Faced with rising temperatures, people may seek asylum
- Alison Snyder, author of Axios Science

A young boy in the desert surrounding the refugee camp in Touloum, Chad. Photo: Orjan F. Ellingvag / Dagens Naringsliv / Corbis via Getty Images
Some experts are concerned climate change will drive massive migrations as people are displaced from their homes, and it may already be happening. In a study published today in Science, researchers try to quantify how many people move from where to where under what conditions. They looked at asylum applications into the European Union and the weather in people's country of origin and found that as temperatures rose there, so did the number of people seeking asylum.
The context: It's timely — the U.S. Department of Defense has called climate change a "threat multiplier" and the defense authorization bill signed by President Trump last week acknowledges climate change as a "direct threat to the national security of the United States." Yet that view is noticeably absent from the president's National Security Strategy unveiled earlier this week.
"This is the perfect example of why the [Trump] administration shouldn't be ignoring climate change," says Michael Oppenheimer, a professor of geoscience and international affairs at Princeton University who was not involved in the study but collaborates with the authors.
What's new: Earlier studies found a link between unfavorable changes in climate — which are known to affect agriculture and GDP — in a country (for example, Syria) and migration out of it. The new study looks at the issue across 103 countries of origin and separates people who planned to migrate from asylum seekers who are forcibly displaced. The latter are treated differently under international law and, in turn, government policy, says Oppenheimer.
What they did: Study authors Wolfram Schlenker and Anouch Missirian from Columbia University paired data from the UN High Counsel on Refugees about people seeking asylum in the EU between 2000 and 2014 with the average temperature and total precipitation per month in applicants' countries of origin. They looked at the weather in the country overall and specifically in areas where maize is grown — the rationale there being that a large percentage of people in these countries work in agriculture, which is sensitive to weather fluctuations. Maize is a staple commodity grown around the world.
Asylum applications make up about one-tenth of overall migration but Schlenker says he wanted to focus on them because they are driven by distress. They purposely looked at the impact of climate change before the current refugee crisis. (That too was preceded by a drought in Syria that some researchers think was a factor in conflict there.)
What they found: At an average growing season temperature of about 68° Fahrenheit, which is the optimum one for agriculture, the number of applications for asylum was lowest. As the average temperature rose, so did the number of people from Somalia, Bangladesh and other warmer climate countries seeking asylum. But when cooler countries — such as Serbia and Peru — got warmer, fewer applications were received.
The acceptance rate for asylum application to the EU is less than 10%, Schlenker says. But when there was a spike in applications tied to weather fluctuations, the admittance rate rose to about 30%, suggesting agencies who evaluate the applicants find their cause worthy, he points out.
What comes next: Under one scenario — in which greenhouse gas emissions decline — the researchers predict there could be 98,000 more asylum applications each year by 2100. If emissions continue to rise as they have been, it could lead to up to 660,000 additional applications to the EU each year.
Keep in mind: The scenarios hold all else constant and the world is anything but that. Growing seasons could be adapted. And standards for judging applications for asylum could be become stricter or relaxed, and discourage or encourage people to apply, Oppenheimer says. "The prevalence of conflict and other conditions causing people to want to flee could change in either direction as well." And, the relationship between climate, conflict and migration is a complex one.
The bottom line: "You can't insulate yourself that easily from climate change, given how connected we are," Schlenker says.