Nous ne pourrons régler les graves problèmes de notre planète sans coopération. Mais étant donné notre prédilection pour les résultats éclair, il nous faudra développer une nouvelle approche de collaboration pour prendre les décisions majeures qui nous attendent.
No single country acting alone will be able to fix the problems that confront us globally. From climate change to species conservation and the depletion of resources like clean water, choosing an effective response depends on our willingness and ability to cooperate. That means that the solutions to resolving issues like climate change may lie not with the physical sciences that produced the extensive evidence and defined the problem, but with the sciences that study human behaviour, which can test different paths to a solution. And it means understanding that why we decide to cooperate — and to what extent — has become the most pressing issue of our time.
As an environmental scientist, I design experiments that study human behaviour. I want to know what it will take for us to choose to make the sacrifices required to combat the scourges of overfishing, freshwater shortages and climate change.
We know more about why we balk at cooperating. A study I led with researchers from Canada and Germany, published in Nature Climate Change in 2013, found that when the rewards of cooperating are delayed — especially delayed to future generations — people are less likely to make the sacrifices necessary for success. In the real world, our preference for instant gratification encourages some of us to “defect” from group cooperation in order to reap immediate benefits. Our collective-risk game in the lab found that this tendency increases when the benefits of cooperating are delayed to benefit future generations, rather than those alive today.
That lab scenario is what we face when it comes to finding strategies to deal with climate change. The cost of the changes we need to make today — from accepting lower economic growth to carbon taxes or subsidizing renewable energy — are felt immediately, while many of the benefits of these steps that could result in a less-hot planet will be reaped by our grandchildren.
Answers to problems like climate change may lie not in more facts but in a better understanding of how and why we decide to cooperate.
The media coverage of our work focused on our evidence as proof that humans are not behaviourally inclined to make the necessary sacrifices for climate change that humans are not behaviourally inclined to make the sacrifices for climate change. To those who oppose the costs of sacrifice, it was a convenient excuse to avoid action. To others who wonder why we seem incapable of forging cooperation, it provided one answer rooted in science to explain our lack of will.
Our research into decision-making shows that scientists are looking in new places for answers to problems like climate change. After five rounds of international scientific consensus on the state of the climate, the solution probably does not lie in providing more facts about the pace, certainty and potential implications of climate change.
Instead, it may depend on getting the social science right, with a better understanding of how and why we decide to cooperate. It will also depend on the political will.
When it comes to studying human cooperation, scientists usually focus on the tension between the individual and the group. The problem was articulated by ecologist Garrett Hardin in his famous 1968 essay, “The Tragedy of the Commons,” which described how people acting in their own best interest will damage the long-term common good.
Hardin’s initial concern was overpopulation, but the theory has implications for environmental sustainability. We see one such tragedy in action on the high seas, where the benefits of overfishing are individualized as profits to fishing companies but the costs are shared by all who depend on future fisheries. Under such circumstances, the tendency is to overexploit fish stocks. Studies have shown that fish populations that travel the high seas are under greater stress from overfishing than fish populations that stay in national waters.
Significantly, the costs of failing to cooperate are not borne by the generation that overexploits the resource. Instead, they are deferred to future generations of humans and wildlife, adding another tension to the tragedy of the commons: time.
Time is one reason that privatization — often heralded as the antidote to the tragedy of the commons — does not necessarily solve the problem. Mathematical models and real-world evidence demonstrate that overexploitation can occur even when resources are under private ownership, because the mechanism by which we value something received right now more than the same thing received in the future is discounted.
The concept is easy to grasp. People would rather take $100 today than the same amount a year from now. And most people prefer to take $100 today to taking $110 in a year.
This human bias toward instant gratification has grave implications when applied to the exploitation of commons that are at risk, whether it is fish stocks or the atmosphere. If people cannot be convinced to defer rewards, then even private ownership will not be able to halt overexploitation.
And if we are to avert this disaster for the planet and ourselves, we need to better understand the behavioural traits that put it all at risk.
Much has been written on time discounting, and many experiments have tested discounting in individual decision-making. But when my colleagues and I examined the research literature, we found no experiments that introduced discounting into an experiment on cooperation.
In our experiment, we added a time element to a game of collective risk. We gave multiple groups of six participants €40 per person to invest in climate change actions. If participants cooperated and pooled their money for a total of €120 for climate change action, returns on their investment in the form of an additional €45 each were promised. The various groups were offered climate returns on their investment according to one of three time scenarios: one day later; seven weeks later; or in planting oak trees, an intergenerational scenario that would lead to climate benefits several decades down the road but would not personally accrue to the participants.
Although many individuals invested initially in the long-term intergenerational investment, none of the groups achieved the €120 target. The majority of groups cooperated when the benefits were paid out the next day, a minority of groups when the benefits were paid out seven weeks later; but none of the groups that were offered the intergenerational condition cooperated.
Experiments like this help us understand why cooperation on a long time scale is difficult. But they also provide a model where we can test how different interventions work in the lab to explore possible ways to curb discounting and whether some policy interventions might have unintended effects. Our results explain why it is important to find policies that provide short-term benefits. They help to explain why adaptations to climate change — for example, large sand-bars and carbon capture and storage — might be more attractive than mitigation, because the benefits of adaptation would accrue to current generations, while the benefits of some forms of mitigation might provide gains only in the distant future.
Our results also show some curious behaviour that economists would probably diagnose as irrational. While no group in our third, intergenerational treatment succeeded in reaching the €120 target, the average group contribution was still €57, and one group even got as close as €116. We need to find the reason for this intergenerational cooperation. The individuals in our experiment were playing our game for money, but in this third intergenerational treatment, other things they valued obviously came into consideration.
Lab experiments can provide insights into human behaviour, but there are limitations. In the real world, we’re dealing not with six players but with hundreds of countries and corporations, and these countries and corporations come to climate negotiations with different resources, political power and influence. In addition, the costs of climate change and the benefits of mitigation are not evenly distributed across all actors, as they are in our experiment. We know that the tropics and small island states will bear disproportionate punishment for a problem to which they barely contributed. We know certain species, like coral reefs, are going to be less able to adapt to climate change than others.
But the biggest difference, one that is so obvious it feels glib to mention it, is that there is no chance of pressing the reset button, as we can in our experiment. What’s happening to the earth’s atmosphere is not a game, and we cannot start over.