Water turns to sun-baked earth. Illustration courtesy of Shutterstock

As anyone who takes a quick scan at newspaper headlines can see, climate change has the potential to trigger major social transformations. Extreme weather events, such as bomb cyclones, can lead to food insecurity, riots, and mass migration, to name just a few effects.

But this is not a simple, one-to-one relationship. Sometimes, even limited climate change can generate major social transformations, while at other times major climate events can have only limited social impact—due to the built-in resiliency of social, political and economic systems.

To understand why, it makes sense to borrow a concept from the world of physics, and consider the question as what is known as a “tipping point” problem, where a small quantitative change triggers a much larger, non-linear change. Social tipping points are reached when a community shifts from a state of stability to instability: from peace to violence, from a democracy to an authoritarian regime, or from a sedentary lifestyle to emergency migration, among others. They are defined as points within a socio and ecological system at which the social components, driven by self-reinforcing feedback loops, inevitably and often irreversibly lead to a qualitatively different state.

In recent years, significant research has been made to identify the early warning signals for social tipping points. The challenge is that knowledge about the nature of a tipping point does not necessarily make crises more predictable.

Origins. The term ‘tipping point’ commonly refers to the critical threshold where a tiny perturbation alters the state of a system. In physics, the concept was used to designate the exact, precise, minuscule point where a small weight added to a balanced object was enough for the object to topple suddenly. The term was popularized by sociologist Morton Grodzins, who studied race relations in American neighborhoods in the early 1960s.

More recently, climate change experts such as Tim Lenton, who pioneered research on this topic at the University of Exeter, have used the term to refer to abrupt and irreversible changes in the climate system. But in addition to helping us understand the climate itself, the concept of tipping points is useful for understanding the consequences of climate change.

At present, assessments of the social impacts of climate change are often rooted in a deterministic and Malthusian perspective, which assumes that human actions and behavior are determined by external causes—in this case, environmental disruptions—and overlooks the social determinants of changes. In particular, the role of inequalities in shaping the social impacts of climate change is often overlooked. On the contrary, it is often assumed that social transformations, such as migration or conflicts, are unavoidable by-products of climate change, whose magnitude would depend first and foremost of the magnitude of climate impacts. This is especially evident when assessing the future human dimensions of climate change. Numerous studies have attempted to predict the magnitude of future migration: Will there be hundreds of thousands, millions, or billions of so-called climate refugees? And studies have tried to predict the size and scale or any conflicts or pandemics on the basis of different climate scenarios.

But such assessments typically overlook not only the role of inequalities, but also of perceptions and (mis)representations, governance systems, solidarity networks, and cultural values in their evaluation of the future social impacts of climate change. The concept of a social tipping point would enable a more accurate assessment of the future social impacts of climate change—especially for migration and conflict. Consequently, thinking about climate change in terms of social tipping points would advance the understanding of the social impacts of climate change, and our ability to forecast them.

And it’s important to note that climate tipping points do not automatically translate into social tipping points; they are two distinct, independent processes. And that social tipping points can be triggered long before climate tipping points are reached, and are more dynamic.

The recent upheaval in Sudan is a good example of this idea of social tipping points: Lower-than-usual agricultural yields led to a sharp increase in food prices—the price of bread tripled in a matter of weeks. This, in turn, led to a massive upheaval against the regime, which took observers by surprise.

So, social tipping points should be not be confused with the carrying capacity of a community. While the carrying capacity of a community is a fixed, pre-determined limit, social tipping points are constantly evolving.

What matters here is the breach of linearity.

Policymaking at the intersection of climate change and migration. Many studies on the social impacts of climate change adopt a global perspective, seeking to produce global projections for migration flows in particular. But social tipping points can’t be understood at the individual level, nor at the global level, as these scales do not allow for an assessment of the social impacts of climate change—which shouldn’t be confused with the human impacts of climate change.

Many predictions and forecasts of climate migration assume that the magnitude of future climate impacts is the key determinant of future migration flows. Yet the perception of such impacts are just as important—and were usually not considered.

Research has shown that there were very significant differences between actual environmental changes and the perceptions of these changes among the local population. The decision to migrate is usually determined by the perceptions of changes rather than by the changes themselves, and yet this is an aspect that is difficult to consider.

Similarly, the concept of social tipping points can be essential to assess the influence of mitigating factors such as solidarity networks—where members of a social group can rely on each other—on the environmental drivers of migration. Here again, the concept helps us determine when a threshold is reached, and why such thresholds are different according to different people, places, and contexts—including for seemingly similar environmental disruptions.

Policy responses to address the social consequences of climate change, and migration in particular, are quickly shaping up. The Global Compact for Migration, adopted in December 2018, recognizes climate change as a major driver of migration worldwide and suggests a number of steps that can be taken to address the migration challenges arising from climate change and natural disasters. The Task Force on Displacement, established by the Paris Agreement in 2015, has also made a number of recommendations to policymakers in the international climate change negotiations, while the Platform on Disaster Displacement was established in 2016 to supervise the implementation of the Protection Agenda from the Nansen Initiative, which seeks to protect the rights of those displaced by disasters.

As these initiatives yield their first concrete results, it will be of crucial importance to account for the perceptions of climate change impacts in the scenarios for future climate-induced migration. How people will migrate in reaction to climate change impacts will depend not just on these impacts or the policies that are implemented to mitigate them, but also on how those affected perceive these impacts. For this reason, it is essential that policy responses do not consider migration as an unavoidable byproduct of climate change, but rather as a social response induced by a wide array of factors, themselves influenced by climate change.

(This column is by François Gemenne, director of the Hugo Observatory at the University of Liège, in Belgium, a research center dedicated to the study of the interactions between environmental changes and migration. Gemenne is also a lead author for the Intergovernmental Panel on Climate Change. This column is based on a piece drafted for Perry World House and made possible in part by a grant from the Carnegie Corporation of New York. The views expressed are solely the author’s.)