SINYAKA ISLAND, Chad — There's nothing remarkable about this lump of hot sand, tangled weeds and tree-branch huts except that, until a few years ago, it didn't exist.
More precisely, the island was underwater, hidden beneath the vast surface of central Africa's Lake Chad. The emergence of the island, whose sweltering shores have been settled by dozens of families, is evidence of an unsettling ecological trend: The lake is drying up.
Once among the largest lakes in the world — at some 9,000 square miles, roughly the size of New Jersey — Lake Chad has been decimated over the past four decades by rising temperatures, diminishing rainfall and a growing population that's using more water than ever before. Today, estimated at less than 2 percent of its original size, the lake's surface would barely cover Brooklyn and Manhattan.
In the dust bowl of western Chad, where the lake used to be deepest, water levels have dropped so low that several new islands have cropped up. Fishermen report that fish stocks are depleted. Much of the lake is a dull gray-blue marshland, dotted by wild clumps of grass and shallow enough to wade through.
Although never very deep — its greatest recorded depth was only 39 feet — the changes are so dramatic that the United Nations Environmental Program called Lake Chad "a ghost of its former self" in a 2006 report.
Its disappearance is another sign of the impact of global warming and population growth, and an ominous development for the lake basin's 30 million inhabitants. The basin, the third largest in Africa, straddles parts of seven countries and, even in better times, includes some of the most forbidding terrain on the continent.
Scientists say a diverse ecosystem that thrived despite the harsh environment — including birds such as the European white stork, which stop here on their annual trans-Sahara migration — is deeply imperiled.
"We have never seen the lake as shallow as this," said Moussa Bana, a 40-year-old fisherman who settled on Sinyaka two years ago and who trawls the lake every day for increasingly rare catches.
The situation is grave enough that it warranted a visit last year by U.N. Secretary-General Ban Ki-moon, who called for a major international effort to save the lake. Earlier this year, four of the countries that make up the lake basin — Cameroon, Chad, Niger and Nigeria — said they were studying a proposal to pump water into the lake from the Oubangui River in Congo, more than 600 miles to the south, at a cost of perhaps hundreds of millions of dollars.
For the four largely poor countries, which struggle to feed their people, the proposal is, at best, ambitious. Environmentalists say the lake may not recover without it, however.
"It's an extreme solution, but unless global hydrology changes tomorrow, this project is the last hope for the lake," said Lambert Tam, the assistant head of the five-country Lake Chad Basin Commission, who works in the Chadian capital, N'Djamena.
Researchers trace the lake's decline to the late 1960s, when rainfall levels began to drop across the western Sahel, the semi-arid belt of land just south of the Sahara. Around the same time, the population of the lake region started a precipitous rise, doubling to 26 million from 1960 to 1990 and sharply increasing the demand for water among pastoralists and farmers.
In decades past, the lake has rebounded naturally from climactic shocks. But the impact of global warming and the population boom together pose a much greater risk.
"If rain would ever come, we might have a chance," said Bana, the fisherman.
On a recent afternoon on Sinyaka, he reclined on a thin mat along with several other tired-looking fishermen, cutting a raffish figure in sunglasses and a turban wrapped loosely to protect him from the harsh sun. Many of the men were Bana's brothers, half-brothers and cousins, members of an extended family of more than 200 that settled the island starting four years ago.
They'd been living in a village on the Chadian mainland, Bana said, until too many fishermen began crowding the shores, competing for fewer and fewer fish. Nomads from northern Niger also began bringing their cattle to the lakeshore to graze, eating up the vegetation and spilling sediment into the lake.
An uncle of his named the island Sinyaka, from an Arabic word meaning "sand," Bana said.
They're alone on this treeless atoll, where there's no cell phone network, no potable water and little cover from the sunlight. The nearest town is a two-hour boat ride away.
Even out here, the fishermen have heard of the proposal to replenish the lake. Asked about its chances, Bana laughed dryly.
"We have heard and heard of such ideas for years," he said.