Tens of millions of people in some of the world's poorest areas could be displaced by climate change in just a few decades, the World Bank has warned in a report.
The report, "Groundswell -- Preparing for Internal Climate Migration," suggests that more than 143 million people across South Asia, Sub-Saharan Africa and Latin America are at risk of the effects of "slow-onset" climate change.
Droughts, crop failure, and rising seas could force millions to move to other places within their countries to areas that are potentially unprepared for an influx of extra people, the report said.
The report suggests that this type of migration will rise until 2050, then "accelerate unless there are significant cuts in greenhouse gas emissions and robust development action."
The numbers include 86 million potential migrants in Sub-Saharan Africa, 40 million in South Asia and a further 17 million in Latin America -- three regions which represent 55% of the developing world's population.
"Every day, climate change becomes a more urgent economic, social, and existential threat to countries and their people," World Bank CEO Kristalina Georgieva wrote in the introduction to the report.
"Increasingly, we are seeing climate change become an engine of migration, forcing individuals, families and even whole communities to seek more viable and less vulnerable places to live."
"The poorest and most climate-vulnerable areas will be hardest hit," the report suggests, and the impact most keenly felt in "out-migration hotspots" like low-lying cities and coastal areas and "areas of high water and agriculture stress."
The trends will be inverse in "in-migration hotspots," which will see the worst influxes of climate migrants, and will suffer as a result due to the added stress on their services and resources.
"Many urban ... areas will need to prepare for an influx of people, including through improved housing and transportation infrastructure, social services, and employment opportunities," the report says.
The report predicts that these two types of migration hotspots will emerge by 2030 and likely multiply by 2050. However, neither is pre-destined and the worst effects could be mitigated by "planning and early action."
In addition to cutting greenhouse gas emissions, the report suggests that governments, particularly in these areas, need to fold in climate migration as part of their development planning, and to study the phenomenon to better understand it.
However, even if a "climate-friendly" scenario is implemented, the scale of the issue is such that anywhere between 31 and 72 million people could still be displaced across the three regions.