Heat Drives Away More People Than Natural Disasters: The Impacts of a Warming World

What's better at driving people away--hurricanes or heat? It turns out that while dramatic storms may temporarily shift a population, heat is the real driving force. Scientists have found that global warming may lead to more permanent population shifts in the future.

The researchers decided to focus on Indonesia for their study. This multi-island tropical nation is vulnerable to both climate change and larger events such as earthquakes and landslides. This means that the nation is the perfect case study in order to determine what factors play a role in population migration.

In order to learn a bit more about what might cause shifts in populations, the scientists examined 15 years of migration data for more than 7,000 families in Indonesia. In the end, they found that increases in temperature and rainfall influenced a family's decision to permanently move to another one of the country's provinces. In contrast, natural disasters such as floods and earthquakes had a much smaller to non-existent impact on permanent moves.

"We do not think of 'environmental migrants' in a broad sense; images of refugees from natural disasters often dominate the overall picture," said Pratikshya Bohra-Mishra, the first author of the new study, in a news release. "It is important to understand the often less conspicuous and gradual effect of climate change on migration. Our study suggests that in areas that are already hot, a further increase in temperature will increase the likelihood that more people will move out."

More specifically, the researchers found that people start to rethink their location with each degree that the average annual temperature rises above 77 degrees Fahrenheit. In fact, the chances that a family will leave an area for good in a given year rise with each degree. From 80.6 to 82 degree Fahrenheit, chances jump to 1.4 percent.

The findings are important for understanding the impact of future climate change and warming temperatures in certain areas. As temperatures rise, it's likely that people will move to cooler regions in an attempt to escape the heat.

The findings are published in the journal Proceedings of the National Academy of Sciences.