Almost a decade ago, an editorial in the prestigious scientific journal Nature announced the dawn of a new age, declaring, “Welcome to the Anthropocene.” The Anthropocene—an epoch defined by the massive planetary impact of human behavior—is a time of great anxiety. To varying extents, everyone is affected by diminishing biodiversity, overfishing, and severe climate changes (which is a contributing factor to the extreme weather that we’ve been experiencing lately).Recent data suggests we’re “approaching a state shift in Earth’s biosphere” and creeping up on the dreaded tipping point where the climate abruptly and irreversibly changes. If this happens, new ecosystems will form and pose daunting challenges to plant and animal life across the globe. Catastrophe could result.To avoid as many of the adverse consequences as possible, we need an existential shift in perception that enables us to view humans as Earth’s caretakers who are charged with effectively managing the planet, not exploiting it.Managing the planet’s climate is fundamentally a collective action problem. Solving this dilemma requires globally coordinating behavior so to promote the interests of our species. This is tough because what’s best for the group as a whole may not be best for some individuals, at least not in the short run. Indeed, because individuals often feel tempted to free ride, the allure of egoism can be the death knell of cooperation.For example, when a person drives a car he or she gains all the benefit. But, when the costs of everybody driving add up (in this case via polluting CO2 emissions), the damage greatly outweighs the individual benefits. Barring a radical shift in automotive technology, to bring these costs down in a fair manner everybody needs to drive less—perhaps by more frequently biking, carpooling, or using public transportation.The essence of the problem, then, is Tragedy of the Commons. People want the individual benefits that come from driving, but they also want the reduced costs that come with everybody else driving less. Many folks will feel tempted to continue driving their cars while hoping others step up to the plate. Those who do step up won’t be uniformly seen as altruists; some will view them as suckers. This is the problem of free-riding. And global climate policy suffers the same malady. It wouldn’t do for North America and Europe to make a pact and then be made into suckers by Asia.The recently departed Nobel laureate Elinor Ostrom spent her long, productive career researching collective action and the Tragedy of the Commons. She observed many cases at the local and regional scale where people were able to create institutions that were instrumental in managing commons and preventing over-harvesting of shared resources. She even went so far as to lay out eight core “design principles” for these institutions.Ostrom often noted that her design principles didn’t easily apply to global collective action problems. Among other challenges, global commons include massive complexity and cultural diversity; national governments often hold out for special privileges before making agreements; and, no room exists for major error because experimentation occurs on a single and fragile planet.As we see, collective action is tough and prospects for a solution at the global level are downright dreary. A dominant view on climate change stipulates that we can only undertake a limited number actions. John Holdren, chief science adviser to President Obama, makes it crystal clear that, “We only have three choices: adaptation, mitigation and suffering, and we are going to need a lot of the first two in order to avoid a lot of the third.” “Anybody who thinks there are alternatives,” he asserts, “is smoking dope.”Indeed, we want to dodge as much suffering as possible. Adaptation is important and there are numerous technological possibilities that scientists and engineers are dreaming up to deal with the changing climate. But, we are not yet past the window where mitigating emissions is out of the realm of possibility, and compared to adaptive measures, less expense may be involved. It could be the best option for sustaining quality of life and the environment.A good mitigation scenario requires the biggest three polluters (China, USA, and European Union) agreeing to significantly cut back on emissions. An even more effective arrangement would get buy-in from countries like India, Russia, and Japan. Unfortunately, until incentives change or a shift in ethics occurs, this doesn’t seem likely. It’s obviously more beneficial to China to keep polluting than to worry about greenhouse gases at this point.While we can be optimistic about some modern conditions that facilitate collective action between large, different groups of people (like enhanced opportunities for communication due to the decreased cost and increased power of communication technology), major barriers remain. One of them, as renowned biologist E.O. Wilson notes, is an engrained part of human nature: tribalism.We are especially good at forming groups with others who are like us and competing against groups that are somehow different. In technical terms, we exhibit parochial altruism. We’re altruistic in the sense that members of a tribe, team, or platoon are primed to cooperate and even sacrifice for others in the group. We’re parochial in the sense that altruism tends to exists only in a context that helps us compete with outsiders by solidifying insider loyalty and success. We can see this as a causal factor of heinous beliefs like racism and religious conflict or less dangerous behaviors like strong allegiances to a particular sports team. Tribalism, therefore, inherently is a cooperative enterprise, albeit only to members of an in-group; out-groups regularly get targeted as problematic “others” who don’t need to be dealt with cooperatively.Yes, it’s true we can form and disband groups very quickly. Examples abound of people helping out strangers who they’ve never met and will never meet again. However, this doesn’t refute the evidence that many of the groups we are part of have strong, lasting bonds, and we remain predisposed to favoring in-group over out-groups. The global tensions between China and America render tribalism quite explicit.A host of evolutionary factors account for why human nature disposes us towards in-group vs. out-group behaviors. Our ancestors, for example, were more likely to survive as members of cooperative groups than as lone individuals braving the harsh elements. Due to the scarcity of resources groups had to compete with each other for access to food and shelter. In fact, Ostrom notes that effective institutions often required the ability to exclude outside groups from the resource. This evolutionary logic is illustrated in an oft-quoted passage from The Descent of Man, Darwin states that tribes composed of “courageous, sympathetic and faithful members, who were always ready to...aid and defend each other...would spread and be victorious over other tribes.”Our tribalism may have served an important purpose for our ancestors and for the stewardship of local resources, but climate management via effective mitigation is a global problem, which by definition excludes nobody. This means there aren’t out-groups to compete against and thus encourage in-group cooperation. As stated before, it’s not feasible to just ignore China while the USA mitigates because, in the long run, China’s massive pollution will harm us just as much as them. Low emitting countries could attempt to somehow punish the high polluting countries, but the power dynamics are skewed because the high polluters also carry the most global clout.Given the tension between our evolved tribalism and the global collective action problem of managing our planet, how can we hope to avoid the climate tipping point?Well, before we throw our hands up and just accept our fate, there’s an empirical question that deserves exploration: Can groups with solid boundaries overcome tribalism and cooperate amongst each other, rather than compete, when faced with a collective action problem? To study this question, we designed an experiment that test inter-group cooperation. Without going into too much technical detail, we’ll briefly describe the basic parameters of the experiment and the surprising results that followed.Our experiment used game theory, a widely used tool for studying decision-making and social interaction, to simulate a Tragedy of the Commons type of problem. Participants were broken up into groups, where each group represents a fishing village that must share a common lake with all the other groups. The lake only has a certain number of fish, each group has the option of harvesting a delimited number of fish per turn, and, at the end of each round (that is, after every group has a turn), some of the fish reproduce and augment the number found in the lake. Additionally, participants were able to take fish from the lake and use them to build and stock a private pond that nobody else had access to unless the owner decided to share with others. These private ponds take advantage of economies of scale. That is, the more fish in the pond the more they reproduce and the faster the pond’s stock grows. Since each group had to wait for its turn before making any decisions those groups at the end of the line were at a disadvantage because the earlier groups could harvest their maximum amount, thus leaving fewer fish in the common lake available for later groups. In other words, those handful of groups that came last were in the unlucky position of other groups being able to “screw them over” by over-harvesting from the common lake.The game goes on for eight rounds or until none of the groups can harvest a required number of fish during their turn. The natural inclination for each group is to try to outcompete the others in order to gain the most number of fish before the experiment ends. Now, to up the ante and actually incentivize participants to play for real, we made each fish caught worth something. Since the participants were our students, we put their grades on the line. One fish harvested equals one percentage point on a quiz grade.To add another layer of complexity, the participants played with students from other colleges. The first time we ran the experiment the participants were from Rochester Institute of Technology (upstate New York) and Arizona State University (central Arizona). The second time participants were from ASU and two different classes at Mesa Community College (central Arizona). Since there were scheduling issues (e.g., the classes met on different days and times), each experiment took a few days of class time to complete. This way participants could think about how to approach the problem posed by the experiment and attempt to discuss strategy with other groups. To facilitate communication between distant classes, we set up a private Internet discussion board.If in-group vs. out-group behavior took hold and the groups devolved into competition with each other, only a couple groups could do well. The others would fail. The only way for every group to get good grades is for everybody to cooperate and coordinate their actions so that no group over-harvests the common lake before eight rounds are up. If this is done, there is enough fish for everybody to harvest. However, as we know, there is strong temptation to treat others as suckers, and lots of trust is needed between groups to enact such a cooperative plan. Crucially, since this is a multi-university experiment, participants have to cooperate with groups of people they’ve never met, will probably never interact with again, and can only communicate via the discussion board. Quite the challenge!Remember, Ostrom’s research shows that when certain conditions are met and the institutional design principles are implemented then a common resource like the one illustrated by our experiment could be managed. For example, she observed that sanctions on selfish people is a key aspect. In less academic terms, “If Johnny sees you harvesting more then you're supposed to then he's going to let you know that it's not cool to take more than your share. If you continue to over-harvest then Johnny is going to gather Bob and Ted and they're all going to show up at your door with baseball bats.” However, our game doesn’t allow for any credible threats like that; the groups couldn't rely on robust sanctions. What’s more, the students from different universities had to deal with each other and cooperate through an online discussion board. Realiable face-to-face persusasion was thrown out the window.In addition to combatting tribalism, many ethical issues were at stake in the participants’ decisions and interactions. For example, they had to confront how to deal with the moral luck of some participants being put in a disadvantageous position due to no fault of their own. They had to ask themselves whether an ethical obligation exists to help people whom the instructors placed in groups that took late (and potentially disadvantageous) turns? They also had to decide if an egalitarian solution was the most desirable, and if it wasn’t who deserved more points and for what reasons?Much to our surprise, cooperation prevailed both times we ran the experiment. Even though the built-in incentives and moral tensions should have caused each group to rush and harvest as many resources as possible, they were able to communicate a collective plan—even over geographical distance—and follow through, which lead to every group walking away with an equal outcome.How did the groups overcome all the obstacles in their path to collective action? What were the mechanisms of cooperation?We analyzed the interactions amongst participants as they were taking part in the experiment. We found that much of the coordination and cooperation that occurred was put into motion by individual leaders who emerged from different groups. In other words, whole groups didn’t have to learn to work with others; collective action was choreographed by a handful of leaders working together, who then directed their respective group’s efforts towards a successful solution.We should clarify that when we talk about leaders we don’t mean just any charismatic person who dictates how a group should act. The leaders in this case had an ethical quality. Through their significant contributions they gained everybody’s trust, ensured that group goals were decided on by participatory deliberations amongst any interested members, and didn’t persuade people through casting other groups as the bad guys.In fact, our measure of posts on the discussion board conformed to a power law relationship where most of the contributions came from a small number of people, i.e., those who stood out as leaders contributed far more than everybody else. What’s more, these leaders were able to exert their influence through both face-to-face as well as web-based contributions. As we note above, Ostrom’s recent research emphasized the role of “being able to look others directly in the eye while discussing such moral issues...” However, our results show that even discussion boards could be an effective enough medium for group leaders to arrive at a cooperative collective action solution.What does all of this have to say about the tough problem of climate management and humanity’s responsibility to be good global caretakers? It provides something like a proof of concept. Perhaps people can overcome their fierce tendency to organize the world into those who are in my group and those who are outside of my group. That said, the experiments admittedly were relatively small in scale when compared to the global level.Nevertheless, there is growing evidence that information and communication technology (ICT) can provide crucial infrastructure for widespread deliberation. The recent Arab Spring showed Twitter and Facebook can enhance bandwidth and coordinate mass efforts. The problems of global collective action potentially could be tackled through ethical leaders, like those we observed, using ICT to aid deliberation and decisions of an international contingent. But, at the same time, we realize it is too early to celebrate. Our experiment is structured around many simplifying assumptions, and participatory deliberation might be impossible at the global stage, a domain that includes diverse state actors, institutions, social and cultural norms, and power dynamics.AcknowledgementsThis material is based upon work supported by the National Science Foundation under Grant No. 1134943. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. The Global Institute for Sustainability at ASU also provided support.Jathan Sadowski is a Research Technician in the Global Institute of Sustainability at Arizona State University. Follow him on Twitter @jathansadowskiEvan Selinger is an Associate Professor of Philosophy at Rochester Institute of Technology. Follow him on Twitter @EvanSelingerThomas Seager is Associate Professor of in the School of Sustainable Engineering and the Built Environment at Arizona State University. Follow him on Twitter @seagertp