No river in Bangladesh within ‘safe operating space’

A recent international study by the University of Glasgow found that none of Bangladesh's rivers remain within the safe operating space (SOS). This groundbreaking research, the first to define SOS for Bangladeshi rivers, focused on minimum water availability in 10 major rivers. 

The study, titled A Safe Operating Space for the Major Rivers in the Bangladesh Delta, highlights the critical environmental challenges facing the country's water systems. It was led by Dr Md Sarwar Hossain, an Associate Professor at the University of Glasgow's School of Social and Environmental Sustainability. 

In a recent interview with The Business Standard, he shared his insights into Bangladesh's river systems and their connection with climate change, sea level rise and salinity in the southwest. 

He shed light on the intricate social-ecological dynamics at play, from the shrinking shrimp industry in the southwestern region to the increasing salinity in the Sundarbans. 

Moreover, the conversation explores the inherent dilemma of achieving Sustainable Development Goals (SDGs), where food security initiatives upstream create water crises and inequality downstream, revealing the urgent need for cross-sectoral and cross-border collaboration to mitigate these pressing challenges.

Dr Md Sarwar Hossain

In your latest research, "A Safe Operating Space for the Major Rivers in the Bangladesh Delta," you found that four out of 10 rivers [Ganges (dry season), Gorai, Halda, and Old Brahmaputra] exceeded the SOS, while the remaining six rivers were given a cautious status. What is the SOS system?

The Safe Operating Space or SOS defines the boundaries within which earth systems can operate safely. We have been analysing data from 10 major rivers over the last 4.5 years following the SOS approach. 

This study was jointly led by the University of Glasgow and Alamgir Kabir from Bangladesh University of Professionals in collaboration with Bangabandhu Sheikh Mujibur Rahman Agricultural University and Riverine People. 

The concept was first introduced in 2009 by Johan Rockstrom, a researcher in Stockholm, to define planetary health. It is about identifying thresholds for earth's systems based on the Holocene state, which is a period characterised by stable temperatures, higher biodiversity, and lower pollution levels. 

For example, for climate change, atmospheric CO₂ concentrations should not exceed 350 parts per million by volume, which has already been exceeded. Transgressing these thresholds has already increased the risk of irreversible climate change, such as sea level rise, drought and food insecurity across the world. 

There are nine planetary processes, including climate, freshwater, river and groundwater flow, environmental pollution and biodiversity. The SOS framework helps determine when we cross these boundaries or exceed safe limits. On a global scale, recent updates show that, except for three, we have already exceeded most of these nine planetary boundaries.

Think of it like standing on the edge of a roof – if you cross the boundary, you will fall. That boundary represents a safe zone. This metaphor applies to planetary health, showing how much we can alter land use or tolerate temperature changes, and how much we have already exceeded these limits. 

In areas like climate change and biodiversity, we are already in the danger zone.

My PhD research (2012-16) at the University of Southampton was focused on the safe operating space. While there has been much research on rivers in Bangladesh, no one has looked at 10 representative rivers on a national or local scale and defined SOS before.

To be more specific, in terms of water, the safe operating space looks at two sides of river flow: drought conditions (not enough water) and flooding (too much water). We didn't study flooding, we focused on whether rivers are receiving the minimum amount of water needed. If we don't get that minimum water, fish populations decrease—not just Hilsha, but other species as well. 

The salinity in the mangrove forests increases, and this isn't just because of rising sea levels. The freshwater flow helps push back seawater intrusion, but without adequate pressure, the balance in the mangroves is disrupted. We are already seeing these impacts in Bangladesh.

So, the significance of minimum water flow is immense. We focused our study on whether the rivers are receiving this minimum water, based on historical data from the last 50-60 years. 

If a river has the minimum water flow, we consider it safe. If not, it's in a dangerous state.

We also used another criterion—if there is at least a 20% hydrological alteration, putting the river closer to danger, we classify it as cautious. Unfortunately, our research found that no river in Bangladesh is currently within a safe operating space.

The reluctance of political regimes across South Asia to take a broader view of human livelihoods and address basic human needs has prevented us from solving the water crisis or adapting to climate change effectively.

What are the reasons for the current state of our rivers?

Our paper identifies several factors, although they are more complementary, as the primary objective of the study was to determine whether the rivers are within a safe operating space. In the policy implications section, based on a literature review, we looked at the drivers behind the condition of each river. 

Some of the key reasons include the construction of barrages, human exploitation of water, hydropower dams and encroachment due to population growth. These factors have all contributed to the rivers not having a safe amount of water. 

On top of these, we also identified siltation, which has been caused by water deprivation, leading to a reduced carrying capacity of the rivers.

One of our reviewers asked about the evidence of the impact of rivers going beyond the safe operating space. We are already seeing it: changes in fish breeding patterns, increased salinity, and rising agricultural costs. These are all interconnected, multi-layered factors. 

Previously, agriculture in our region was heavily dependent on river water, which was much cheaper. But now, with reduced river flow, we rely on groundwater irrigation. When there is not enough natural water flow, farmers need to use more fertilisers, which drives up production costs.

Our rivers have the highest runoff in South Asia, as your study noted, yet we are highly vulnerable in terms of climate change. There are also dams in places in our major river like the Farakka Barrage. How much of the crisis is connected to human-made interventions?

Bangladesh is like a living laboratory for environmental changes happening globally. Because I don't see so many drivers affecting a single country at once. 

It is one of the most vulnerable nations to climate change, yet at the same time, we have one of the highest runoff rates. 

When I talk about Bangladesh, it is hard to make people believe that we have water security issues. Bangladesh is known for heavy monsoon rains, flooding and massive rivers, almost like seas compared to other continents. So, how could water security be a problem here? 

But all these challenges can be traced back to the infrastructure projects built on transboundary rivers in the 1960s and 1970s.

And it is not just about India. If you look at China, Nepal and Pakistan, the situation is similar—everyone has been eager to build hydroelectric dams, starting even before climate change became a major issue in the 19th century. 

Locally, the massive economic activities have contributed to river degradation and pollution. All these factors are interconnected.

The transboundary river problem isn't just ours. For example, if the mangrove forests disappear, it could alter the regional climate patterns across South Asia, severely impacting not only Bangladesh but also India and Nepal. This transboundary water security problem – affecting India, China, Pakistan, Bangladesh and Nepal – is a socio-ecological issue.

Water security is central to achieving the Sustainable Development Goals (SDGs). Without it, enhancing resilience against climate change becomes nearly impossible. How can we adapt to climate change without securing water? It is like throwing coins into a deep sea without knowing what you will get.

So, dams and infrastructure projects are definitely major drivers of the issue, but another factor is the changing rainfall patterns and rising temperatures due to climate change. The reluctance of political regimes across South Asia to take a broader view of human livelihoods and address basic human needs has prevented us from solving the water crisis or adapting to climate change effectively.

You said that the mangroves impact the entire region, and touched upon the intricate relations of different factors building up the system. Can you elaborate?

There are two perspectives. 

First, Bangladesh isn't completely flat – the water current in the Sundarbans area is quite strong due to its geophysical characteristics, which creates pressure from the upstream. The mangroves help maintain a balance between seawater and freshwater, creating a unique environment that requires both. 

But with rising sea levels and increasing salinity, we are not receiving enough fresh water to push back the seawater. As a result, seawater intrusion is accelerating.

If you look at Dhaka, for example, you can see how the degradation of wetlands and the rise in temperatures have happened simultaneously. It is not just global warming causing the heat – local factors are also contributing. 

Wetlands aren't only important for water management, biodiversity and livelihoods; they also regulate the climate. Our analysis shows that in areas where there has been major infrastructural development, temperatures have increased. 

Coming back to the mangroves, they not only protect biodiversity and sustain the livelihoods of those living around them, but in the long term, they play a critical role in regulating the broader ecosystem and climate. 

The water flow, the mangroves and rising sea levels are all interconnected.

Is the increase in salinity in the southwestern belt also connected to barrages built on rivers and reduced freshwater flow?

The core focus of my research is on the social-ecological interactions between water, food and climate from social-ecological systems perspectives and limits to sustainability.

As I said, everything is interconnected, and this interaction is especially complex in southwestern Bangladesh. 

Water flow is certainly a factor but there are other issues at play. One is the transformation of mangrove forests due to human interventions, and another is the construction of polders in coastal areas during the 1960s and 1970s. This creates a difficult trade-off. 

On one hand, without embankments, we can't protect coastal communities from storm surge flooding. On the other hand, these coastal embankments have contributed to increased waterlogging and salinity rise in coastal Bangladesh.

Another factor is shrimp farming, which replaced mangrove forests and agricultural land as salinity levels rose. But now, even shrimp production is declining because of the higher salinity and the spread of diseases. 

If you talk to shrimp farmers, they will tell you that productivity is down, and diseases are up due to the high salinity. At the same time, transforming mangrove areas into shrimp farms has further aggravated the salinity issue.

So, there's no simple answer. The coastal embankment projects, internal land use changes, deforestation, shrimp farming, alterations to the hydrological patterns from upstream, and climate change are all contributing factors. Climate change is essentially adding another layer of complexity to an already challenging situation.

How do barrages, which support food security, also create downstream inequality and water crises, posing a conflict between SDGs?

It is indeed a dilemma and a difficult trade-off. In another of our studies, we demonstrated how many ministries need to collaborate from a system perspective just to achieve food security – ensuring food for all. 

If we tackle issues like food, equality and climate change separately, in isolation, it won't work. These goals need to be synchronized and addressed through collaboration across sectors. Only then can we make meaningful progress on the Sustainable Development Goals