Natural calamities have plagued humanity for generations. But with the prospect of worsening climate conditions over the next few decades, experts on migration say tens of millions more people in the developing world could be on the move because of disasters.
Rather than seeking a new life elsewhere in a mass international “climate migration,” as some analysts had once predicted, many of these migrants are now expected to move to nearby megacities in their own countries.
“Environmental refugees have lost everything,” said Rabab Fatima, the South Asia representative of the International Organization for Migration. “They don’t have the money to make a big move. They move to the next village, the next town and eventually to a city.”
Such rapid and unplanned urbanization is expected to put even further strains on scarce water, energy and food resources, said Koko Warner, who works in environmental migration at the United Nations University Institute for Environment and Human Security in Bonn.
In Bangladesh, a largely flat, riverine nation where more than 140 million people live in one of the most densely populated countries in the world, past generations often moved to cities seasonally. They worked to send money home to their villages and usually returned there during planting season.
But in recent years, the moves are more likely to be permanent. More intense storms and floods, salinization damage to crops caused by the encroaching sea and especially worsening river erosion have left many people rootless, Ms. Fatima said.
Dhaka, the capital, is often the only real option in this region. It is the fastest-growing megacity in the world, according to the World Bank. At least 12 million people live in Dhaka, and there are more than 400,000 newcomers each year. The World Bank predicts that the population could grow dramatically by 2020.
Like the rest of Bangladesh, Dhaka is also extremely vulnerable to climate change: It is just a few meters above sea level and is regularly hit by cyclones and floods. The environmental group WWF recently rated it among the megacities most vulnerable to the effects of global warming, after Jakarta and Manila.