The Honolulu-based Coast Guard cutter Walnut is heading to the islands of Tokelau to deliver much-needed fresh water, a spokesman said today.

The Walnut is in American Samoa on a patrol and is being diverted to Tokelau where crops are wilting, schools have shut their bathrooms, and government officials are bathing in lagoons because of a severe shortage of fresh water.

The island groups of Tuvalu and Tokelau have declared emergencies, relying on bottled water and seeking more desalination machines. Parts of Samoa are starting to ration water.

Supplies are precariously low after a severe lack of rain in a region where underground reserves have been fouled by saltwater from rising seas that scientists have linked to climate change.

The Walnut will pick up water containers and a damage assessment team sent from New Zealand today and deliver 36,000 gallons of drinking water water and the personnel to Tokelau.

Six months of low rainfall have dried out the islands. Climate scientists say it’s part of a cyclical Pacific weather pattern known as La Nina — and they predict the coming months will bring no relief, with the pattern expected to continue.

Rising sea levels are exacerbating the problem, as salt water seeps into underground supplies of fresh water that are drawn to the surface through wells.

On the three main atolls that make up isolated Tokelau, the 1,400 residents ran out of fresh water altogether last week and are relying on a seven-day supply of bottled water that was sent Saturday from Samoa, Suveinakama said.

Suveinakama said that some schools no longer have drinking water available, and that the students often need to return home if they want to use a bathroom.

"In terms of domestic chores, like washing clothes, everything’s been put on hold," he said. "We are cautious of the situation given the possible health issues."

Suveinakama said that Tokelau, a territory of New Zealand, has tapped emergency funds to buy desalination machines, which turn salt water into fresh water. He hopes those will be shipped to the islands soon.

In Tuvalu, a nation of low lying atolls that is home to less than 11,000 people, Red Cross team leader Dean Manderson described the situation as "quite dire."

He said that on the island of Nukulaelae, there were only 16 gallons of fresh water remaining Tuesday for the 350 residents and that the Red Cross was sending over two small desalination machines.

He said much of the well water on Tuvalu is unusable because it has become contaminated with salt water.

The New Zealand government this week flew a defense force C-130 plane to Tuvalu stocked with Red Cross supplies of bottled water and desalination machines. Officials including High Commissioner Gareth Smith also flew over to assess the situation.

Smith said the coconut trees on Tuvalu are looking sickly and that the edible breadfruit, which grow in trees, are much smaller than usual. He said other local fruits and vegetables, including a type of giant taro, are not growing well or are in short supply.

He said people in the capital of Funafuti are permitted a ration of two buckets of water per day and that government ministers have been bathing in the lagoon to preserve water.

Funafuti residents have been relying on a large desalination machine for much of their daily water supply, said Manderson. The Red Cross has been helping improve the function of that machine and has been fixing other such machines that have broken down, he added.

New Zealand climate scientist James Renwick said the rainfall problems can be traced back 12 months, when the region began experiencing one of the strongest La Nina systems on record.

La Nina is sparked when larger-than-normal differences in water temperature across the Pacific Ocean cause the east-blowing trade winds to increase in strength, Renwick said. That, in turn, pushes rainfall to the west, leaving places like Tuvalu and Tokelau dry.

Last year’s La Nina system dwindled by June but has begun picking up again just ahead of the November rainy season, Renwick said, meaning that there is no relief in sight for island groups like Tuvalu, Tokelau and Samoa.

"Low rainfall continues to be on the cards, at least through the end of the year," Renwick said.

Officials say they are concentrating on the short-term supply problems and have not yet had time to think about longer term solutions for the islands. But they say that the combination of rising water levels and low rainfall mean makes life on the islands look increasingly precarious.