On the banks of the Karnaphuli River, in the Bay of Bengal, the port city of Chittagong is Bangladesh’s second largest city, with a population of two and a half million people, many of them refugees from parts of the countryside that have become uninhabitable due to the floods that hit Bangladesh each year during monsoon season. The rains also affect the city as streets are submerged, marooning those living in the low-lying areas. Local rickshaws navigate the waist-deep water, the pullers and drivers taking advantage of the bad weather by demanding excess fares from the commuters. As these annual weather events become more extreme, causing fatal landslides and widespread disruption, can the city ever return to business as usual?

Bangladesh is a country extremely prone to the effects of climate change. The monsoon season is sandwiched between two cyclone seasons - a period of uncertainty that runs from March to December. Even relatively subtle changes in the weather patterns are already having a big impact on the country.

According to a 2017 report by the Food and Agriculture Organisation of the United Nations, Bangladesh emits only 0.3% of the world’s emissions but is the victim of some of the worst effects of climate change. And those changes are leading people to leave their homes. A 2011 report by the UK government found that “rural-urban migration can be a coping strategy for households affected by environmental events”.

The report quotes a survey from the island of Hatia, off the coast of Bangladesh, which found that 22% of households used migration to cities as a coping strategy following tidal surges, and 16% following riverbank erosions. The same report found that the population of Dhaka, the capital city, increased from 1.4 million in 1970 to 14 million in 2010, and is expected to rise to 21 million by 2025. A UN-Habitat report in 2010 found that around 30% of the population of Dhaka were living in slums or informal settlements.

The International Panel on Climate Change estimates that, by 2050, Bangladesh’s population at risk of sea level rise will increase to 27 million. But the issue is not just confined to Bangladesh. British environmentalist Norman Myers predicted that as global warming takes hold there could be as many as 200 million people affected by disruptions of monsoon systems and rainfall, severe droughts, sea-level rise and coastal flooding.