This means that the scale of migration will be 10 times bigger than what was seen during the 1947 partition of India or 375 times the number of people displaced by the Sardar Sarovar Project.

The forecast has been made in a report unveiled by the Greenpeace here today.

The report prepared by Sudhir Chella Rajan, a professor in the Department of Humanities and Social Sciences at the Indian Institute of Technology (IIT) Chennai, and commissioned by the Greenpeace, shows that if global temperatures rise by about 4 to 5 degrees in the business-as-usual (BAU) scenario through the course of the century, then the South Asia region could face a wave of migrants displaced by the impacts of climate change.

The study puts together the available data on climatic research, including the reports of Inter-Governmental Panel on Climate Change and Millennium Eco-System Assessment.

The study shows that in Bangladesh, Pakistan and India alone, 130 million people are currently living in low elevation coastal zones (LECZ)—areas that are less than 10 metres above the sea level. Cities like Kolkata, Mumbai and Chennai fall in this zone.