Global migration patterns driven by more than climate change

A new study shows that emigration is more strongly linked to socio-economic factors than climate change.

The findings are published in the journal Nature Human Behaviour.

“Our findings don’t really match the narrative that’s repeated by the public about climate-induced migration,” says lead author Dr Venla Niva from Aalto University, Finland. “When you look at the different factors together, the analysis shows that human development factors are more important drivers than climate.”

Researchers took birth and death data from 216 countries or sovereign states covering the two decades from 2000 to 2019. They fine-tuned their statistics by taking sub-national data for births by dividing 163 countries into 2,555 administrative units; and for deaths by dividing 123 countries into 2,067 administrative units.

The team from Aalto University and the University of Bologna, Italy, built upon research they published last year covering the period 1990 to 2000.

Having high-resolution data allowed the researchers to answer questions that can’t be investigated using coarser data such as national averages.

World map blue and red net migration
Map showing net migration, with blue showing areas of positive net migration and red showing negative net migration. Credit: Matti Kummu / Aalto University.

“There was a real need for a dataset like this, but it didn’t exist. So, we decided to make it ourselves,” says Niva. “Climate factors don’t follow administrative boundaries, so data like this is needed if you want to study these patterns.”

The team’s dataset is available online and can be explored through an interactive map.

Combining birth and death rates with overall population growth, the team was able to estimate net migration. Socio-economic and environmental factors were assessed through the UN’s Human Development Index (HDI) and the aridity index.

High levels of emigration were found in regions in the middle of both scales such as Central America, northeast Brazil, central Africa and southeast Asia.

“It’s not the poorest of the poor who are fleeing environmental disasters or environmental changes. Migration is an adaptation method used by people who have the capacity to move,” Niva explains.

Areas such as the Arabian peninsula, North America, Australia and the north Mediterranean were net receivers of migrating people, despite their high aridity.

“Decision-makers should pay attention to this,” says co-author Associate Professor Matti Kummu, also from Aalto University. “Rather than focusing solely on border closures and combating migration, we should work to support and empower individuals in economically disadvantaged countries. That would help reduce the drivers that compel people to migrate in search of better opportunities.”

Also revealed in the study are differences between migration patterns within countries.

“In France and Italy, for example, there are really interesting differences between north and south, and in Spain there’s an east-west difference. There are so many patterns that national experts could look into, and of course the reasons behind them might be different for each country,” says Kummu.

“There’s a very common belief that urban areas are pulling the people from the rural areas, but that wasn’t the case everywhere. For example, there are a lot of places for example in Europe where the opposite is true.”

“Overall, migration is more complex than people tend to think,” Niva adds. “Our findings contribute to the discussion of where and how migration is happening – it’s not actually a Eurocentric phenomenon, because most migration happens elsewhere in the world.”

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