MAJULI, India -- Not too long ago, Ganesh Hazarika grew rice, vegetables and peas near the edge of the Brahmaputra River on a small plot that provided him a livelihood and a safety net. Then one day the river took it away. Steadily and mercilessly, it had chewed at the banks until his tiny farm fell into the water.
Landlessness is a rising problem for farmers across India, but Mr. Hazarika's situation is unusual: his plot was located on Majuli, one of the world's largest "inland" islands, an ancient religious center that is home to about 170,000 people and dozens of monasteries. The same river that has encircled the island and sustained it for centuries is now methodically tearing it apart.
"There is nothing permanent here," Mr. Hazarika said on a recent morning, as he stood near a small temple that villagers are planning to move this month as a precaution against erosion. "It changes every year."
For many environmentalists and scientists, the Brahmaputra is a critical laboratory in studying the impact of climate change, with much of the attention focused on the mouth of the river in Bangladesh, where rising waters are expected to radically reorient one of the world's most important estuaries and potentially displace millions of people in the coming decades.
But many miles upstream, the Brahmaputra is also proving difficult to predict or constrain. Seasonal flooding, always a problem, has intensified in recent years in the northeastern Indian state of Assam. Erosion is a concern across Assam, as the huge river regularly shifts course while carrying sand and other sediment from the Himalayas in a simultaneous process of construction and destruction: new sandbars appear even as old, inhabited places are battered by the currents of the river.
Climate change is contributing to these upstream changes, some scientists say, though the Brahmaputra is naturally unstable because of seismic activity and the river's braided shape. The erosion of Majuli has become the most drastic example of the river's ruthless power, and local officials, trying to protect the monasteries and the island's growing population, have responded by building embankments and other protective measures.
"The situation is worsening over time," said D. C. Goswami, a Brahmaputra expert and former head of the department of environmental sciences at Gauhati University. "The measures we are adopting are not able to cope with the problem. We need a more holistic and integrated approach."
Along the southern rim of Majuli, in an area known as Salmara, the Brahmaputra extends to the horizon, seemingly as endless as a churning sea. At its widest, the river can stretch more than 10 miles across. Here, the edge of the island is sheared into a cliff that falls 30 feet to the water, with banana trees floating below, having fallen over the side. Many villagers say they are planning to move deeper into the island this month because of erosion.
"My house fell into the water," said Puna Bhuyan, a hunched farmer in his 70s who was picking mustard seeds recently. He said he had moved three times since 2000. "We are worried about our livelihoods. How can we provide for our families? That uncertainty is always there."
As a braided river -- one that divides into a labyrinth of tributaries and channels -- the Brahmaputra was essentially tossed off its tracks after a major earthquake in 1950. The quake raised the river's floor, increased its load of sediment from the Himalayas and shifted some of the deeper channels so that currents began pounding Majuli.
Arupjyoti Saikia, a historian and expert on the Brahmaputra who teaches at the Indian Institute of Technology, Guwahati, said that Majuli became an island in the 1760s, after a previous earthquake led to new river channels that severed the area from the mainland and, in doing so, isolated a major hub of Assamese culture and religion. Since the 15th century, Majuli has been a center of Vaishnavism, a monotheistic branch of Hinduism centered on the god Vishnu and his avatar Krishna.
Today, there are 36 monasteries, known as satras, yet erosion has forced several of them to relocate within the island. Another 28 monasteries have been moved off the island altogether.
"We believe that if we worship the Brahmaputra and make all the prayer offerings, then the river will not disturb us," said one Vaishnavite priest, Ajit Sharma, as he sat cross-legged in a satra.
In recent years, government officials nominated Majuli as a candidate for World Heritage status under Unesco, though the initial application was returned because of various problems. Laya Madduri, the island's highest ranking civil servant, said local leaders were now trying to organize preservation plans for the remaining satras and also draft a comprehensive conservation plan for the entire island.
Estimating exactly how much erosion has occurred is a matter of debate. Data collected in 1901 suggested that the island was more than 463 square miles; but this figure may have included other surrounding islands and riverbeds. A 2004 academic study concluded that Majuli had eroded to 163 square miles in 2001 from 290 square miles in 1917. And where the island once had 49 named streams in 1917, the number had dropped to 7 by 1972.
"There are other braided rivers in the world," Professor Saikia said. "But because of the earthquake, the river continues to suffer, and to fluctuate. The river is still very, very unstable."
For decades, Assam's state government was charged with protecting the island and responded, primarily, by building embankments. India's national government created a special Brahmaputra Board, which plugged breaches in existing embankments and other structures that are intended to enhance siltation or redirect the river's currents. D. J. Bargohain, the board's chief engineer, says these efforts have actually increased the size of the island by nearly eight square miles since 2004.
"It is not possible to stop erosion completely," he said. "We have lost area in certain parts and gained in other parts."
Some experts are skeptical about that claim, especially since much of the new land is often uninhabitable. Some sandbars have enough vegetation for cattle grazing or for growing mustard seeds, but usually the land that is lost is more productive than the land that is gained. Mr. Goswami, the environmental expert, said it was impossible to gauge the impact of climate change on the island, but he noted that environmental patterns did seem to be shifting in the region.
"We have high floods during the flood times," he said. "And we have dry conditions that are more intense now. The periods of drought and periods of flooding are changing, too."
Along the island's southern rim, people are preparing to move again and build thatch huts atop platforms provided by the local government. Binumai Kalita, 40, lives in a hut that is now less than 75 feet from the island's sheared cliff. Her pumpkin patch extends to the cliff, and five days earlier she watched as a stand of banana trees fell into the river.
"We are afraid," Ms. Kalita said. "We see it in front of our eyes. Ten years ago, this land stretched out another two kilometers," or more than a mile.
Now there is only water.
Hari Kumar and Brian Orland contributed reporting.
This article originally appeared in The New York Times.