Academics within Lancaster’s Psychology Department have recently published a paper exploring why increased certainty concerning the thresholds for dangerous levels of climate change – demonstrated in the form of a catastrophe avoidance game – can encourage people to take an active part in stopping climate change.

Lancaster’s Dr Mark Hurlstone, alongside academics Dr Ben White (School of Agriculture and Environment, University of Western Australia) and Dr Ben Newell (Institute for Climate Risk and Response, University of New South Wales) undertook a piece of experimental research to demonstrate the role threshold uncertainty plays in climate inaction. For years, climate change – and the need to limit global temperature increase to under 2°C – has been at the forefront of political discussion. However, the lack of scientific certainty around the specific “dangerous” limit has also impeded cooperation on an international level. Previous experiments looking into how levels of uncertainty impact people’s behaviours in relation to the climate crisis have found that greater degrees of uncertainty – for example, whether the “dangerous” level of global warming is 2 or 1.5°C – leads to the collapse of cooperation in groups, and ultimately to missed targets.

Dr Hurlstone and the team therefore wanted to test if adding additional mechanisms – such as an early warning system – could reduce this uncertainty and improve cooperation within groups tasked with tackling climate change. For the experiment, the team recruited 240 individuals to take part in a catastrophe avoidance game. In the game, six-player groups were given $40 each that they could invest into a catastrophe avoidance fund over a series of rounds. If the group did not collectively invest enough money to reach a threshold amount, each individual would lose 90% of their remaining money. The experiment had four experimental conditions. In the certainty condition, groups were told the threshold amount was $120, whereas in the uncertainty condition they were informed it was a random amount between $0 and $240. In two additional conditions, groups were initially given the same information as the uncertainty condition, but then received an early warning signal mid-game that reduced the uncertainty about the threshold location. In the wide-warning condition, they were told the threshold was now between $84 and $156 (a 70% uncertainty reduction), whereas in the narrow warning condition they were told the threshold was now between $108 and $132 (a 90% uncertainty reduction).

The team found that groups in the narrow warning condition began to cooperate significantly more than those in either the uncertain or the wide warning groups upon receiving their warning. The team’s results show that early warnings can help catalyse collective action, but only if the uncertainty is substantially reduced. Their estimate is therefore that the uncertainty needs to be narrowed to within about 10% of the true threshold value for any meaningful effect on cooperation to emerge.

On the findings of their research, Dr Hurlstone commented: “In our newly published paper, we examined how countries cooperate to avoid crossing a dangerous climate threshold—specifically, limiting global temperature rise to 2°C—under conditions of scientific uncertainty about where that threshold actually lies. We tested whether early-warning signals that reduce this uncertainty can improve cooperation amongst our participants in our climate catastrophe game.

Our current research is exploring a more complex, and ultimately more realistic scenario: what happens when early-warning signals not only reduce uncertainty about the threshold location but also shift expectations about where that threshold lies? For example, countries may initially aim to limit warming to 2°C under uncertainty, but then receive new information suggesting the threshold is actually closer to 1.5°C, with either moderate or high confidence.

This raises two key questions. First, does receiving this new information mid-course make countries more likely to avoid the 1.5°C threshold compared to those who were aiming for 1.5°C all along? Second, does it make them more likely to avoid the 2°C threshold compared to countries that never received the revised information? We hope that our upcoming research will soon be able to answer these questions.”

https://doi.org/10.1098/rsos.240425