Well-managed migration can enable migrants to boost sustainable development, research shows.
Sustainable development means enhancing wellbeing in ways that equitably meet needs of present and future generations.
Migration is often viewed as a threat to this – and to stability and security – while the benefits for migrants and host nations and regions are overlooked.
The new research – a set of studies published in the journal Proceedings of the National Academy of Sciences – shows new policies are needed for managing migration to maximise sustainability, and to minimise involuntary displacement due to conflict or disasters.
The studies are based on evidence from a variety of locations including Thailand, Pacific island nations, the world's largest refugee camps, and European and American cities.
"Migrants can be a transformative force in their new locations, bringing energy and ideas that can boost economies – including the green transition," said Professor Neil Adger, from the University of Exeter.
"However, poorly managed migration can deepen inequality and increase environmental damage."
Professor Bill Clark, of Harvard University, said: "To understand properly the relationships between sustainability and migration, we need a comprehensive assessment that includes people who move in search of opportunities to enhance their wellbeing.
"This new research helps to fill these gaps, showing us the impacts of migration – both positive and negative – on the challenges for sustainability governance."
Dr Sonja Fransen, of Maastricht University, said: "At present, sustainability and migration are often managed separately.
"We need new policies that manage migration in the interests of people and the planet, both now and into the future.
"Research to date has tended to focus on people fleeing conflict or disasters."
Dr Ricardo Safra de Campos said: "It is crucial to consider the impact of migration on the places people leave behind, as well as the places they go.
"More than one billion people today are 'lifetime migrants', meaning they live in a place distant from where they were born.
"From a global perspective, only a quarter to a third of these migrants cross international borders.
"The majority consists of people moving within their countries of birth.
"The vast majority of migrants move voluntarily in search of a better life.
"But a growing number – now perhaps 10% of the total migrant pool – move involuntarily, fleeing social or environmental stresses such as conflict and climate change.
"Global averages, however, are only the beginning of the story.
"Most involuntary migrants end up concentrated in a few places relatively near to the places they are fleeing and pose disproportionate challenges there."
The studies in the new collection include one that focusses on three atoll islands in the Pacific region.
It found that people's sense of "belonging" affected the sustainability of those societies. Current patterns of emigration from these areas reduce pressure on natural resources, while emigrant diasporas still support and promote their origin communities through their social and economic ties.
Another paper focusses on Florida, where sea-level rise is expected to lead to outward migration – with younger, economically active adults moving first. Such migration would lead to pressures in destination cities, and aging populations in coastal areas.
Several of the researchers involved in the new studies are working on the MISTY project, an international consortium led by the University of Exeter and funded by Belmont Forum.
The new studies are published in a PNAS special issue entitled: "Migration and sustainable development."
