Climate change increases migration worldwide. Over the past 30 years, however, this effect has been considerably reduced as climate change weakens economic growth in the countries of the Global South. This is the research result of a team from the Potsdam Institute for Climate Impact Research comparing the observed migration flows to a scenario without the effects of climate change.
"Climate change reduces economic growth in almost all countries of the world," said Jacob Schewe, and leader of PIKs FutureLab Security, Ethnic Conflicts and Migration and one of the authors of the study published in the journal Environmental Research Letters.
"But it has very divergent effects in poorer and richer countries. Overall, migration related to climate change has increased - but it has done so to a lesser extent than might have been expected. The reason is bitter: in poor countries, many people in need are lacking the means to migrate. They have no choice but to stay where they are," he said.
In their study, the PIK scientists focused on an important factor influencing migration flows -- a country's income level. They examined how climate change affects international migration by analysing countries' income levels from 1990 to 2020.
"Economic growth affects national income levels, which in turn affect migration. Relatively few people migrate from high-income and from very low-income countries. In the case of poor countries, this is partly because many people simply cannot afford to leave," said Christian Otto, PIK scientist and also co-author of the study.
So, very poor people often stay in their home country, even if they are in need or would like to migrate for other reasons.
"Our study was not about displacement caused by natural disasters," added Anders Levermann, head of Complexity Science at the Potsdam Institute, professor at Potsdam University, a researcher at Columbia University in the U.S., and co-author of the study.
"Rather, it was about migration motivated by living conditions. Ongoing climate change is keeping many people in the Global South in poverty, making it more difficult for them to migrate. Thus climate change deprives people of an important way to adapt to its impacts and increases the gap between rich and poor," he added.