Using census-based data, the researchers analysed 107,840 migration flows within 72 countries between 1960 and 2016.
As climate turns warmer and compels people to relocate, droughts could become the main driver of migration and cities are expected to become more populated, according to a study that analysed trends in internal migration in 72 countries over 50 years.
While migration, both within or across a country's borders, has traditionally been seen as an economic or a conflict-related consequence, in recent years, environmental factors have increasingly become significant for people to relocate.
Researchers said that as droughts intensify and regions become more dry, the movement of people accelerates, often leading to a migration towards urban areas, where opportunities could be scarce but are perceived as more stable.
"When faced with environmental pressures like prolonged dryness, many people see migration as their least bad option," said author Marco Percoco, Director of the GREEN Research Center at Bocconi University, Italy.
Using census-based data, the researchers analysed 107,840 migration flows within 72 countries between 1960 and 2016.
"We find that increased drought and aridity have a significant impact on internal migration, particularly in the hyper-arid and arid areas of Southern Europe, South Asia, Africa and the Middle East and South America," the authors wrote in the study published in the journal Nature Climate Change.
Rural areas, especially those dependent on agriculture, were found to be the hardest hit because of climate change. The communities in these regions are most likely to experience the effects of worsening droughts, the researchers said.
In places where farming is the main source of income, drying soils and dwindling water supplies directly translate into lost livelihoods, thereby driving people towards urban areas, they added.
The move to cities is a coping strategy, a way for rural families to adapt to conditions that no longer support their way of life, the authors said.
Urban areas, therefore, become magnets for people fleeing rural ones -- a trend that the researchers said is reshaping urban landscapes as the needs and challenges of the migrants further strain an already stressed infrastructure.
The authors thus called for a holistic approach to address the root causes of climate-induced migration, including proactive strategies to improve support systems in urban areas.
They also highlighted the need for policies that help rural communities adapt to climate change in place, thereby possibly reducing the need for migration in the first place.
Better water management, agricultural innovation, and social safety nets could help stabilise populations and allow people to continue their lives without being forced to move, the authors said.