Whilst developing our model, we unexpectedly discovered that the mathematical framework that had been the state-of-the-art for modelling migration in the past two decades (known as ‘gravity models’) contained a previously unnoticed fundamental flaw. This discovery questions the conclusions drawn in a large number of publications regarding the effects that certain economic, demographic, environmental, and other variables have had, or will have, on international migration.
We published these findings in: Beyer, Schewe, & Lotze-Campen (2022): “Gravity models do not explain, and cannot predict, international migration dynamics”. Humanities and Social Sciences Communications, 9 (56),
https://www.nature.com/articles/s41599-022-01067-x(opens in new window).
We identified how the issue can be mathematically solved, but found that when doing so, migration dynamics turn out to be considerably more difficult to model than previously thought, and that even relationships assumed to be very robust disappear in the analysis.
Submission of these findings to an academic journal is expected for January 2023: Beyer, Abel, Manica, & Lotze-Campen (2022): “Big challenges for causal modelling of international migration dynamics”.
Moving to a different mathematical approach, we investigated the more narrow question of whether climate-related internal displacements increase international out-migration. Finding no statistically significant evidence for this, our analysis lends support to earlier qualitative works that questioned future large-scale climate-induced migration flows from Africa to Europe.
These findings are currently being under review: Beyer, Sedova, Schewe, & Lotze-Campen (2022): “Global effects of conflict- and disaster-induced displacement on internal and international migration”.
