Nocera really have a sound basis for calling the pipeline opponents’ strategy boneheaded — or is that just his gut feeling as a centrist? Does Van Jones have any basis for claiming that activism works — or is it just his gut feeling as someone favorably disposed towards activism?

It’s high time we considered the science on these questions. There is, after all, considerable scholarly work on whether activists, by pushing the boundaries of what seems acceptable, create the conditions for progress or, instead, bring about backlashes that can complicate the jobs of sympathetic policymakers.

There’s also data that may shed light on why these rifts between “moderates” and “activists” are more the rule than the exception — across the ideological spectrum. “I can’t really think of any movement where there isn’t some internal dissent about goals and tactics,” says Carleton College political scientist Devashree Gupta, who studies social movements. The recurrence of this pattern on issues from civil rights to gun control to abortion suggests that there is something here that’s well worth understanding, preferably before the next rhetorical bloodbath around Keystone.

A chief benefit of this line of inquiry: It should prove duly humbling to activists and moderates alike — and thus might help to unite them.

From the outset, I think we can agree on one fundamental point: Over the past several years, driven by the failure of cap and trade and a worsening climate crisis, America’s environmental movement has become considerably more activist in nature — some might even say “radical.” Exhibit A is the successful attempt by 350.org inspirer-in-chief McKibben (who has written extensively about climate for Mother Jones) to create a grassroots protest movement rather than simply to work within the corridors of power.

“What Bill is doing is actually quite impressive — he’s the first one to create a social movement around climate change, and he’s done it by creating a common enemy, the oil industry, and a salient target, which is Keystone,” says Andrew Hoffman, a professor at the University of Michigan who studies environmental politics.

One crucial aspect of this shift is a growing reluctance by environmentalists to work hand in hand with big polluters. The latter was a central feature of the U.S. Climate Action Partnership, the industry-environmental collaboration that led an unsuccessful cap-and-trade push a few years back. Nowadays, the environmental movement is moving toward a more oppositional relationship with industry, as evidenced by its attempts to block a major industrial project (Keystone) and to get universities and cities to drop their investments in fossil fuel companies (another of McKibben’s goals).

The rival environmental factions are sometimes described as “dark greens” (the purists who want to force radical change) and “bright greens” (those who seek compromise and accept tradeoffs). There’s really little doubt that dark greens are on the ascendant. “He’s pulling the flank out,” Hoffman says of McKibben. “I do think he has a valuable role in creating a space where others can create a more moderate role.”

It’s also fair to say that McKibben — the charismatic journalist-turned-organizer — lies a good way to the political left. Its centrist biases notwithstanding, a recent paper by American University communications professor Matthew Nisbet does capture McKibben’s “romantic” ideology: Like most people, he’s unhappy about environmental degradation, but he also seems opposed, in a significant sense, to the economic growth engine that drives it. He believes in living smaller, in going back to nature, in consuming less — not a position many politicians would be willing to espouse. (Indeed, President Obama’s comments about climate change often contain an explicit rejection of the idea that environmental and economic progress are mutually exclusive.)

So environmentalists are moving left and becoming more activist in response to political gridlock and scary planetary rumblings. Then along come the moderates, unleashing flurries of what Grist’s David Roberts calls “hippie punching” under the guise of being more rational and reasoned than those they are criticizing. For example, Nisbet writes: “McKibben’s line-in-the-sand opposition to the Keystone XL oil pipeline, his skepticism of technology, and his romantic vision of a future consisting of small-scale, agrarian communities reflects his own values and priorities, rather than a pragmatic set of choices designed to effectively and realistically address the problem of climate change.”

You can see how an activist might find this just a tad irritating. For what is Nisbet’s statement if not a reflection of his own values and priorities? Words like “pragmatic” and “realistic” give away the game.

The truth is, ​there is every reason to suspect that both groups are driven by divergent emotions, passions, and personality dispositions — or at least, so says the body of research (admittedly, still in an early phase) that exists on the matter.

We live in an era in which politics seems less and less comprehensible without turning to psychology. In particular, there is a growing realization that today’s Democrats and Republicans simply don’t understand one another, and are trapped in a kind of unending political Mars and Venus saga due to their divergent personalities, psychologies, and emotionally rooted moral systems.

Yet anyone who has hung around the environmental movement long enough may have noticed an eerily similar version of this phenomenon in the divide between moderates and activists. And there are at least some researchers out there helping us to make sense of this divide.

First, let’s consider the personalities of so-called moderates: Research by Yale political scientist Alan Gerber and his colleagues suggests that people who score high on the personality trait “openness to experience” are not only more likely to lean liberal (a long-standing finding in political psychology) but, more surprisingly, are more likely to insist on remaining politically unaffiliated — in which case they tend to identify themselves as centrist, moderate, or independent.

It appears that openness to experience, beyond its literal meaning, signals a desire to stand out from the crowd. These people are not joiners, or team players. So it would not be out of character for them to criticize people on their side of the aisle in order to distinguish themselves from their presumed allies. In this camp, we might expect to see plenty of instinctive contrarians, like the pundits and journalists who enjoy declaring a pox on both houses.

So, are moderates like Nocera really more rational or reasonable than activists? Gerber’s results suggest that there may simply be a “moderate” personality for whom this contrarian hippie-punching instinct simply feels right.

Beyond the personality studies, there is a growing body of research on the deep-seated emotions that underlie our personal politics. Dubbed “moral foundations theory,” it consists largely of work done by New York University psychologist Jonathan Haidt, Jesse Graham of the University of Southern California, and their colleagues and collaborators. Their approach is to measure the five (sometimes six) moral “foundations” that seem to drive our responses. (They are: “care/harm,” “fairness/cheating,” “loyalty/betrayal,” “authority/subversion,” and “sanctity/degradation.”) In short, they have been able to demonstrate that people’s views on right and wrong, and the intensity with which we respond to moral and political situations, have more to do with our gut instincts than rational consideration of the facts before us; our moral “reasoning” is actually a form of post hoc rationalization.

What can moral-foundations theory tell us about the chasm between environmental moderates and activists? Ravi Iyer of USC, a collaborator of Haidt and Graham, agreed to run some data for me, based on a sample of 15,552 individuals who responded to the researchers’ moral-foundations questionnaire, as well as a separate questionnaire that included a question about environmental attitudes.

The result was revealing: People who had professed that it is important to “protect the environment” not only tended to be liberal (no surprise), but they also exhibited a considerably higher sensitivity to moral considerations about “care/harm.” In other words, when they weighed the right and wrong of a given situation, these respondents were more concerned than their fellow citizens about “whether or not someone suffered emotionally” and “whether or not someone cared for someone weak or vulnerable.”

Iyer suggests that environmentalists’ care/harm considerations extend far beyond the immediate and the local — they also apply to distant peoples, animals, habitats, and future generations. (This finding is consistent with a recent study on the “moral roots” of environmentalism by Matthew Feinberg of Stanford and Robb Willer of the University of California-Berkeley.)

Iyer then ran a second analysis. He compared the moral responses of liberals who scored highest in their desire to protect the environment with those of liberals who scored lower, yet still said they cared about the environment. This analysis, a proxy for the differences between the environmental purists and moderates, turned up relatively small but still noteworthy differences. The purists, or activists, tended to be more sensitive to three of the five moral foundations: “care/harm,” “fairness/cheating,” and “sanctity/degradation.” This suggests that if you want to engage an environmentalist activist on an emotional level, you should try a moralizing narrative: A corporation with too much power (unfair) is causing devastating damage (care/harm), defiling (sanctity/degradation) the environment and jeopardizing the planet for future generations (care/harm). Sound familiar?

Perhaps most revealing, though, was the center-vs.-left difference in the realm of “sanctity/degradation,” a moral sensibility associated with disgust that is usually much stronger on the political right than on the left. It is measured by asking people how much they factor in “whether or not someone violated standards of purity and decency” and “whether or not someone did something disgusting” when deciding what is moral or immoral. Iyer’s analysis suggests that environmental activists, more so than the moderates, associate the environment with purity and feel revulsion when it is defiled. This may leave them viscerally offended by perceived abuses of the sanctity of nature — and less willing to compromise on their ideals.

The moderates, who are less driven by pure “care/harm” concerns, may tend to be less emotional about preserving the environment in a pristine state, and are thus more willing to endorse trade-offs. “The more moderate you are, the less extreme you are in any of the moral foundational domains,” says Stanford’s Matthew Feinberg. “So you probably are more utilitarian or consequentialist in the way you perceive the world.”

Does this mean that moderates are more rational? Insofar as they are less moralistic, they have something of a claim. But it is offset by their tendency towards knee-jerk centrism, which can be just another reflex.

The bottom line is that the activists and moderates respond and feel differently when faced with the same moral and political situation. And both factions are likely biased by their initial, emotional responses. Thus, a moderate can be just as reactionary as an activist — especially if he or she never moves beyond that first instinct and simply splits the difference between the opposing sides in every situation.

Let us now return to the Keystone debate. If you’ll recall, the moderates’ instincts tell them that activists create backlash that interferes with the movement’s wider goals, whereas the activists believe their protests create space for, at minimum, the achievement of more moderate goals. So which side is correct?

To answer that question, we have to turn to a different body of research: the study of “radical flank effects” in social movements. Perhaps the most seminal work on the matter was Black Radicals and the Civil Rights Mainstream, 1954-1970, a book published in 1988 by Herbert Haines, a scholar at the State University of New York-Cortland. Haines argued, provocatively, that radical groups like the Black Panthers and individuals like Malcolm X actually helped make space for a series of moderate successes (led by Martin Luther King Jr.) that culminated in the landmark 1964 Civil Rights Act.

Haines called this a “positive radical flank effect” because it led to a beneficial outcome for civil rights. But he also raised the possibility of “negative radical flank effects” — indeed, a delayed civil rights backlash had kicked in by the early 1970s. But overall, he argued, the presence of the radicals and their growing prominence helped create favorable conditions for the moderates to push important legislation.

The radical flank concept now “has a lot of credibility among social-movement scholars,” says Riley Dunlap, a sociologist at Oklahoma State University who studies climate change (and the people who claim it isn’t real). The concept has since been applied to political movements and moments ranging from women’s rights to the New Deal.

Some of Haines’ observations sound entirely relevant to today’s environmental moment. For instance: “Radicals specialize in generating crises which elites must deal with” — Keystone anyone? — “while moderates specialize in offering relatively unthreatening avenues of escape.” In other words, it’s a symbiotic relationship: The moderates are more attractive for the power brokers to negotiate with, Haines writes, “but all the more so when more militant activists are applying pressure.”

The sad irony here is that the activists don’t get what they want. In the end, they merely get to help out the moderates. But that’s the nature of the positive radical flank effect.

For this article, I asked several sociologists and specialists on movements — Haines included — how one might apply the radical flank theory to the current environmental movement. Short answer: It’s tough without the benefit of hindsight. “It’s easy to do when you look over the course of history, but when it’s right in the moment, it’s really complex,” explains Jules Boykoff, a specialist on social movements at Pacific University in Oregon.

First, it is important to acknowledge, as Haines did, that the definition of “radical” hinges entirely on what society considers mainstream — and that’s a moving target. The tactics of radicals vary greatly, too — in this context, the peaceful anti-Keystone movement hardly counts as extreme.

But certain scholarly considerations may prove illuminating. For instance, one of the critical factors in determining whether a radical flank effect will be positive or negative is the way moderates and activists relate to one another. “How clearly are the moderates and radicals differentiating themselves?” asks Carleton College’s Devashree Gupta. This, as Gupta notes, shapes media coverage and the thinking of politicians and policymakers who may be calculating whether helping the moderates will ease the headaches the radicals create for them.

It is noteworthy that as the Keystone XL pipeline protests have heated up, environmental organizations have not differentiated themselves clearly. Indeed, the leaders of typically moderate groups such as the Environmental Defense Fund and the Natural Resources Defense Council wrote a letter to President Obama in 2011 noting that “there is not an inch of daylight between our policy position on the Keystone Pipeline and those of the very civil protesters being arrested daily outside the White House.”

A second major consideration involves policy momentum. Here, the question is whether all sides agree that change is coming anyway. If so, a positive radical flank effect is more likely, as the status quo comes to envelop and embrace moderates (and spurn radicals). “For a positive effect to happen,” Haines explains, “what you kind of have to have is things moving in the right direction politically. So around environmentalism, it would have to be that policy is already moving in a pro-environmentalist direction, like civil rights was, and the radicals come along and give it a boost.”

Are things moving that way? That’s incredibly difficult to discern at the moment. Climate progress is clearly in congressional limbo. But culturally, you could say that there is indeed momentum as the public awakens to the reality of increasingly extreme weather, and even the Wall Street Journal is publishing op-eds supporting a carbon tax. There is also positive momentum in the sense that Obama clearly wants to do something for his environmental legacy, and there is still much he can do without cooperation from Congress.

Finally, any radical-flank analysis must consider the possibility of backlash. In a sense, that backlash has already happened, as the political right has taken up Keystone XL as a case study in environmentalists wanting to kill jobs. Haines cautions: “If you’ve got a radical flank and a very polarized environment, where there’s no real concept or impulse to compromise on the other side, then not only is more-militant stuff less likely to encourage progress, but it can become a weapon that the other side uses.”

In other words, the jury is still out on whether the Keystone protests will encourage positive action on climate — so it’s awfully premature to be calling the strategy “boneheaded.” Mobilizing thousands of people, drawing massive media attention, perhaps redefining environmentalism — these are all actions that, even if they do produce some backlash, will assuredly have myriad other effects that are difficult to foresee.

But the protesters might also take a gut check from this analysis: Their success is far from certain. And most galling, from the vantage point of history, their “success” may well be defined by their failure on the specific issue they care most about. It is not hard to imagine, for instance, an outcome that would be the very definition of a positive radical flank effect: Obama approves Keystone and simultaneously announces a number of initiatives long desired by centrist environmental organizations. Chief among them: new steps by the Environmental Protection Agency to regulate greenhouse gas emissions from existing power plants.

The activists would be bitterly disappointed, of course, but progress would be real and tangible. In this context, would Van Jones be wrong in saying that “activism works”?

To sum things up, we’ve seen that there is likely a deep seated, emotional and dispositional reason why some people wind up as activists and others as moderates. Perhaps the rift between the Noceras and the McKibbens of the world will make more sense — and even, perhaps, be diminished — if we can all accept the fact that enviros on both sides of the Keystone protests are feeling their way to their opinions.

Second, the study of social movements suggests that both outcomes — progress and backlash — can occur simultaneously, and the activists might well win by losing (or, if you prefer, lose by winning). Given all of the complexities, calling the mobilization of thousands of people around climate action “boneheaded” is, well, just that.

In the final analysis, it’s hard not to admire what McKibben and his supporters have pulled off. We don’t yet know which way the radical flank effect will go, but until fairly recently, there wasn’t even a flank to discuss. “The reality is that we’ve had no radicals so far, until Bill McKibben,” says Oklahoma State’s Riley Dunlap. McKibben has thrown the switch, and now the gears are turning, to uncertain end. [Editor's note: McKibben serves on Grist's board of directors.]

As we wait for the outcome, there’s a lesson here for the moderates: un-jerk those knees. For moderates’ actions matter, too, and their choices may have historic consequences. “Whether it’s a positive or negative flank effect, we decide that,” says Jules Boykoff. “If you diss somebody, dismiss them, use them for your short-term gain, you might sacrifice that group on the altar of missing what you actually want to happen.”

If the “bright greens” want to be known for nuanced views, sophistication, and willingness to endorse complexity and tradeoffs, then let them begin with this simple acknowledgement: Determining the historical impact of a movement like this one is anything but simple.

This story was produced as part of the Climate Desk collaboration.

On Feb. 17, more than 40,000 people rallied in Washington, D.C., to convince the president to reject the Keystone XL, a proposed 875-mile pipeline running from the Canadian border into Nebraska and slated to transport oil from tar sands (which is 17 percent more greenhouse-gas intensive than standard crude oil). The crowds outside the White House provided overwhelming proof that opposing Keystone has mobilized a new and powerful grassroots constituency.

But in the U.S. Senate, the mood was different. In a non-binding vote, 62 senators — including 17 pro-Keystone Democrats — voted to approve the pipeline. Just 37 senators voted against it. In fact, the amendment was co-sponsored by four Democrats, including Max Baucus of Montana and Heidi Heitkamp of North Dakota.

So are activists’ efforts all in vain? What will happen to the environmental movement if President Obama ultimately lets Keystone go forward?

And more broadly: What does this say about the best strategy for fighting climate change? Does compromise, horse-trading, and winning industry allies ultimately work best — or do you have to push the limits of the possible? You’re invited to the next Climate Desk Live event — hosted by myself — for a debate and discussion between some of the leading voices on this issue:

May Boeve, executive director and co-founder, 350.org.

David Roberts, Grist writer, who has been covering Keystone regularly and recently wrote about the “Virtues of Being Unreasonable on Keystone.”

Michael Levi, director of the program on Energy Security and Climate Change at the Council on Foreign Relations, and author of the new book The Power Surge: Energy, Opportunity, and the Battle For America’s Future, where he writes that combating climate change will require “doing deals [with those] who want to expand production of oil and gas.”

Michael Grunwald, senior national correspondent for Time magazine, author of The New New Deal: The Hidden Story of Change in the Obama Era, who recently declared that on Keystone, “I’m with the Tree Huggers!“

Join us for a Climate Desk Live event focused on the Keystone XL: Thursday, April 18, 2013, 6:30 p.m. at the University of California Washington Center, 1608 Rhode Island Ave NW, Washington, D.C. 20036. To attend, please RSVP to cdl@climatedesk.org.

This story was produced by Mother Jones as part of the Climate Desk collaboration.

George R.R. Martin’s wildly popular Game of Thrones saga — whose third season just launched on HBO — is, on the broadest level, a story driven by climatic change. “Winter is coming,” warn the ill-fated Starks, a family of northern nobles who help guard the realm from the frozen beyond. In Martin’s world, winters and summers vary in length and can for last years or even a generation — and as the books advance, a devastating winter begins to descend, forcing southward migrations and an intense test of mettle to see who can literally stand against the cold.

Back on Planet Earth, our own weather has felt distinctly Game of Thrones-like lately — depending heavily, of course, upon where you live. But if you’re in the northeastern U.S., 2012 felt like a long summer, with scarce any winter at all — whereas early 2013 featured a snowy winter that has felt like it won’t end (though it finally does now seem to be letting up). See here for a graphic of March temperature anomalies in 2012 and 2013, courtesy of Climate Central, proving this perception isn’t merely subjective:

The U.K. — a kind of homeland for Game of Thrones, in that the books are inspired by England’s historic “Wars of the Roses,” and the gigantic ice wall in the north of the fictional Westeros is modeled on Hadrian’s Wall, built by the Roman emperor to protect against tribes of Britons — is also undergoing a staggering winter this year. A recent Daily Mail report features disturbing pictures and video of sheep frozen to death in giant snow drifts, noting that the current freeze is threatening to persist throughout April.

So what’s going on here? Could climate change actually give us a Game of Thrones world with longer, or at least more variable, winters and summers? On an admittedly much more modest scale — we’re working with mere physics here, not a recurring meteorological conflagration between good (heat) and evil (cold) — the answer may be yes.

One key factor behind the U.K.’s and East Coast’s supercharged winter of 2013 is the odd behavior of the jet stream, the high-level river of air that meanders from west to east in the mid-latitudes of the northern hemisphere. Jennifer Francis, a climate scientist at Rutgers University, explains that climate change is weakening the jet stream through an unexpected mechanism — the dramatic melting of ice in the Arctic. And this, in turn, is leading to more fixed weather patterns — whether hot or, alternatively, intensely cold — across the globe.

“What’s been happening is this big trough parked over Eastern U.S., and also over western Europe,” says Francis of the current conditions. “And in both cases, because the jet stream has been in a very wavy pattern, these troughs have been very slow to move, basically parked most of the time in the same spot.”

Francis’s research has garnered increasing attention of late, as planetary weather seems to have gone increasingly haywire. Here’s how her theory works (for a scientific lecture with massively more details, see here).

As the Arctic grows warmer, and does so at a much more rapid clip than the mid-latitudes, this lessens the relative temperature difference between areas to the north and south of the jet stream. And that slows it down: The jet stream is literally like a river of air, which flows “downhill” from regions of denser, warmer air to regions of less dense, colder air. But if there’s less of a temperature gradient from north and south, the jet stream won’t flow as rapidly.

When that happens, says Francis, things get “stuck.” “When the jet stream is weaker, it is more easily thwarted from its path,” she says. “And it tends to meander more.” This can leave in place, for longer, a given set of weather conditions — whether unusually snowy or, alternatively, unusually warm.

Indeed, Francis explains that the mechanism is the same one as what we saw last year in the U.S., when things seemed abnormally warm, rather than abnormally cold.  “You can look back to last year, and remember that we were basking in recor-breaking heat,” she notes. “But it’s the same reason.” Once again, the jet stream was “stuck” — only, last year, that left the highs and lows in different places.

Of course, the jet stream isn’t the only factor helping to deliver more intense winters. There’s also more water vapor in the atmosphere as it heats, and that means that when you have a snowstorm, it can dump more precipitation. So if you have wintry weather patterns stuck in a given place, and more water vapor in the atmosphere — well. Winter is coming, says the forecast.

I asked Francis about Game of Thrones, and she confessed she doesn’t watch it. But as I explained the basic scenario, she commented: “There will always be a summer and a winter. But it could be that the transition seasons, the springs and the falls, will not be as gradual, there might be a tendency to go from a pretty chilly situation right into a very warm situation.” And, as usual, human civilization wasn’t built for any of this. Our buildings, our cities, our rhythms of ordinary life: They’re kind of like those crumbling, unmanned towers along the Wall in Game of Thrones. And our climate scientists? They’re kind of like the Starks and the Night’s Watch: The only ones who can see the danger that’s coming, but amid all the petty politics, they’re being totally ignored.

This story was produced as part of the Climate Desk collaboration.

Last week, a much discussed new paper in the journal Nature seemed to suggest to some that we needn’t worry too much about the melting of Greenland, the mile-thick mass of ice at the top of the globe. The research found that the Greenland ice sheet seems to have survived a previous warm period in Earth’s history — the Eemian period, some 126,000 years ago — without vanishing (although it did melt considerably).

But Ohio State glaciologist Jason Box isn’t buying it.

At Monday’s Climate Desk Live briefing in Washington, D.C., Box, who has visited Greenland 23 times to track its changing climate, explained that we’ve already pushed atmospheric carbon dioxide 40 percent beyond Eemian levels. What’s more, levels of atmospheric methane are a dramatic 240 percent higher — both with no signs of stopping. “There is no analogue for that in the ice record,” said Box.

And that’s not all. The present mass-scale human burning of trees and vegetation for clearing land and building fires, plus our pumping of aerosols into the atmosphere from human pollution, weren’t happening during the Eemian. These human activities are darkening Greenland’s icy surface, and weakening its ability to bounce incoming sunlight back away from the planet. Instead, more light is absorbed, leading to more melting, in a classic feedback process that is hard to slow down.

“These giants are awake,” said Box of Greenland’s rumbling glaciers, “and they seem to have a bit of a hangover.”

To make matters worse, there’s also Antarctica, the other great planetary ice sheet, with 10 times as much total water as Greenland — all of which could someday be translated into rising sea level. That includes the West Antarctic ice sheet, which is marine- rather than land-based, making it highly vulnerable to melting.

While Greenland is currently contributing twice as much water to sea-level rise as Antarctica, the situation could change in the future. According to Box, it’s kind of as though we’re in a situation of “ice sheet roulette” right now, wondering which one of the big ones will go first.

Box also provided a large-scale perspective on how much sea-level rise humanity has already probably set in motion from the burning of fossil fuels. The answer is staggering: 69 feet, including water from both Greenland and Antarctica, as well as other glaciers based on land from around the world.

Scientists like Box aren’t sure precisely when, or how fast, all that water will flow into the seas. They only know that in past periods of Earth’s history, levels of atmospheric greenhouse gases and sea levels have followed one another closely [PDF], allowing an inference about where sea level is headed as it, in effect, catches up with the greenhouse gases we’ve unleashed. To be sure, the process will play out over vast time periods — but it has already begun, and sea level is starting to show a curve upward that looks a lot like … well, the semi-notorious “hockey stick.”

So what can we do? For Box, any bit of policy helps. “The more we can cool climate, the slower Greenland’s loss will be,” he explained. Cutting greenhouse gases slows the planet’s heating, and with it, the pace of ice sheet losses.

In the meantime, to better understand where we’re headed, Box has launched a scientific project called “Dark Snow,” which seeks to crowdfund a Greenland expedition to help determine just how much our darkening of the great ice sheet in this unprecedented “Anthropocene” era will push us well beyond Eemian territory. The video for that project is below. If the remote, dangerous science of ice sheets intrigues you enough (or scares you enough), then you definitely will want this research to succeed:

This story was produced as part of the Climate Desk collaboration.

Jason Box speaks the language of Manhattans. Not the drink — the measuring unit.

As an expert on Greenland who has traveled 23 times to the massive, mile-thick northern ice sheet, Box has shown an uncanny ability to predict major melts and breakoffs of Manhattan-sized ice chunks. A few years back, he foretold the release of a “4x Manhattans” piece of ice from Greenland’s Petermann Glacier, one so big that once afloat it was dubbed an “ice island.” In a scientific paper [PDF] published in February of 2012, Box further predicted “100% melt area over the ice sheet” within another decade of global warming. As it happened, the ice sheet’s surface almost completely melted just a month later in July — an event that, in Box’s words, “signals the beginning of the end for the ice sheet.”

Box, who will speak at next week’s Climate Desk Live briefing in Washington, D.C., pulls no punches when it comes to attributing all of this to humans and their fossil fuels. “Those who claim it’s all cycles just don’t understand that humans are driving the cycle right now, and for the foreseeable future,” he says. And the coastal consequences of allowing Greenland to continue its melting — and pour 23 feet worth of sea level into the ocean over the coming centuries — are just staggering. “If you’re the mayor of Hamburg, or Shanghai, or Philadelphia, I think it’s in your job description that you think forward a century,” says Box. “They’re completely inundated by the year 2200.”

Unless, that is, something big changes — something big enough to start Greenland cooling, shifting its “mass balance” from ice loss to ice gain once again. But that would require us to reverse global climate change, in an ever-dwindling time frame for doing so.

Currently based at the Byrd Polar Research Center at Ohio State — with a joint appointment at the Geological Survey of Denmark and Greenland — Box got his research start while an undergraduate at the University of Colorado-Boulder. As a senior, he traveled north with the Swiss glaciologist Konrad Steffen. In subsequent years, as his scientific career developed, Box increasingly began to think outside of … his last name. Rather than waiting on funding agencies, he teamed up with Greenpeace on a series of expeditions to document, and also dramatize, the ice sheet’s melting. He also began to set up time-lapse cameras to observe the ice as it declines, something captured in the new documentary Chasing Ice, which features Box’s work.

Today, Box is trying to understand the feedback loops that may be driving a melting of Greenland that is much faster and more dramatic than many scientists expected. Take, for instance, melting on the ice’s sheet surface: Warmer or melting ice (or just plain meltwater) absorbs more sunlight than does healthy, cold ice. So as warmer temperatures melt the ice, the ice sheet absorbs more solar heat — melting even more. Another example: As Greenland melts, the massive ice sheet, more than two miles above sea level at its highest point, slumps in altitude. When that happens, more of the ice sheet is bathed in the warmer atmospheric temperatures that are found at lower elevations. So — you guessed it — it melts more.

But Box is most intrigued by one of the processes occurring atop the ice sheet, on its surface. Last summer, wildfires torched large parts of the U.S. West, and especially Box’s home state of Colorado. The soot from the fires traveled as far north as the Greenland ice sheet and, once deposited on the ice, these dark particles absorbed additional sunlight. Compounding this effect are the Arctic microbes that live off of impurities from soot — living longer as the ice warms, and releasing dark pigments to protect themselves from the sunlight.

“I’m sitting in LaGuardia on my way to Greenland, people riveted to the TV with news about fire across the U.S.,” Box remembers. “It was really dramatic, but I’m like, ‘Hold on, we need to really measure the soot.’” Thus was born the Dark Snow project, in which Box and colleagues are trying to crowdfund an expedition to sample the ice at high elevations and determine just how much soot from global wildfires and pollution is amplifying Greenland’s melting.

The upshot of what they know so far is that Greenland is not only melting — it may be melting faster than anyone expected, including most scientists. And what’s more, we may be blowing past a point of irreversibility, where the world commits, irrevocably, to a level of sea-level rise that, as it unfolds over the coming centuries, would devastate many coastal megacities.

Just consider one striking statistic from Box: The summer melt from Greenland in 2012 alone added a millimeter to the global sea level. And not only is that millimeter felt around the globe, but it is felt in specific places. For instance, it rode atop the wall of water that superstorm Sandy pushed inland at New York and New Jersey.

And that’s just a tiny fraction of what’s to come. One recent scientific prediction suggested that 1.6 degrees C (just under 3 degrees F) of temperature rise above pre-industrial levels might be enough to lock in Greenland’s complete melting. Greenland temperatures in summer have already risen a full degree C since the year 2000, and if the soot-related and biological feedbacks that are Box’s current focus turn out to be big enough, the 1.6-degree threshold might also be too conservative.

In other words, Box’s boots-on-the-ground perspective on Greenland suggests that the models might be undershooting things — and all that water may be coming faster still.

In his inaugural address, President Obama put a strong focus on the issue of climate change, citing the “devastating impact of raging fires, and crippling drought, and more powerful storms.” But all of this pales in comparison to a global ocean containing what used to be Greenland. And that, Box says, should serve as a major wake-up call, since “there’s no doubt that if climate continued like in 2012, Greenland’s gone.”

This story was produced as part of the Climate Desk collaboration.

Everybody who’s written or blogged about climate change on a prominent website (or, even worse, spoken about it on YouTube) knows the drill. Shortly after you post, the menagerie of trolls arrives. They’re predominantly climate deniers, and they start in immediately arguing over the content and attacking the science — sometimes by slinging insults and even occasional obscenities. To cite a recent example:

What part of “we haven’t warmed any in 16 years” don’t you understand? Heh. “Cherry-picking” as defined by you alarmists: any time period selected containing data that refutes your hysterical hypothesis. Can be any length of time from 4 billion years to one hour. Fuck off, little man!

It was reasonably obvious already that these folks were doing nothing good for the public’s understanding of the science of climate change (to say nothing of their own comprehension). But now there’s actual evidence to back this idea up.

Van Jones is a leading environmental and human rights advocate, President Obama’s former “green jobs” special adviser, a CNN contributor, and the New York Times bestselling author of The Green Collar Economy and Rebuild the Dream. Chris Mooney spoke with him by phone as part of our ongoing coverage of how Obama can tackle the climate issue — and lead — in his second term.

Q. Obama and global warming — decode his signals for us. Is he really going to take the lead here in the next four years, and prioritize this issue?

A. I think it’s not clear sometimes how America is prioritizing the issue. Four years ago, both presidential candidates, McCain and Obama, ran as climate champions. The only thing that they agreed on was that global warming was real, caused by humans, could be fixed by cap-and-trade, and that that would lead to jobs. Four years ago, that was common ground, and the only common ground. And four years ago, people were still impacted by Al Gore’s film, An Inconvenient Truth.

Well, all of the horrible things that were shown in Al Gore’s film in 2007, you can see on the Weather Channel in 2012. And yet you don’t see people marching down the street, even in the wake of Sandy, even in the face of the drought, demanding change. So I think that’s a factor in Washington, D.C., not being as vocal or as visible.

Now that said, I think that’s starting to change, and I think this president is going to have to deal both with the worsening science, and the returning public will to act. And I credit Bill McKibben and 350.org for coming on so strong since the election was over, and also the shock of Hurricane Sandy and its aftermath, for I think creating a new moment for climate solutions to take center stage.

Q. What would real climate leadership look like? You gave President Obama a “B or B-minus” on the environment in his first term. What would he have to do to earn an “A” in the second one?

A. An “A” would be a major energy and climate bill as a centerpiece of his legacy. He obviously has to deal with the economy and the budget issues that the Tea Party keeps trying to politicize. And there’s a question of immigration reform, which is critical as a major part of the progressive coalition. But 10 years from now, 20 years from now, the only thing people are going to be asking of this president is either why he didn’t find the courage to do something on climate change, or they’re going to be asking how he found the courage. I think from the viewpoint of history, this is going to be the issue that he’s judged on.

Q. What are the chief actions that you think he can take?

A. I’m a board member for the Natural Resources Defense Council, and we just put a piece out this week, talking about ways to use the Clean Air Act to sharply reduce carbon pollution from the existing power plants … that would make a tremendous difference.

The other thing he can do is use the power he has as the president of the United States to force a national conversation. We’ve seen a lot of conversation about this fiscal cliff, which is an invented, manufactured crisis, but very little talk about the climate cliff, which is a real, unavoidable crisis. So if we can have the president of the United States on TV every day talking about the manufactured fiscal cliff, then he can use all of those resources to put pressure on Congress to do something about the real climate cliff.

I also think that it is still the case that the best possible way to get the economy moving is to move in a greener direction. You get on an airplane, you fly coast to coast, you look down, and you see a million rooftops that don’t have solar panels on them. You fly over the plains states, acre after acre, you don’t see wind farms and solar farms, even in places that they could exist. There is just tremendous opportunity to home-grow our energy, and put people to work. You land in any city, you are driving past buildings that are leaking energy, because they aren’t using modern energy efficiency technologies. There’s tremendous opportunity there.

So if you look at the economic case, as we begin to move in a greener direction, and you look at a the climate case, this should be more salient than it is. It should be more salient for the public, and I think that’s starting to change, and it should be more pressing for the president — and I hope that that will change.

Q. Do you think environmentalists trying to push Obama further, through protests over the Keystone XL pipeline or, now, the new fossil fuel divestment campaign, actually works? What’s the evidence?

A. I think activism works. You look at the last term, the Latino community kept pushing hard on immigration, and the president came out for the Dream Act. The lesbian, gay, bisexual, and transgender movement kept pushing on the question of marriage equality, and the president came out for marriage equality, which then had a positive effect on public opinion and helped that movement win at the ballot box and in a number of states, within months.

So I think it takes two keys to unlock the door to change: It takes public activism and action, and it takes presidential leadership. But what we’re seeing now is the return of public action and public concern. 350.org is leading that process. The aftershocks of Sandy are going to push that process forward.

Let’s not forget, we have dust bowl conditions developing in the heartland of America, the bread basket of the world, just as Al Gore predicted. That is happening right now. So as the urgency of these disasters moves public attention, and as you see activists marching again, I think there’s an obligation for the president to meet the people on this issue.

This story was produced as part of the Climate Desk collaboration.

Superstorm Sandy — and its revival of the issue of climate change, most prominently through Michael Bloomberg’s sudden endorsement — probably aided Obama’s reelection victory last night. But at the same time, there has been a vast debate about the true nature of the storm’s connections to global warming (as well as plenty of denialism regarding those connections). In fact, there has even been the suggestion, by cognitive linguist George Lakoff, that if we all stopped thinking about causation as something direct (I pushed him, he fell) and rather as something systemic (indirect, probabilistic), then we really could say with full accuracy that global warming caused Sandy. Systemically.

Following this debate, I’ve been struck by the strong impression that people are making things too complicated. Here’s the simple truth: Leaving aside questions of systemic causation — and sidestepping probabilities, loaded dice, atmospheres on steroids, and so on — we can nevertheless say that global warming made Sandy directly and unmistakably worse, because of its contribution to sea-level rise.

“I keep telling people the one lock you have here is sea-level rise,” meteorologist Scott Mandia explained to me recently. “It’s the one thing that absolutely made the storm worse that you can’t wiggle out of.” Mandia is an expert on the subject at Suffolk County Community College, and coauthor of the new book Rising Sea Levels: An Introduction to Cause and Impact.

And how do we know Mandia is right? Here’s the logic.

First, according to sea-level expert Ben Strauss of Climate Central, the sea level in the New York harbor today is 15 inches higher than it was in 1880. Now, to be sure, not all of that is due to global warming — land has also been subsiding. Strauss estimates that climate change — which causes sea-level rise both through the melting of land-based ice, and through thermal expansion of warm ocean water — is responsible for just over half, or eight inches, of the total. As it happens, the estimated sea-level rise [PDF] seen globally since the year 1880 is also roughly eight inches.

So how, then, did global warming directly make Sandy worse? Simple: Sandy threw the ocean at the land, and because of global warming, there were about eight inches more ocean to throw. “The footprint of the flood was bigger, based on roughly eight extra inches of depth,” Strauss explains — eight inches more than there would have been in an admittedly hypothetical world in which Sandy arrived without our burning of fossil fuels or heating of the atmosphere.

The next question is whether those eight inches are really significant, in the grand scheme of things. Sandy’s flood height above the average high tide level (a number that also includes the eight inches attributable to global warming) was 9.15 feet. So you might say, who the heck cares about eight inches?

But as it turns out, eight inches matters a lot. First of all, using Climate Central’s Surging Seas tool, Mandia estimated that 6,000 more people were impacted for each additional inch of sea-level rise. That means, basically, that they got wet when they wouldn’t have otherwise: one inch wetter for some, eight inches wetter for others, and everything in between. “An inch or two could be enough to get over a home’s threshold and down into the basement, or make it into one more subway entrance,” Strauss explains.

Moreover, there is also reason to think that the second inch, so to speak, is worse than the first one. That’s because of basic physics. Water flowing atop a surface — say, a New York City street — has its energy sapped by the friction of dragging along that street. However, if the water level is higher, it’ll flow faster, because the water higher above the surface experiences less friction. “If you had an inch of water running down the street, you’d see all kinds of turbulence in it, which is basically energy being lost,” Strauss explains. “But if the water were a foot above it, you’d see more sheet-like movement, which is a more powerful motion.”

Speed matters a great deal in the context of a storm surge, because the surge is only temporary and will recede. So how far it penetrates before doing so is partly a function of is speed.

And there are still more reasons to think that increasing the size of a storm surge by eight inches really matters. Consider the U.S. Army Corps of Engineers’ “depth-damage” functions [PDF], which the Corps uses to study how much flood damage grows with an increasing water level. The upshot here, says Mandia, is that “the damage is exponential, it’s not linear.” Or in other words, as the water level increases, the level of damage tends to rise much more steeply than the mere level of water itself.

And here’s one more hard reality: If we do nothing about global warming, eight inches of sea-level rise is going to look like small beans. As Mandia notes, the New York State Sea Level Rise Task Force [PDF] estimates up to 2.5 feet of sea-level rise by 2050, and up to 4.5 feet by the 2080s. In these scenarios, global warming’s contribution to every storm surge event would be dramatically worse than it currently is. And while those are worse cases, there’s not any real doubt that waters will rise further; the question is simply by how much, and how fast.

None of which is to say, incidentally, that global warming didn’t influence Sandy in other ways, ranging from its rainfall to the impact of warmer seas on the storm’s overall intensity. In all likelihood, such connections also exist.

At the current moment, Strauss’s tools are not precise enough to say that the portion of sea-level rise attributed to global warming damaged a particular home in a particular place. Nevertheless, based on the evidence presented here so far, the inference is simple and unavoidable: Global warming upped Sandy’s damage, and did so substantially. Not that Sandy wouldn’t have been very bad anyway — it would have — but that it was worse than it would otherwise have been.

“There is 100 percent certainty that sea-level rise made this worse,” says Strauss. “Period.”

This story was produced by Mother Jones as part of the Climate Desk collaboration.

In 2007, I published a book called Storm World: Hurricanes, Politics, and the Battle Over Global Warming. It was inspired by what my family had been through in Hurricane Katrina (I’m from New Orleans), but at the end, I looked forward to what other families and other cities might have to experience — if we don’t start to think in a much broader way about our society’s stunning vulnerability to hurricane disasters.

As I wrote:

Even as we act immediately to curtail short term vulnerability, every exposed coastal city needs a risk assessment that takes global warming scenarios into account … Scientists at the NASA Goddard Institute for Space Studies in New York have been studying that city’s vulnerability to hurricane impacts in a changing world, and calculated that with 1.5 feet of sea level rise, a worst-case-scenario Category 3 hurricane could submerge “the Rockaways, Coney Island, much of southern Brooklyn and Queens, portions of Long Island City, Astoria, Flushing Meadows-Corona Park, Queens, lower Manhattan, and eastern Staten Island from Great Kills Harbor north to the Verrazano Bridge.” (Pause and think about that for a second.)

No need to pause and think any longer — last night, just over five years later, much of it came to pass. And indeed, climate change, a topic embarrassingly ignored in the three recent presidential debates, made it worse.

Last night, southern Manhattan reportedly received a 13.88-foot storm surge, a record high and more than enough to flood much of the city. We’ve all seen the pictures. What’s more, according to Ben Orlove, director of the Master’s Program in Climate and Society at Columbia University, about a foot of that surge would not have been there if not for the sea-level rise already caused by climate change over the course of the 20th century.

So, yes, we knew. We knew well ahead of time that this could happen, and we knew global warming was already making it worse. We knew, but we did virtually nothing. (Well, New York did empanel a sea-level-rise task force, which put out a report — and you can see how that turned out.)

But it’s not just about what we knew — it’s also what we know going forward. We know that if you think this is bad, well, global warming will make it still worse in the future.

Take a recent Nature study [PDF] by climate scientists at MIT and Princeton, looking at future storm surge scenarios under climate change. The researchers used multiple computer model runs to simulate a variety of storm surges hurled at New York City — explicitly looking at future climate and sea-level-rise scenarios. By 2100, New York is projected to experience between one-half and 1.5 meters of sea-level rise. Taking the midpoint of this estimate, or a one-meter sea-level rise, the paper found that what is currently a 100-year storm surge event for New York could become a 20-year event by 2100.

In other words, scientists say, the risk of the “rise of the oceans” is steadily going to increase. And when the next disaster happens, we’ll again realize that they told us so. Just like they did before Katrina, and before Sandy … and before the next big one, whenever it is.

The point is that we have a terrible track record of dealing with long-range risks in this country. This is exacerbated by a presentist, science-phobic mindset on full display in the saga of 2012 presidential debates — which now, in the wake of Hurricane Sandy, looks utterly inane. The debates completely ignored climate change — and then much of Manhattan was flooded. So do we really think that Jim Lehrer, Candy Crowley, and Bob Schieffer are the sort of journalists that ought to be steering conversations between our presidential candidates? And if not, why not?

My answer is simple: because these people aren’t science-minded. They treated climate change as a “boutique issue,” something only of interest to some small band of “climate change people” — and in so doing, they proved they simply aren’t in tune to what is really happening to this country and the planet.

Thus far in America, we’ve gotten the national conversation that we deserve — and the consequence is that we feel blindsided by disasters that somehow never came up until it was too late. In the wake of Sandy, then, how about a resolution? This time around, let’s all vow to think about the future, and about climate change, before the next tragedy strikes.

Starting now.

This story was produced as part of the Climate Desk collaboration.