Social tipping as a response to anticipated sea level rise

Social tipping, where minorities trigger large populations to engage in collective action, has been suggested as a key component to address contemporary global challenges, such as climate change or biodiversity loss. At the same time, certain climate tipping elements, such as the West Antarctic Ice Sheet, are already at risk of transgressing their critical thresholds, even within the aspired goals of the Paris Agreement to limit global temperature rise to 1.5° to 2°C. Consequently, recent studies suggest rapid societal transformations, i.e, wanted tipping, may be required to prevent the crossing of dangerous tipping points or critical thresholds in the climate system.

Here, we explore likelihoods for such social tipping in climate action as a response to anticipated climate impacts, particularly sea-level rise. We first propose a low-dimensional model for social tipping as a refined version of Granovetter's famous and well-established threshold model. This model assumes individuals to become active, e.g., to mitigate climate change, through social influence if a sufficient number of instigators in one’s social network initiate a considered action. We estimate the number of instigators as shares of per-country populations that will likely be impacted by sea-level rise within a given time-window of anticipation. Specifically, we consider sea-level contributions from thermal expansion, mountain glaciers, Greenland as well as Antarctica under different concentration pathways. Additionally, we use nationally aggregated social science survey data of climate change attitudes to estimate the proportion of the population that has the potential to be mobilized for climate action, thereby accounting for heterogeneities across countries as well.

Our model shows that social tipping, i.e., the majority of a population acting against climate change, becomes likely if the individuals' anticipation time horizon of climate impacts lies in the order of a century. This observation aligns well with ethical time horizons that are often assumed in the context of climate tipping points as they represent the expected lifetime of our children and grandchildren. We thus show that, even though sea-level rise is generally a very slow process, a small dedicated minority of anticipatory individuals – usually 10–20 percent of the population – has the potential to tip collective climate action and with it a whole ensemble of attitudes, behaviours and ultimately policies.