"Without the right planning and support, people migrating from rural areas into cities could be facing new and even more unsafe risks", Kanta Kumari Rigaud, team lead of the report, said in a statement.
He laid out three key actions governments should take: first, to accelerate their reductions of greenhouse gases; second, for national governments to incorporate climate change migration into their national development planning; and third, to invest in further data and analysis for use in planning development.
"Climate change-driven migration will be a reality, but it does not need to be a crisis, provided we take action now and act boldly", said John Roome, a senior director for climate change at the World Bank group.
According to the report's worst-case-scenario prediction, Sub-saharan Africa could see as many as 86 million internal migrants, South Asia could see up to 40 million, and Latin America could see 17 million.
The report said Ethiopia's population could nearly double by 2050 and migration will rise due to diminishing harvests. Another study was conducted in Bangladesh, where "climate migrants" are likely to outnumber all other types of IDPs (internally displaced persons) by 2050.
And in Mexico, people increasingly will gravitate towards urban areas away from more vulnerable regions.
The research team, led by World Bank Lead Environmental Specialist Kanta Kumari Rigaud and including researchers and modelers from CIESIN Columbia University, CUNY Institute of Demographic Research, and the Potsdam Institute for Climate Impact Research - applied a multi-dimensional modeling approach to estimate the potential scale of internal climate migration across the three regions.
The region's inhabitants now number more than one billion but will rise to 2.7 billion people by 2060, according to World Bank figures.
Researchers believe the number could be reduced by 80 percent if countries reduce emissions, account for migration in development planning and make investments in studying the process of internal climate migration.
"Without the right planning and support, people migrating from rural areas into cities could be facing new and even more risky risks", the report added.