The collective-risk social dilemma and the prevention of simulated dangerous climate change

Abstract

Will a group of people reach a collective target through individual contributions when everyone suffers individually if the target is missed? This ''collective-risk social dilemma'' exists in various social scenarios, the globally most challenging one being the prevention of dangerous climate change. Reaching the collective target requires individual sacrifice, with benefits to all but no guarantee that others will also contribute. It even seems tempting to contribute less and save money to induce others to contribute more, hence the dilemma and the risk of failure. Here, we introduce the collective-risk social dilemma and simulate it in a controlled experiment: Will a group of people reach a fixed target sum through successive monetary contributions, when they know they will lose all their remaining money with a certain probability if they fail to reach the target sum? We find that, under high risk of simulated dangerous climate change, half of the groups succeed in reaching the target sum, whereas the others only marginally fail. When the risk of loss is only as high as the necessary average investment or even lower, the groups generally fail to reach the target sum. We conclude that one possible strategy to relieve the collective-risk dilemma in high-risk situations is to convince people that failure to invest enough is very likely to cause grave financial loss to the individual. Our analysis describes the social window humankind has to prevent dangerous climate change.cooperation ͉ public good ͉ threshold

Is regulation by milestones efficiency enhancing? An experimental study of environmental protection

“…Our results are similar to Milinski et al (2008) we have implemented in a deterministic way, seems to provide a best case scenario for environmental protection. These and our observations imply that regulation by milestones, depending on the specific scenario, can be efficiency enhancing.…”

“…Milinski et al (2008) introduce and experimentally analyze a collective-risk social dilemma, framed as dangerous climate change. The players were endowed with e40 each and could continuously contribute e0, e2, or e4 to a "climate change account" over ten rounds.…”

The level of climate-change mitigation depends on how humans assess the risk arising from missing the 2°C target

“…The collective-risk social dilemma has characteristic features that, taken together, distinguish it from other social dilemmas and other instances of decision-making under uncertainty (Milinski et al, 2008): (i) people have to make decisions repeatedly before the outcome is evident, (ii) investments are lost (that is, no refunds), (iii) the effective value of the public good (in this case, the prevention of dangerous climate change) is unknown, and (iv) the remaining private good is at risk if the target sum is not collected. The climate game involves investing in a public good, not in order to realize a gain but to avoid a loss.…”

“…But cooperation is undermined by free-riding-the hope that others will compensate one's own less-than-fair contributions, a compensation that causes the group to reach the target while maximizing the particular individual's profit. If too much free-riding occurs, because of too frequent emphasis on immediate self-interest, the collective target is missed and everyone loses (Milinski et al, 2008).…”

“…We use the framework of the collective-risk social dilemma that we established previously (Milinski et al, 2008) to investigate the dilemma inherent in avoiding dangerous climate change: Will a group of people reach a collective target through individual contributions when everybody suffers individually if the target is missed? The dilemma arises because every player can gain only if the group reaches the target, requiring sufficient cooperation (fair-share or even altruistic contributions).…”