Science drowns at land's end | Centre for Science and Environment

Science drowns at land's end

My colleague Pradip Saha has been filming in Ghoramara, an island in the Sunderban delta, to understand why, in this zone suspended between land and water, people talk of nothing but subsidence. Savita’s narration captures the mood. Two years ago, rising water tore into this housewife’s life, taking away her land, source of livelihood and her dignity. She wasn’t compensated. She then moved further landward, paying a landowner to build another home. But now the water’s grasping at her tiny house again: she shows the camera deep gashes in the ground just outside. Every high tide, Savita stays awake, for the water might just pull her under. The land records at the local panchayat office tell it all: the island has shrunk to a handkerchief—from 13,800 ha to 4,290 ha in the last 20 years.

This is not unusual, or new. These are islands located in the river’s mouth as it flows into the Bay of Bengal. Erosion is natural and inevitable. Complete islands have disappeared. Sheikh Lalmohan takes the film crew to a vast stretch of water a little south of Ghoramara. From the boat he points to a corner; his home used to be there. Poignantly, he shows his farm, the school, the temple, a few relatives’ houses—all gone today. Lohachara island, where Lalmohan’s house used to be, went completely under water in the 1980s. Lalmohan now lives in a refugee colony in Sagar island.

Villagers here, well versed with the realities of living in a delta, are more worried today. They sense a change is on them. Till now, when the waters took over, they could move inland or to lands beyond. Now, even the biggest island in the Sunderbans—Sagar—is showing signs of weathering. It is losing land, so much that finding refuge is no longer easy. They can see the pace of erosion is increasing. They cannot measure it in metres; they cannot explain what is happening, but they know they can no longer cope or adapt. They build embankments; they reinforce their mud walls with bamboo barriers. But all is too little and all too late.

The point is to understand this change: is the sea level rising so that land is going under? Has the river’s ecology changed in a way that provokes more erosion? Is the land-sea balance out of kilter? Are all these happening and more?

Even as this reality show was being filmed, off the Bay of Bengal, I happened to be in Goa where the country’s premier oceanography institute is located. The dots needed to be joined. I wanted some answers.

The scientists I met are knowledgeable, but also open about the fact that we are beginning to learn about sea level rise trends along our coast. One way to measure the possible rise of sea level, they explain, is to study the tide gauge records that ports and maritime authorities maintain and analyse trends. Ideally, records of over 60 years are needed. In India, Mumbai port tide gauge data is for 100 years and the rest vary. When scientists A S Unnikrishnan and D Shankar put together all data above 40 years, they got these from 10 ports along the Indian Ocean and Arabian Sea—from Aden in Yemen to Ko Taphao Noi in Thailand. After correction for data inconsistency, they were left with five ports—Aden (where, interestingly, data goes back to the 19th century but ends in 1960), Karachi, Mumbai and Kochi in the Arabian Sea and Visakhapatnam in the Bay of Bengal.

They then plotted this data to look for trends. Firstly, they found there was huge variation in mean sea level—annual and decadal—across the north Indian Ocean. They believed this was primarily due to high intensity wind action as well as growing salinity in the water. Overall, the data revealed sea level rise trends close to the globally observed averages—between 1.06 mm/year to 1.75 mm/year with an average of 1.29 mm/year.

But these averages exclude data from Diamond Harbour in Kolkata and Sagar in Sunderbans because of inconsistency. Here, mean tidal gauge data shows massive changes—5.74 mm/year. Scientists ascribe this increase to the depression of the land around. They cite studies showing land subsidence rates—for tectonic and geological reasons, possibly combined with groundwater extraction—of up to 4 mm/year. In other words, it isn’t only the sea’s level going up but the land level going down.

These are unexplored questions, admits the institute’s director S R Shetye, a leading scientist in the field. The fact is that we have a serious and debilitating lack of human capacity to even understand these Earth changes. The problem, he explains, lies partly in how earth sciences and oceanography are taught. These old professions are the key to the future. But teaching remains out-dated and out of touch. Worse, he says, in India the pedagogy is not connected to the research questions of the day, let alone facilities enabling research. This disjoint has weakened the profession, making the country’s research poor. It needs urgent fixing.

In all this, what does Savita do? She cannot worry about whether the sea is rising or the land is subsiding. It is also clear that climate change is that double whammy (coming on top of all that is already happening) tipping her over. The end result is more erosion; her land will go under again. She has once lost her livelihood and there is no way to ‘adapt’, no way to survive but to move far, very far. Where will she go now?

Is this a glimpse of what the future holds, when the sea does rise at a higher rate, not just in the Sunderbans, but across the populated coasts and islands of the world?

—Sunita Narain

Doha, Qatar
Milan, Italy
Durban, South Africa
New Delhi, India
Cancun, Mexico
Marrakech, Morocco
Copenhagen, Denmark
The Hague, Netherlands
CoP5 Bonn, Germany
Bali, Indonesia
Buenos Aires, Argentina
Nairobi, Kenya
Kyoto, Japan
Montreal, Canada CMP 1
Geneva, Switzerland
Buenos Aires, Argentina
Berlin, Germany

Arjuna Srinidhi
Tel: +011 29955124, 29956394, 29956399
Extn. (307)