Climate change is currently affecting the world as we know it, including our ecosystems, natural resources, and the habitability of certain areas. The geographical distribution of such impacts is uneven across the world, and it disproportionately affects deltas.
Deltas are large tracts of land at low lying elevation, which makes them extremely exposed to sea-level rise and other climate change impacts such as extreme floods, storms, surges, salinity intrusion, and among others. But despite deltas account for only 1% of the global land area, they are home to more than a half billion people.
Let’s take the Ganges Brahmaputra Delta as an example.
The Ganges-Brahmaputra Delta, an area of about 355 km wide along the Bay of Bengal, spreading across the state of West Bengal in India and Bangladesh, is fed by the rivers Ganges, Brahmaputra, and Meghna, along with other tributaries and distributaries. This constitutes one the largest river system on earth and drains some of the highest mountains on the planet, the Himalayas.
The delta, one of the largest in the world, covers some 105,640 sq km and has one of the highest population densities of all deltas. Approximately 140 million people inhabit it and upwards of 300 million people are supported by it. The modern history of settlements in this region dates back to 1757, when land passed from local landowners to the East India Company, who began reclamation in the Sundarbans for rice fields.
The advent of the Anthropocene (after 1950) coincides with Independence for India from the British Empire in 1947. In the postcolonial era, more than five thousand dams have been built to facilitate either irrigation or power generation, submerging homelands of at least 40 million people. At the same time,the delta has seen a rapid increase in population and changes in land character, although it remains one of the most under-developed areas in both Bangladesh and India. The population is mostly dependent on traditional monocrop rice cultivation and riverine/offshore fishing, crab collection, honey collection, among other livelihoods.
The delta is threatened by rising sea levels caused by subsidence and climate change, and half a meter increase could result in 6 million people being displaced. Higher temperatures related to climate change are also anticipated to bring about more severe flooding of the delta, because of increased melting of snow and glaciers in the Himalayas. This will cause large large-scale displacement and migration.
Governments, non-governmental bodies and foreign organisations have been identifying innovative approaches to help the delta populations adapt to change and to reduce vulnerabilities in the face of future uncertainties but have failed to find a comprehensive strategy that accounts for the millions of people that could be displaced.
For further information on the Ganges Brahmaputra Delta and other mega deltas read: Nicholls, R., Adger, W.N., Hutton, C., Hanson, S. (Eds.) (2019) Deltas in the Anthropocene, Palgrave Macmillan.
