The birth of Bangladesh: How the Bhola cyclone fostered revolution

Did one of history’s deadliest natural disasters help shape the birth of Bangladesh?

In this episode of Economics Unpacked, Mushfiq Mobarak explores the role of the 1970 Bhola cyclone in shaping Bangladesh’s independence.

Drawing on historical satellite imagery, archival records, and modern economic analysis, this research examines how the cyclone affected voting behaviour, support for the Awami League, and participation in the 1971 Liberation War. It also highlights how government responses to natural disasters can influence political stability, conflict, and public trust.

The findings suggest that while the cyclone alone did not determine Bangladesh’s independence, it strengthened support for the independence movement and increased participation in the war effort – offering important lessons for governments responding to today’s increasingly frequent and severe climate shocks.

Transcript

Do climate shocks affect politics? We are going to use historical data from my country, Bangladesh, to shed light on this question by studying the 1970 Bhola cyclone, one of the deadliest natural disasters in history. In 1971, Bangladesh ultimately won its independence. The creation of the eighth most populous nation in the world, Bangladesh, was one of the most important events of the 20th century. The question we ask is: was the cyclone pivotal to the birth of Bangladesh?

Welcome to Economics Unpacked, a VoxDev series. My name is Mushfiq Mobarak, and I’m a professor of economics at Yale University. A paper published in the journal Nature logs about 145 separate cases of separatist movements during the 20th century, and only 27 of them succeeded in achieving their primary objective of leading to some kind of separatist state.

When we look at this history of separatism – whether it’s Croatia’s independence from Serbia and Yugoslavia, or Irish independence from Great Britain – what you see is that it requires two critical steps. The first is that there has to be some kind of event that allows people to unify their voices and express their desire for separatism. The second step is people being willing to risk their own lives and take up arms against an incumbent government. At this step, a lot of these separatist movements fail. Some examples of this are the Tamil Eelam movement in Sri Lanka, which led to a 27-year civil war in Sri Lanka, and ultimately Sri Lanka remained intact, and the Tamils in northern Sri Lanka never got their own state. Another example is Biafra in the 1960s in Nigeria, which led to a two-and-a-half-year civil war in Nigeria, but ultimately Nigeria remained intact.

The fundamental question we’re asking in our research is whether a climate shock can change either or both of those conditions that lead to a successful independence movement.

I was born and raised in Bangladesh, so I grew up with these stories of our independence, and this particular history was taught in school textbooks. This is an event that has been studied extensively by the other social sciences, like history and political science, using qualitative methods. It’s an important event that just hasn’t received much attention from economists using their quantitative toolkit. So I wanted to understand the history better, and understand what were the critical factors that allowed for this separatist movement to turn into an independent nation. Together with Sultan Mahmud, we take the toolkit of economics to look at this moment in history.

Tumultuous crowds fill the streets, celebrating, singing and laughing. It’s Karachi’s first day of independence. After the British left the Indian subcontinent, Muslim-majority areas were put together as a new nation state of Pakistan. It had two provinces: West Pakistan, which is now known as Pakistan, and East Pakistan, which is now known as Bangladesh. These two provinces were separated by a thousand miles of India, a non-friendly state in between. There was really not much in common between the eastern and western provinces of Pakistan except for the same religion. The culture, the ethnicity, the language, the economies were quite different from each other. The centre of power always remained in West Pakistan, in Islamabad, the capital.

In 1952, Muhammad Ali Jinnah, known as the father of Pakistan, announced that Urdu, the language of West Pakistan, and Urdu alone, would be the unified language of all of Pakistan. There was a revolt centred around Dhaka University campus, where students came out into the street to protest this decision. So basically, our war for independence started almost 20 years before we actually got independence, and it started as a language movement. After that, the other grievances that accumulated were more economic in nature. East Pakistan accounted for about two-thirds of all the population of Pakistan, but it received only 29% of government revenue.

Then, in 1970, the first elections in Pakistan in about 16 years were scheduled for December 1970, and there was a party in East Pakistan called the Awami League, led by Sheikh Mujibur Rahman, who later becomes the founder of Bangladesh, or the father of Bangladesh. It was really a movement for separatism, not full independence. Now, what changed was this cyclone that happened just a month before the elections, and that hit the coast of Bengal – which remains the cyclone that has caused the largest number of human deaths in recorded history. There was no advance warning, and so people had not evacuated that area, and it killed an estimated 350,000 to 500,000 people.

Many of the deaths were, of course, from the initial storm surge. But given the lack of state response and lack of relief, a lot of the deaths actually occurred after the fact, through disease such as cholera outbreaks, etc. The president at the time, Yahya Khan, did not visit the cyclone-affected areas immediately after. He was distracted with some diplomacy between President Nixon of the United States and Chairman Mao. So he stopped by Dhaka on the way back from a trip from Beijing, and then did a helicopter flyby over the cyclone-affected areas, where waterways were full of dead bodies, dead animals. The stench was overpowering, and against that backdrop, Yahya Khan is reported to have said, “Ah, it doesn’t look too bad,” and just flew back to Dhaka because somebody was organising a party.

So all of this meant that it became clear to Bengali, East Pakistan citizens, that this is a government that just didn’t seem to care. Those separatist sentiments that were pre-existing crystallised into an independence movement. The first step of that was to show up at the polls, and then what happens in those polls is that the Awami League actually wins the majority of all seats when you combine across East and West Pakistan, which meant that the military government was supposed to hand over power to the Awami League. But instead, under the guise of some negotiations, they fly Sheikh Mujibur Rahman, the leader of the Awami League, over to West Pakistan. Then they jail him, and then, on the night of 25 March 1971, they start something called Operation Searchlight, which was just basically starting to shoot people in East Pakistan. On 26 March, we declare independence, and the state of Bangladesh is formed.

There was a nine-month period of guerrilla warfare. Young men took up arms, and many of them were receiving the arms from neighbouring India, which was faced with a huge refugee crisis, with Bengalis pouring across the border. Faced with this overwhelming refugee outflow, the Indian military joined the war effort in early summer 1971, and once India joined, within a few days it became clear the war was over, and then the Pakistan military was going to surrender. The victory day we celebrate is 16 December 1971.

So Bangladesh appears to satisfy the two criteria for a successful separatist movement. But how do we prove that the cyclone was actually the inciting incident? To use quantitative methods and large-sample data to answer a question like this, the first thing you need is variation – variation in, say, the intensity of the cyclone as experienced by different people living in different parts of the country, and then variation in whether those different people reacted differently, given how exposed they were to this climate shock.

To understand this, we actually had to dig through and got very lucky with historical satellite data and other archival sources that we had to digitise. The first bit of good luck was that there was a satellite put into orbit by the US Department of Defense in January 1970. This was the world’s first satellite with a geosynchronous orbit, so it could take pictures constantly. This ITOS-1 satellite was put out of commission in mid-November 1970, due to a tape recorder malfunction. But we got extremely lucky, because the cyclone takes place a few days before the satellite goes out of commission. And then, recently, there have been some developments in physics and meteorology research that allow us to translate those images into a prediction about the cyclone’s intensity.

The general idea is that if there is very thick cloud cover, which is very correlated with how strong the winds were – the thickness of the cloud cover might prevent solar radiation from reaching the ground, and the images can actually measure that solar radiation as well. So, using an algorithm that translates the solar radiation and cloud cover into wind speeds, we are able to back out how intense the winds must have been in different parts of the country, or the province of East Pakistan. That meant that there were some districts, some political constituencies, that experienced the devastation in a much more intense way than others, and that is the variation that we end up using.

So we’re asking the question: did the people who experienced the cyclone more intensely vote differently a month later, in those December 1970 elections? And we also asked the question: were the people in the constituencies where they experienced the cyclone more intensely the ones more willing to take up arms and become guerrilla fighters, fighting against the Pakistan military about three months later?

We find that those constituencies that experienced the cyclone more intensely are more likely to vote for the separatist party, the Awami League. In those areas, the Awami League’s vote share increases from about 74 to 77%. We also see that these same constituencies that experienced the cyclone more intensely supplied more of the guerrilla fighters, or freedom fighters. So, when we look at the archival records of the birthplaces of the freedom fighters, we see that cyclone-affected areas are over-represented in those birthplaces. When you aggregate across the entire province, we estimate that there were an additional 46,000 fighters who joined the war effort as a result of experiencing a more intense cyclone.

Going back to the main question of whether this cyclone, or a climate shock, is pivotal to ensuring that a separatist movement successfully creates a new nation state. I think the first step, where we see the Awami League’s vote share increasing from 74 to 77%, makes it not very plausible that the cyclone itself was a pivotal event that made the difference between an independent Bangladesh versus not. The reason is that the Awami League was already quite popular, so they would have won the election anyway. They did win by a bigger margin due to the cyclone. However, the fact that the cyclone induced more people to join the war effort, and held off the Pakistan army, could have made a critical difference.

Can this research conclusively prove that the cyclone was the cause of Bangladesh’s independence? No, it cannot. What we show is that it did shift the balance, first politically, and then in terms of conflict participation, in the direction of people expressing their anger, both in the polls and on the battlefield. Some of those factors may have been critical. So what our research shows is that climate shocks not only cause these environmental and economic harms, but they may also have broader economic and conflict impacts as well.

Our research allows us to connect the dots and paint that picture a little more clearly. And what we learned, by painting the picture more clearly and looking at this precise mechanism, is that it’s not just the shock that matters – it’s also the government’s responsiveness to the shock, whether they choose to respond with relief for people who were affected, versus whether they ignore those shocks.

So, looking to the future, we are in a world where climate shocks are becoming more severe and more frequent. We are seeing more extreme weather events – more hurricanes, more typhoons, and cyclones – all over the world. What we need to understand is how governments should respond to these types of weather events in order to address citizen concerns. Maybe that will help give us guidance on what types of responsiveness to climate shocks we need, such that we can prevent more of these large-scale conflicts that cause a lot of unnecessary death and destruction.

If you like this video, please like and subscribe. And for more information about this research with Sultan Mahmud, check out the links below.