The delta belt is home to approximately 125-140 million people. And over 300 million people are supported by the delta. The density of population in the Delta region is 200 people / sq.km. making it one of the densest regions in the world.
The delta region is a high-rainfall region and receives 60-80 inches of rainfall every year.
One of the greatest challenges people living on the Ganges delta may face in coming years is the threat of rising sea levels caused mostly by subsidence in the region and partly by climate change. An increase of half a meter could result in 6 million people losing their homes in this region. Higher temperatures related to climate change could also bring about more severe flooding of the delta, because of increased melting of snow and glaciers in the Himalayas.
This will cause large-scale displacement and migration of over 6 million people into the inner lands which are already highly populated and face severe pressures and scarcities of food, water and land.
Climate change poses a serious threat to the people living in the low-lying areas of the Ganges-Brahmaputra delta. More than 1 million people in the Ganges-Brahmaputra Delta will be directly affected by 2050 from risk through coastal erosion and land loss, primarily as a result of the decreased sediment delivery by the rivers, but also through the accentuated rates of sea-level rise.
The Sundarbans delta is the largest mangrove forest in the world. It lies at the mouth of the Ganges and is spread across areas of Bangladesh and West Bengal, India. The Bangladeshi and Indian portions of the jungle are listed in the UNESCO world heritage list separately as the Sundarbans and Sundarbans National Park respectively, though they are parts of the same forest. The Sundarbans are intersected by a complex network of tidal waterways, mudflats and small islands of salt-tolerant mangrove forests, and presents an excellent example of ongoing ecological processes.
The ecological balance in the Delta region is complex and very delicate. The area is known for its wide range of fauna. The most famous among these is the Bengal Tiger, but numerous species of birds, spotted deer, crocodiles and snakes also inhabit it. It is estimated that there are now 400 Bengal tigers and about 30,000 spotted deer in the area.
Temperature patterns in the Delta region are consistent with global warming and out of the 10% warmest years from 1900 to 2002 six occurred between 1995 and 2002.
Predictions are accelerated seasonal increases in both temperature and precipitation from 2000 to 2100. The largest changes is expected to occur on the Tibetan Plateau but with the largest effects on the densely populated Flood Plains.