A behavioral experiment shows that a completely uncooperative behavioral strategy undermines climate protection efforts even when disasters are looming
Political conferences can be the scene of fierce negotations. Agreements are often reached at the last minute. A strategy, which extorts cooperation from others, has proven especially successful.
© Oliver Berg/dpa
To the Point
- Short-term effect: In the experiment, simulated climate events increase contributions only temporarily without improving overall success.
- Success depends on group dynamics: Cooperative individuals compensate for deficits, while strategically restrained actors benefit from this.
- Explanation for real-world blockages in climate action: Strategic restraint reduces overall climate protection contributions.
Extreme weather events are becoming more frequent. It is often assumed that rising levels of damage will naturally lead to stronger climate action: once people feel the consequences, the thinking goes, they will act more decisively. A new study led by Manfred Milinski from the Max Planck Institute for Evolutionary Biology in Plön, Germany, and Stefania Innocenti (University of Oxford) casts doubt on this assumption. The findings suggest that even repeated climate damage is not enough to reliably strengthen collective action.
In a laboratory experiment, groups of six took part in a "climate game" played over ten rounds. Each participant was given a starting budget and, in every round, decided whether to contribute nothing, a medium amount or a higher amount to a shared climate fund. Only if the group reached a fixed target sum by the end were all participants allowed to keep their remaining money. If the group missed the target, there was a high chance that the entire remaining budget would be lost - standing in for a climate catastrophe.
Simulated extreme events
Some groups were also exposed to simulated extreme events. In certain rounds, everyone suffered financial losses - but only if the group had not invested enough up to that point. In one version of the game, these losses stayed relatively small; in another, they increased sharply from one event to the next.
The outcome was clear: shortly before the critical rounds, many groups did step up their contributions. But the effect did not last. Between events, payments quickly fell back again. What really mattered was something else altogether. Whether a group reached the climate target depended less on how often or how severely damage occurred, and far more on who made up the group.
Extortionate strategy often worked
The researchers observed two recurring types of behaviour. Some participants acted consistently cooperatively: they reliably paid their share - roughly what would be required if everyone behaved in the same way. Others, by contrast, contributed very little. They gambled on the fact that the rest, fearing a shared loss, would put in more. This "extortionate" strategy often worked. Those who paid in the least were frequently able to walk away with far more money than those who stepped in to cover the gap.
From the perspective of the cooperative participants, this behaviour was still rational. As long as the target remained within reach, their best option was to close the shortfall - even though this effectively rewarded free riding. Only once too many people held back did the system collapse. At that point the group failed to hit the target, and the losses affected everyone - including those who had barely contributed at all. The "extortionists" represent a fixed behavioural type. As the study shows, they cannot be disciplined. In this and other studies, they account for around 40 per cent of participants - and are therefore very likely to exist in similar proportions in real life. The fact that global CO₂ emissions and the associated rise in temperature continue unchecked shows just how much these natural extortionists overburden those who try to act fairly.
Overall, the study paints a sobering picture that reaches far beyond the lab. Damage and risk alone do not automatically produce cooperation. When a significant share of those involved consistently fails to pull their weight, the pressure on the committed grows - until their ability to compensate runs out. From the authors' point of view, this highlights the need for binding rules and political tools that support collective action and limit free riding. Simply hoping that disasters will bring about insight is not enough.
