The State of Bangladesh Climate

Executive Summary

Bangladesh emits 0.52 metric tons of CO2 per capita, approximately 11% of the global average of 4.7 metric tons, while ranking #7 on the Global Climate Risk Index. The country's total emissions of 89.0 million tonnes represent approximately 0.24% of the global total, yet 17% of its land area faces permanent inundation from a one-metre rise in sea levels, and more than 30 million people reside in the coastal flood zone. With adaptation spending of $1.0 billion per year against estimated loss and damage of $2.0 billion annually, Bangladesh exemplifies the fundamental inequity of the global climate system: those least responsible for emissions bear the greatest physical and economic burden.

Emissions and Carbon Footprint

Bangladesh's emissions profile presents one of the starkest illustrations of climate injustice in the global system. At 0.52 metric tons of CO2 per capita, the country emits roughly one-thirtieth of the per-capita output of the United States (15.5 tonnes), one-fourteenth of China (7.4 tonnes), and substantially less than the global average of 4.7 tonnes. Total emissions of 89.0 million tonnes place Bangladesh at approximately 0.24% of global CO2 output, a modest contribution from a nation of over 170 million people. The cumulative historical contribution is even more negligible: Bangladesh's total CO2 emissions since industrialization began amount to less than what the United States emits in a single year.

Methane emissions of 120.0 million tonnes of CO2 equivalent add a significant dimension to the emissions profile. The primary sources are rice paddy cultivation, which produces methane through anaerobic decomposition in flooded fields, and livestock. These are not discretionary emissions from luxury consumption; they are the metabolic byproduct of feeding 170 million people in a densely populated agrarian economy. Alternate wetting and drying (AWD) techniques for rice can reduce paddy methane by 30-50%, but deployment requires extension services, farmer training, and investment that compete with other urgent development priorities. Renewable energy accounts for 25.0% of the energy mix, a meaningful share that underscores how far the transition must travel. Bangladesh's 2021 updated Nationally Determined Contribution (NDC) commits to a 22% unconditional emissions reduction, but achieving this target requires replacing natural gas dependence (approximately 60% of the energy mix) with renewables, building on the successful Solar Home Systems programme that has deployed over 6 million units.

Climate Vulnerability and Physical Exposure

Bangladesh's rank of #7 on the Global Climate Risk Index reflects a convergence of geography, demography, and hydrology without parallel among major economies. The country sits almost entirely on the Ganges-Brahmaputra-Meghna delta, the world's largest and most active river delta system. At 1319 people per square kilometre, Bangladesh concentrates enormous human and economic value in zones of extreme physical exposure.

Sea level rise of 3.5 mm/year in the Bay of Bengal, combined with land subsidence of 3-18 mm/year from sediment compaction and groundwater extraction, produces effective relative sea level rise among the highest in the world. A one-metre rise, within the plausible range under IPCC SSP5-8.5 by 2100, would permanently submerge approximately 17% of Bangladesh's total land area, affecting some of the most productive agricultural districts, the Sundarbans mangrove ecosystem, and urban centres including Khulna, Barisal, and parts of Chattogram.

Cyclone frequency and intensity in the Bay of Bengal have been increasing, with a major cyclone striking approximately every 3 years. Bangladesh has built what is widely recognized as the world's most effective community-based cyclone preparedness system. The transformation is extraordinary: Cyclone Bhola in 1970 killed 300,000-500,000 people; Cyclone Sidr in 2007 (Category 4) killed approximately 3,400; Cyclone Amphan in 2020 killed 26 people in Bangladesh. This 100-fold mortality reduction was achieved through a network of 4000 concrete cyclone shelters, the volunteer-based Cyclone Preparedness Programme (CPP), and institutional coordination between the Bangladesh Meteorological Department and local government. This remains one of the most remarkable disaster risk reduction success stories globally.

Annual flood exposure averages approximately 20% of national territory, with mega-flood events in 1998, 2004, and 2017 inundating 50-70% of the country. Flash flooding in the northeast haor wetlands and drought in the Barind tract of the northwest represent additional climate extremes that affect distinct populations and agricultural systems.

NDC Implementation and Adaptation Finance

Bangladesh's 2021 updated NDC commits to a 22% unconditional emissions intensity reduction, with a conditional target of 27% given international support. The NDC is complemented by a suite of climate policy instruments: the Bangladesh Climate Change Strategy and Action Plan (BCCSAP, 2009), the National Adaptation Plan (NAP, 2023), the Mujib Climate Prosperity Plan, and the Bangladesh Delta Plan 2100. Climate budget integration, pioneered through the Climate Fiscal Framework, has embedded climate considerations into 25 ministries' budgetary planning.

Adaptation spending of $1.0 billion per year, combining domestic budgetary allocation and international donor contributions, falls significantly short of estimated needs of $5-7 billion annually. The Bangladesh Climate Change Trust Fund (BCCTF), established in 2010, has disbursed over $400 million for adaptation projects, demonstrating that domestic institutions can programme climate finance at scale. However, access to the Green Climate Fund (GCF) has been constrained by complex application procedures, limited absorptive capacity of implementing entities, and the mismatch between GCF programming cycles and adaptation urgency.

Annual loss and damage of $2.0 billion represents the residual cost that adaptation cannot prevent. Bangladesh's leadership at COP27 in securing the establishment of the Loss and Damage Fund was a landmark moment in climate diplomacy, but initial pledges of approximately $700 million globally fall far short of the estimated $400 billion in annual loss and damage across developing countries. An estimated 7.0 million internal climate migrants have been displaced by sea level rise, salinity intrusion, riverbank erosion, and cyclone damage, many migrating to Dhaka's informal settlements where they face secondary climate vulnerability from waterlogging and heat stress.

Land Use, the Sundarbans, and Food Security

Forest cover at 14.5% is below target, 2.5 percentage points below the 17% Aichi Biodiversity Target. The Sundarbans (6017 sq km), the world's largest contiguous mangrove forest, provides ecosystem services valued at billions of dollars annually: coastal storm surge attenuation reducing cyclone damage by an estimated 20-30% in adjacent districts, fishery nursery habitat supporting millions of livelihoods, and globally significant carbon sequestration. IPCC projections suggest that a 45 cm sea level rise would permanently inundate 17% of the Sundarbans, degrading this critical natural infrastructure.

Arable land at 60.6% of total area faces compounding pressures from saltwater intrusion (approximately 1.02 million hectares of coastal agricultural land affected), riverbank erosion (consuming 10,000-15,000 hectares per year), and conversion to built area as Dhaka's metropolitan footprint expands. The saline front in the southwest has advanced inland by 100+ kilometres over the past two decades, reducing rice yields in affected districts by 15-25%. As salinity intrusion continues, the food security implications for a nation heavily dependent on domestic rice production are severe.

Air Pollution

Dhaka's annual average PM2.5 concentration of 77.1 ug/m3 is approximately 15 times the WHO guideline of 5 ug/m3, making it one of the most polluted capitals in the world. An estimated 80,000 premature deaths per year are attributable to air pollution (IHME GBD 2019), with an economic cost estimated at 3.9% of GDP (World Bank 2022). Major sources include brick kilns (approximately 7,000 operating with outdated technology), vehicle emissions from an aging and poorly maintained fleet, industrial emissions, construction dust, and transboundary pollution from crop burning in neighbouring states. The brick kiln sector is the single largest point-source contributor. Conversion to improved technologies (Hoffman, tunnel, or zigzag kilns) could reduce emissions by 40-60% but requires both regulatory enforcement and financing support.

Climate Migration, Urbanization, and Energy Transition

An estimated 7.0 million people have been internally displaced by climate impacts, with 300,000-400,000 migrating to Dhaka annually. Urban population at 32.7% and growing at approximately 3% per year places mounting pressure on housing, water supply, sanitation, and drainage in Dhaka, already one of the world's most congested megacities. Informal settlements in low-lying areas of the capital are themselves acutely vulnerable to waterlogging, heat stress, and disease, creating secondary climate vulnerability among populations that fled primary climate impacts.

The renewable energy share at 25.0% is inadequate and lags behind regional peers. India has surpassed 12% renewable share through competitive solar auctions; even Pakistan has achieved higher renewable penetration. Bangladesh's energy mix remains dominated by natural gas (approximately 60%), with domestic reserves depleting and the country increasingly reliant on imported LNG. The tension between development needs and climate commitments is real: the question is whether energy expansion locks in fossil fuel dependence for decades or pivots toward renewables and distributed generation.

Outlook, Risks, and Policy Implications

Bangladesh's climate trajectory is defined by three reinforcing risks:

• Accelerating sea level rise and permanent land loss: Current projections indicate 14-32 cm of additional sea level rise by 2050 under moderate scenarios, with the upper bound under high-emission pathways reaching 50+ cm. Combined with land subsidence, the effective rate of relative sea level rise will progressively shrink national territory and eliminate productive agricultural land.
• Saltwater intrusion destroying agricultural productivity: The saline front has advanced 100+ km inland, driven by reduced dry-season freshwater flows, sea level rise, and shrimp farming. Rice yields in affected districts have declined 15-25%, threatening food security for a nation dependent on domestic rice production.
• Climate-driven megacity pressure: An estimated 300,000-400,000 people migrate to Dhaka annually, creating compounding urban vulnerability. Dhaka's drainage, water supply, and housing infrastructure cannot absorb climate migration at this rate without transformative investment.

Three policy priorities:

• Accelerate Delta Plan 2100 implementation: The $37 billion, 30-year investment plan integrates flood defence, drainage, freshwater retention, and salinity management. Front-loading investment in critical coastal embankment upgrades and polder rehabilitation would yield immediate returns in reduced flood damage.
• Lead the Loss and Damage coalition with a concrete financing proposal: Bangladesh's moral authority as a low-emitting, high-vulnerability nation positions it to shape the operationalization of the Loss and Damage Fund. Demanding innovative financing mechanisms (fossil fuel extraction levies, international shipping emissions charges, financial transaction taxes) that match the scale of actual losses is essential.
• Climate-proof critical infrastructure: Systematically upgrade the 5,017 km coastal embankment system, many segments dating to the 1960s-1980s and not designed for current sea level conditions. Combine engineered defences with nature-based solutions, particularly mangrove restoration as bio-shields for the coastal population.

Data sources: World Bank Development Indicators, Global Climate Risk Index (Germanwatch), IPCC AR6, ND-GAIN, Bangladesh Meteorological Department, CEGIS, Bangladesh Water Development Board, MoEFCC Bangladesh, IOM Migration Data Portal.