FUNAFUTI, TUVALU — Palelei Tovia recalls how Tuvalu islanders used to survive droughts with all-night vigils at wells to collect precious fresh water during the moments it seeped into the shafts.
Ms. Tovia, now a school teacher, said that during the last bad drought 14 years ago, she stayed up beside a well with her high school friends, telling each other stories to stay awake. As the ocean tide rose, she said, it would push fresh water up into the well, and they would take turns scooping it out, cup by cup.
This year's drought on this isolated atoll in the South Pacific Ocean is equally severe, she said, but with a difference. People no longer turn to well water when the rains fail. It is too contaminated and salty to drink.
"The situation is bad," said Pusinelli Laafai, Tuvalu's permanent secretary of home affairs. "It's really bad."
Experts say the contamination is caused in part by development and population growth. Part can also be attributed to greater recent tidal fluctuations, resulting in unusually high tides that have mixed salt water in with groundwater.
Tuvalu could become a bellwether for low-lying islands from the Maldives to Kiribati, where rising oceans could threaten to contaminate ground water to the point where it becomes unable to sustain life.
"Clearly one of the issues for all coral atolls is the limited fresh water available," said Ian Fry, a climate lecturer at National University of Australia who also works as an international environmental officer for the Tuvalu government. "It's one of the greatest problems."
For now, Tuvalu islanders are not focused on this potential long-term threat. They are preoccupied with the immediate challenge of providing fresh water to their families.
The atoll of Funafuti is a snaking sliver of coral just 100 yards across in many places and rising no higher than 15 feet. It forms a divide between the ocean and a sparkling lagoon, but it has grown crowded and polluted despite its idyllic backdrop.
A natural weather pattern known as La Nina has settled over the region and deprived Tuvalu of any substantial rainfall for six months. Weather linked to La Nina also has been blamed for the higher tides.
Forecasters say it could be another three months before the rains return.
The situation became so dire that two weeks ago, Tuvalu and neighboring Tokelau each declared a state of emergency. The Red Cross along with the governments of New Zealand, Australia and the United States averted a catastrophe by rushing in supplies of bottled water and desalination plants.
Even this has proved barely enough.
At a convenience store that advertises pig feed and milkshakes, cashier Vihui Nia said the drought makes her consider leaving Tuvalu.
"For my kids, I want to take them to a place where there is plenty of water," she said.
Mrs. Nia lives in a household of 12, typical of the extended families in this nation of 10,000. Under a government rationing system enforced after months of drought, the family is allowed to collect just two buckets of fresh water each day, less than one gallon per person.
Like most others on the island, Mrs. Nia lines up at a collection point each morning between 6 a.m. and 8 a.m. to collect her water. She supplements the government ration with the last of the family's rainwater in a catchment tank, but that, too, has almost run dry.
"Sometimes people come in and buy a bottle of water for bathing," she said.
At the Nauti Primary School, Ms. Tovia points to a breadfruit tree just outside her open-air classroom. There are bare branches at the top, falling leaves and no fruit. Usually at this time of year, she said, it is full of the edible fruit upon which islanders rely.
She is also worried about the 22 students in her sixth-grade class.
Starting a few weeks ago, Ms. Tovia said, she noticed that two or three would be absent each day.
"They said, 'We have no water for washing our uniforms,' " she said.
Since then, the government has allowed students to attend schools in regular clothes.
Mr. Laafai, the Tuvalu home affairs official, is candid in acknowledging that government officials were slow to react to a crisis months in the making.
"I guess people were just here not paying much attention," he said. "But we did get an occasional splash of rain, and that made people complacent and sit back."
Mr. Laafai said coconut and fruit trees are dying in addition to the breadfruit.
"Our government has been promoting all these climatic issues in the global arena," he said. "In the long term, we will still be here, I think, and we will try to cope. We'll manage somehow, even if it's difficult and expensive."
Tuvalu's economy relies mainly on the sale of offshore fishing licenses, income from a trust fund established by donor countries, and the leasing of its fortuitous Internet domain name, ".TV".
The New Zealand defense force has helped repair Tuvalu's main desalination unit, which sucks 500 gallons of saltwater from the lagoon each hour and turns it into fresh water. New Zealand has also brought over a large desalination unit to increase capacity.
Nobody sees this as a long-term solution. Mr. Fry, for one, worries about cost.
"It's an energy-using system, and importing fuel is a major drain on the economy," he said.
He believes that to survive here, islanders will need to get better about conserving the water they do have and improve the rooftop rain catchment systems on which most households rely. Even that has its problems, he said.
"Rain is such a random event there," he said. "There's no geographical feature to trap the precipitation going past."
Mr. Fry said the groundwater has become contaminated in part by the waste from humans and pigs living on the island, a situation that may have been exacerbated by giant holes dug in the coral during World War II to provide the fill needed to create an airstrip. High tides have also been making the water salty.
So far, the actual rise in ocean levels has been minimal, he said.