After Unprecedented Heatwaves,  Monsoon Rains and the Worst Floods in Over a Century Devastate South Asia

KARACHI—Record breaking torrential downpours killed at least 14 people, inundated roads, caused long power outages and brought Pakistan’s largest metropolis to a standstill twice last month. 

Earlier in July, the Indian central government declared flooding in the northeastern state of Assam a “severe natural calamity,” affecting 10,000 people, as torrential rains killed 14 in the state of Gujarat and 16 more died after a flash flood in the Amarnath region. 

But the worst hit so far has been Bangladesh, where more than 7.2 million people have been severely affected by the worst floods in the country in over a century, which experts say were worsened by climate change. 

In late May, more than 10 villages in Bangladesh’s Sylhet and Sunamganj districts flooded after heavy rainfall upstream in northeast India’s Meghalaya region. By May 18, local news reported that road connections in the area had disintegrated, leaving more than 200,000 people stranded. Currently, around 20,000 people are living in more than 275 shelters across the region, according to the United Nations. 

An Uncharacteristically Erratic Monsoon

Floods caused by heavy rainfall in India and Bangladesh’s northeastern region are not uncommon, but the 2022 monsoons were unprecedented and uncharacteristic.

The Indian monsoon, one of the most prominent monsoon systems in the world, which affects India and parts of Bangladesh, develops through a series of complex events that involve changing wind patterns in the Arabian Sea and the Bay of Bengal. Every year in early June, winds from the Arabian Sea push rainclouds over the southern coasts of India, marking the beginning of the summer monsoon that lasts until September and brings the Indian subcontinent more than 70 percent of its annual rainfall. 

As the monsoon develops over India’s southwestern region, winds from the east push rain clouds over the Indo-Gangetic Plain, land comprising the floodplains of the Indus and the Ganga-Brahmaputra rivers and stretching across northern and eastern India, eastern Pakistan, Bangladesh and southern Nepal. 

But this year wind systems that have historically occurred during different periods in the monsoon season coincided to push rain clouds over the northeastern region of India. According to a recent study by Roxy Koll, lead author of the Intergovernmental Panel on Climate Change’s Sixth Assessment and a climate scientist at the Indian Institute of Tropical Meteorology, monsoon winds over the Arabian Sea are exhibiting fluctuating behaviors, “driving surges of moisture supply, leading to extreme rain episodes across the entire central Indian belt.” 

On June 17, Mawsynram, a village in India’s Meghalaya district that is known as one of the wettest places on earth, received 39.51 inches of rain. Cherrapunji, a neighboring city in the region, where annual rainfall is 447.22 inches, received 38.2 inches—approximately 8.5 percent of its yearly rain—in one day, according to data from the Indian Meteorological Department. 

Not only did the region receive heavier than usual rainfall, the summer monsoon, which usually begins in the first week of June and lasts until September, came much earlier. “Bangladesh is one of the champions in disaster management, but it was caught off guard,” said Mrityunjoy Das, senior programme coordinator for humanitarian aid and resilience at CARE.  

The Indian Ocean is one of the fastest warming oceans in the world, with surface temperatures warming by 1 degree Celsius, compared to the global average of 0.7 degrees, according to a report, “Assessment of climate change over the Indian region,”  published by the Ministry of Earth Sciences in India. In addition to the rise in sea surface temperatures, the frequency and intensity of extreme warming events, called marine heatwaves, in the Indian Ocean have increased significantly. A recent study found that the western Indian Ocean and the Bay of Bengal experienced the largest increase in marine heatwaves per decade. “There is an enhancement of monsoon rainfall over southwest India due to the MHWs in the Bay of Bengal,” the report said.  

But an enhanced monsoon does not mean a well spread out monsoon. “Microclimatic changes are being triggered,” said Abinash Mohanty, programme lead for risks and adaptation at the Council on Energy, Environment and Water, a nonprofit policy research institute in New Delhi. As rainfall becomes more sudden and “erratic beyond threshold limits,” dry days across the region are also increasing. For South Asia, this means fewer rainfall days on average but an increase in frequency of record rainfall days and cloud bursts, and consequent flooding. “South Asian countries also have a high population density. So the number of people affected per square kilometer is always high,” said Mohanty.

Bangladesh, a low-lying delta and one of the most densely populated countries in the world, is highly vulnerable to climate change impacts, especially floods and cyclones. According to a 2018 report published by the U.S. Agency for International Development,  33 percent of Bangladesh’s population faces very high climate exposure. Globally, this number is 6 percent. It is the seventh most climate vulnerable country, according to the 2021 Global Climate Risk Index published by Germanwatch, a nonprofit environmental think tank based in Berlin. Between 2000-2019, Bangladesh ranked 9th in annual climate-related fatalities among the 180 countries analyzed in the report, but a network of cyclone shelters, early warning systems and efficient disaster management have helped reduce cyclone-related mortality in the country from 500,000 in 1970 to 4,234 in 2007. 

Every year heavy rainfall and consequent flooding can impact up to a million people in different parts of Bangladesh. But the impact of the 2022 floods has been catastrophic, causing over 100 deaths, and destroying paddy fields, fish ponds and livestock. “Seventy-five thousand hectres of paddy and 300,000 hectares of other crops, including maize and vegetables critical to the population’s nutrition, have been damaged,” said Islam. 

More than 1.2 million people in the country remain in need of key humanitarian assistance, after which aid organizations will begin a “recovery response” that will last at least a year and cost $58 million. On July 14, the United Nations Central Emergency Response Fund allocated $5 million for flood relief in the country, bringing the total available funding to $12 million—20 percent of what the agency has identified as needed. 

But in the face of frequent extreme weather events, erratic monsoons and heightened climate vulnerability, emergency response funds are not enough. According to a 2019 report published by International Institute for Environment and Development, rural households in Bangladesh that are directly and disproportionately impacted by climate change are currently spending almost $2 billion—more than twelve times the international aid the country receives for climate change mitigation—every year on preparing for climate change impacts and repairing old and existing damages. 

“The losses and damages from recurrent cyclones are accumulating and beyond our adaptation limits,” said Islam. Bangladesh could be at risk of losing 2 to 9 percent of its gross domestic product due to climate change by the end of the century, the IPCC’s Sixth Assessment said. 

But while it has been hit the hardest by floods this year, Bangladesh is not alone. Flash floods and urban flooding caused by heavy rainfall have taken lives and extensively damaged property in India and Pakistan as well. 

By late June, more than 5 million people in India’s northeastern state of Assam were impacted by some of the heaviest rains in over a century. According to the state’s disaster management authority, more than 2,500 villages and over 1 million hectares of agricultural land have suffered extensive damage. Presently more than 44 villages in the state are still under water. According to a study published in 2021, with the current adaptation measures in place, it could take the state approximately 900 years to fully protect itself from flood impacts. 

In Pakistan, a month and a half of monsoon rains have killed more than 400 people. In Balochistan, the country’s southwestern province, heavy rains and floods have killed 127 people and washed away more than 9000 houses. Last month flash floods swept away more than 50 homes in the upper Kohistan district in Pakistan’s northwestern province of Khyber Pakhtunkhwa that borders Afghanistan,  according to the country’s national disaster management authority. 

Every year South Asian countries experience heavy monsoon rains that affect thousands of people. A lack of waste management, which results in clogging of sewer systems, and road construction across floodplains, “negatively impact the natural drainage system,” Islam said. A cross-border problem exacerbates flood impacts across the Indian subcontinent. Karachi, one of Pakistan’s largest and most populous cities, is highly vulnerable to climate-related disasters, given its weak infrastructure, the World Bank has said. 

Stormwater drainage systems are choked with solid waste and often damaged by rapid and unplanned urbanization. Overflow during the monsoon season pushed water into the streets and washed out  roads. In 2020, the city experienced the worst rains recorded in over 90 years, which inundated roads, caused massive traffic jams and left parts of the city inaccessible to aid and relief workers. 

The Indian monsoon has been historically erratic, but the early onset of heavy rainfall this year is still an anomaly. “All these hazards are invariably increased because of global warming,” said Giriraj Amarnath, research group leader for disaster risk management and climate resilience at the International Water Management Institute. But while disaster management is a big piece of the puzzle, experts agree that long-term mitigation and adaptation measures are critical for preventing further loss of life as well as  environmental and economic damage from catastrophic extreme weather events in a part of the world that has contributed comparatively little to global carbon emissions. 

In a recent study published in the Climatic Journal, two Dartmouth scientists quantified the climate damages caused by rich nations to poorer and low-emitting countries. Both the United States and China have individually caused more than $1.8 trillion in climate damages to other countries, the study found. Yet the rollout of climate risk finance for developing countries has been slow. “There is a clear lack of commitment on adaptation funds,” said Amarnath.