As the planet continues to warm, people living in the world’s most vulnerable regions — like arid or low-lying nations — must contend with the decision to stay in a place where livability is decreasing or leave for countries with more stable climate and economic conditions.

Recent Princeton University research suggests that restrictive border policies could increase many people’s vulnerability to extreme climate conditions and weaken economic prosperity by limiting their ability to emigrate from countries that are facing worsening conditions due to climate change, such as drought, heat waves, and rising seas.

The results also show that open borders have a positive impact on developing countries themselves, especially in places like Central America, Southeast Asia, and small island nations. When people are allowed to move freely, they tend to send more money “back home,” which provides an important source of income for the origin country. This income could also be used to reduce vulnerability to climate change.