"The reality is you have over 40 million people, since January of last year, displaced by extreme environmental events," said Bart Edes, director of the bank's sustainable development department. "This gives you a taste of what's to come next."
In 2010, some 30 million people were displaced, some permanently, primarily by devastating floods in Pakistan and China.
The bank on Tuesday launched its report Addressing Climate Change and Migration in Asia and the Pacific, the first to study the link in Asia, which currently accounts for 30 per cent of the world's 200 million migrants.
The report provides policy recommendations to governments on how to mitigate the impact of climate change on migration flows through adaptation measures and climate-aware development strategies.
Six of the world's 10 countries most vulnerable to climate change are in Asia: Bangladesh, India, Nepal, the Philippines, Afghanistan and Myanmar, the report said.//DPA