IN BANGLADESH and the neighboring Indian state
of West Bengal, there are thousands of villages
like East Dhangmari—places that are losing their
natural defenses against climate change just as it
is intensifying. The land is paper-flat and criss-
crossed by rivers bulging with meltwater from
the Himalaya. Cyclones frequently roar in off
the Bay of Bengal, sometimes killing thousands.
Flooding is pervasive.
Some farmers in Bangladesh—a country the
size of Iowa with a population of 160 million—
refer to their homeland as a divine prank: The
soil is fantastically fertile, but you’re always in
danger of getting washed away. In 1998 an espe-
cially monstrous flood inundated about 70 per-
cent of the country.
One thing the region’s coastal communities
felt they could always bank on, though, is the
Sundarbans, the world’s largest contiguous man-
grove forest. Spanning nearly 4,000 square miles
on both sides of the Indian-Bangladeshi border,
this dense swamp of flood-tolerant trees stands
as a green wall, absorbing storm surges and
blunting even the worst cyclones. For villagers,
the forest is also an abundant source of honey
and its waters a source of fish. “The Sundarbans
is our mother,” said Joydev Sardar, secretary of
the fishermen’s association in Harinagar, Ban-
gladesh. “She protects, feeds, and employs us.”
But after years of abuse from man and nature,
the mangroves seem to be nearing their limits.
Illicit logging, mostly for building materials to
house the region’s booming population, has
thinned out the periphery of the forest. At the
same time, increasing water salinity caused by
the encroaching sea is killing off many higher
value, storm-stopping tree species, such as
the sundari that gives the forest its name. The
salinity assault comes from both land and sea:
Upstream dams on rivers in India have reduced
freshwater flow into the Sundarbans, while sea-
level rise caused by climate change is flushing
more salt water into the mangroves.
“The salinity front is just going up and up
and up,” said Mashfiqus Salehin, a professor
at Bangladesh University of Engineering and
Technology’s Institute of Water and Flood
Management. “New areas will salinize, and
moderately salinized areas might become
unlivable. It’s becoming a big problem.” In the
worst-case scenario, in which sea levels rise by
more than six feet this century, Bangladesh
alone stands to lose some 800 square miles of
mangroves in the Sundarbans. The best-case
scenario is a loss of roughly 80 square miles.
Salehin and other scientists fear even that much
might prove disastrous for a country so poor the
forest is besieged by human needs.
The land itself is disappearing. Without the
tangled roots of the mangroves to stabilize it,
land erodes into the sea—and with upstream
dams trapping river sediment, it’s not replen-
ished as it once was.
The islands in India’s Hugli River, in the Gan-
ges estuary on the western edge of the Sundar-
bans region, illustrate advanced stages of the
decay. At least three islands that a century ago
were covered in mangroves—Lohachahara,
Suparibhanga, and Bedford—have vanished.
Others are eroding fast: Sagar Island has shrunk
by about 20 square miles since the mid-20th
century, even as its population has swollen with
new arrivals from its disappearing neighbors.
Crop-growing conditions on Sagar have deterio-
rated so much that residents now survive largely
off seasonal labor elsewhere.
In some parts of the Sundarbans, the sea is
advancing about 200 yards a year. “The peo-
ple around the Sundarbans will lose a lot,” said
Tuhin Ghosh, an associate professor at Jadavpur
University in Kolkata. “This is happening now.”
But even cities like Kolkata and Dhaka that lie
some distance from the vanishing mangroves, he
added, will find themselves “extremely exposed
to cyclones and storm surges.”
IN FEBRUARY 2018 part of the embankment
that holds back the Chunar River west of East
Dhangmari, Bangladesh, collapsed for the third
time in a year. Sixteen houses were swept away
in what for locals had become an almost rou-
tine tragedy. But as the catalog of misfortunes
mounted over the following months, even the
oldest, most judicious residents knew these
were no ordinary crises. Rice yields during
the 2018 dry-season harvest were way down—
often well under a ton an acre, which pushed up
food prices. In many fields, vegetables simply
wouldn’t grow in the salty soils.
“Because of the water damage, it sometimes
seems like only the carpenters have work,” said
farmer Bimol Sardar.
In the spring of 2018, a disease that has
Funding for this story was provided by Internews’
Earth Journalism Network.
140 NATIONAL GEOGRAPHIC