S.M. Saiful Islam Kabir,  Sundarbans

In the country’s southwest, along the edge of the world's largest mangrove forest—the UNESCO World Heritage Site known as the Sundarbans—climate change is intensifying natural disasters like storm surges, floods, and cyclones. As in many other countries, sea levels in Bangladesh are rising rapidly. If this continues, by 2030, around 710 kilometers of the coastal belt will face severe risk, according to a government survey.

A study conducted by the Bangladesh Inland Water Transport Authority (BIWTA) indicates that excessive carbon emissions by industrialized nations are raising global temperatures. As a result, water levels in rivers and the Bay of Bengal are increasing annually.

Experts warn that the water level is rising by about three centimeters per year, leading to severe erosion. Numerous villages have already been swallowed by the sea and rivers. In 2021 alone, nearly 28,000 people are at risk of being displaced due to river erosion. Furthermore, rising salinity in water is negatively impacting the national economy.

According to BIWTA's findings, the country’s 710-kilometer-long coastline stretches from the Naf River estuary in Teknaf to the Raimangal-Kalindi river on the Satkhira border. The Sundarbans span 125 kilometers of this stretch, while another 275 kilometers include river estuaries and islands, and the remaining 310 kilometers comprise low-lying coastal areas. All these regions are vulnerable to climate-induced disasters.

BIWTA monitors tidal water levels at 53 locations across the coast and rivers, including Cox’s Bazar and the Sundarbans. In 2019, the highest recorded water levels were:Cox’s Bazar: 2.24 meters (July 7, 2:24 PM), Khepupara (Kalapara): 2.11 meters (July 2, 10:10 AM) and Hiron Point (Sundarbans): 3.66 meters (July 2, 6:00 AM). 

By 2021, water levels had risen further: Cox’s Bazar: 2.49 meters (April 26, 10:20 AM),  Khepupara: 2.68 meters (April 25, 10:45 PM) and  Hiron Point: 3.56 meters (June 25, 11:10 AM)

This means Cox's Bazar saw an increase of 0.25 meters, Khepupara 0.57 meters, while Hiron Point saw a slight decrease of 0.10 meters.

According to Md. Alfaz Uddin, Joint Director of the Hydrography (Tide) Division at BIWTA  due to climate change, the Earth’s temperature is rising. Ice from the polar regions such as Antarctica and Siberia is melting, adding more water to oceans and rivers. We're continuously measuring this rise using advanced technology.”

In Kuakata,  former Mayor Anwar Hawlader confirmed  that tides and erosion have increased drastically. Areas that were once wide sandy beaches have now vanished under seawater.

Khan A. Raj, a member of BELA’s Kuakata Network and a college lecturer, states in the last decade, around 3 kilometers of coastline in Kuakata have been lost. Five mouzas, including scenic coconut and tamarisk groves, have disappeared, and three villages have vanished from the map.”

With Chattogram and Mongla seaports located along the coast and Payra Port under construction, coastal areas contribute to 25% of the country’s GDP, housing 25% of the population. But with 743 people per square kilometer, these areas are increasingly vulnerable to natural calamities.

Since 1973, around 1,875 square kilometers of land have eroded into rivers, displacing over 1.7 million people, as reported by the Center for Environmental and Geographic Information Services (CEGIS). Between 2020 and 2021 alone, 34 square kilometers were lost to erosion caused by cyclones, tidal surges, and floods.

Prominent erosion-prone districts include: northern and central districts like Kurigram, Gaibandha, Jamalpur, and Bogura,  Southern regions such as Patuakhali, Barguna, Khulna, and Satkhira and eastern areas including Chattogram and Cox’s Bazar

According to Dr. Ainun Nishat, international water resource and climate expert, eter levels in the coastal zone are rising by 3 centimeters per year, with a 20 cm increase over the last decade in Cox’s Bazar. Salinity in rivers is affecting agriculture and damaging the economy. We need stronger, more sustainable embankments and salt-tolerant crop varieties.”

Dr. Akramul Alam of DUET added,  high carbon emissions are raising both temperatures and water levels, which causes riverbank erosion and salinity intrusion. People are switching from farming to shrimp cultivation, harming biodiversity and depleting freshwater resources.”

According to Md. Mizanul Haque Chowdhury, Additional Secretary at the Ministry of Environment, Forest and Climate Change:

“Developed nations’ emissions are causing harm to countries like ours. We are working on both mitigation and adaptation strategies, but unless global carbon emissions decrease, disasters like cyclones and storm surges will increase.”

CEGIS predicts that in 2021, 13 regions are at high erosion risk, specially  Kurigram: 25 erosion sites across 16 rivers including Dharla, Teesta, and Brahmaputra, Gaibandha, Tangail, Sirajganj, Faridpur: Already experiencing loss of homes and farmland and Jmuna and Padma Rivers: May erode up to 28 square kilometers, destroying roads, embankments, homes, markets, schools, and hospitals.

In short, without immediate action, climate change could push millions more into displacement, destroy vital infrastructure, and jeopardize Bangladesh’s economic and environmental future.