One would think that climate-influenced human migration, especially in Southeast Asia, would move away from coastal areas that would be flooded by the sea level rises, especially those who are already experiencing more severe flooding.

But that’s not what researchers in the United States and Europe are projecting. Led by Dr. Andrew Bell of New York University, the research indicates this bass coastal areas like Bangladesh, will gain more residents than they will lose.

This will happen even if the rising waters cause more frequent and severe coastal flooding, with the concomitant permanent loss of land, episodic flooding of land, salt water intrusion into drinking water sources, erosion. increased and loss of agricultural productivity.

Global sea level began to rise after the end of the last Ice Age, but has accelerated a little since the early 20th century, an era that we affectionately call the Anthropocene. Between 1900 and 2016, the mean sea level globally rose by 16 to 21 cm (6.3 to 8.3 inches). More precise data collected from satellite radar measurements (see figure below) shows an accelerated increase of 7.5 cm (3.0 inches) from 1993 to 2017, which corresponds to a trend of about 30 cm (12 inches) per century.

In all of the scenarios modeled by the research team, a large number of people have headed for danger, which co-author Scott Kulp, Ph.D. (Climate Central) says could trap residents in them. high risk areas.

The study used agent-based models to simulate individual decision-making about whether and where to move. Modeling has shown a number of economic factors driving migration from safer rural areas to cities with higher flood risk, where populations have grown despite the growing potential for property damage and financial loss.

The results contradict conventional assumptions that rising seas will encourage migration away from vulnerable coasts. Therefore, country planning for adaptation and resilience cannot assume that people will be safe from harm.

The research team developed an empirically calibrated agent-based model of household migration decision making that captured the multifaceted push / pull and docking influences on household-level migration. . These constitute a complex set of social, economic, political and demographic conditions in coastal and inland areas.

It’s not just about finding short-term jobs, but the short-term economics are extremely important. And coastal cities have jobs that simply pay better than rural areas, whether they are manufacturing, retail, or high-tech jobs.

Other groups of people are immobilized because they cannot find better livelihoods. One conclusion revealed that access to credit was the biggest obstacle to endangering coastal areas.

The group then exposed around 4,800,000 simulated migrants to 871 coastal flood scenarios projected into the 21st century as part of future emissions trajectories. In none of their predictions did the flooding occur on a scale large enough to push people away from the coast.

One of the main reasons for this surprising result is that while the floods do not accelerate the transition from farm income opportunities to non-farm income opportunities, livelihood alternatives are most abundant in coastal cities.

At the same time, some coastal populations are unable to migrate, as flood losses accumulate and reduce their set of livelihood alternatives, becoming what are called trapped populations.

However, even when modeling increased access to credit, a commonly proposed policy lever to encourage migration in the face of climate risk, they found that the number of agents standing still was actually increasing.

These results imply that instead of a direct relationship between displacement and migration, projections should take into account multiple mobility constraints and preferences. Their results demonstrate that policymakers seeking to affect migration outcomes around sea level change should consider adaptive behaviors and individual-level motivations that change over time, as well as the potential for unintended behavioral responses.

This research shows that changes in society as a result of global warming are going to be a lot more complicated than you think.