Sub-Saharan Africa, Central America and Australia could lose the most species of plants and animals.
Severe floods and drought are forcing thousands of people in Bangladesh to flee from their homes to Dhaka.
The capital is home to an estimated 17 million people and close to half that number live in the slums.
Many have lost their homes to river-bank erosion in the south of Bangladesh and have migrated because of the climate change.
In the second part of our series on the effects of climate change in Bangladesh, Al Jazeera’s Jonah Hull reports from Dhaka.