Australasian Science: Australia's authority on science since 1938

Climate Is Driving Migration

New Zealand researchers have shown that not only are the effects of climate change influencing people’s decision to migrate, it is actually a more important driver than income and political freedom at the origin country.

Traditionally, research looking into the drivers of migration focuses on economic differences, such as wages and the costs of migration. It has only recently included climate factors.

Dr Dennis Wesselbaum of The University of Otago and Masters student Amelia Aburn of Victoria University of Wellington looked at migration flows between 16 OECD destination countries and 198 origin countries over 35 years. This is the first time data about various potential driving forces of migration, including climatic factors, has been studied over a long time period.

Wesselbaum amassed data from each country on significant weather events and temperatures and data on immigration from 1980 to 2014, then modelled immigration flows over that time to determine patterns and identify significant factors.

That work showed events like storms, floods, heat waves and droughts have different effects on migration. In particular, temperature rise is having a major influence in immigration decisions; intuitively, people are moving away from the negative effects of climate change.

Wesselbaum has also shown that single or unforeseen events, such as storms, can have a long-lasting impact on a country’s immigration figure. Most interestingly, after an increase in temperatures, migration decreases for roughly 4 years before it increases for about 10 years.

This presents an important but tight window of opportunity for policymakers, as the speed of the policy response is crucial in limiting the effects of shocks from such events in origin countries, and therefore the effects on migration.

“Both developed and at-risk countries need more planning and policy to prepare for what is likely to be a growing trend of people wanting to move from countries experiencing climate change,” Wesselbaum said. “Climate refugees have yet to be recognised officially by international law and included in the UN refugee convention, but the predicted 2–3°C rise in global temperature will see climate refugees rather sooner than later.

The discussion paper is at