YAKUTSK, Russia -- In the icy depths of Siberia, man has prevailed against an inhumanly inhospitable nature for hundreds years. Now it looks as if nature was only teasing and will prove man supremely foolish after all.
The earth is gradually swallowing up this ungainly city of 200,000 people, which was built on ground that seemed permanently frozen. The old wooden houses tilt haphazardly, their once-high window sills resting like drooping chins on the ground. Some of the new six-story concrete apartments have big cracks in them.
"We may be gone in 50 years," said Tatyana A. Botulo, a scientist studying the conditions here. "The permafrost is capricious."
Yakutsk is the capital of Yakutia, 1.2 million square miles of snow and ice, diamonds and gold, where the average temperature is below freezing and where winter is considered mild when it's only 40 below. Forty percent of Yakutia lies above the Arctic Circle, and about 1 million people live here.
Though the old wooden houses handle the permafrost better because they're smaller and more flexible, the Soviet plan called for big, inflexible apartment buildings. So Yakutsk is filled with six- and nine-story buildings built on stilts. The stilts are actually piles that are driven into the ground to rest on the permafrost. All the buildings are a few feet off the ground.
There's one basement in this city, so of course it's a museum. Carefully slip your way down the icy cellar steps and you're over your head in permafrost.
In Russia, anything worth thinking about has its own government institute. This one is the Permafrost Institute, a lonely building near the edge of town where scientists devote themselves to studying the permanently frozen ground under their feet.
At this institute, Mrs. Botulo puzzles over how long her city will last.
"Our most interesting problem is the melting of permafrost," she said. "What will it do? It could disappear or lose depth. And cities constructed on permafrost could be destroyed."
In the summer, the layer above the permafrost melts, turning the mixture of 40 percent water and 60 percent sand into oozing mud. Anything on top sinks and shifts.
To build here, Soviet engineers sank piles 30 feet down, to rest on permanently frozen soil that was hard as granite.
Then they had to solve the problem of the top of the pile defrosting and the bottom staying frozen, which caused too much stress. So they filled the piles with gases to keep a stable temperature throughout.
Now, the very presence of the city is affecting the permafrost. The buildings bring warmth -- relatively speaking -- as does pollution from cars and heating plants. Yakutsk is in a valley on the Lena River, and a frequent fog hangs over it. A global warming trend may be at work as well.
About 6 feet of soil defrosts in the summer -- beginning in May and ending in September. But scientists are worried that the warm layer could increase to 16 feet, making the piles unsteady.
"The houses built last year will be falling apart," Mrs. Botulo said. "Only the wooden houses of the 1950s will last for the next 50 years."
When she opens the basement door at the institute, it's like walking into a large freezer.
"The rocks here are 10,000 to 12,000 years old," Mrs. Botulo said, several flights down. "It's pretty young."
Last winter, 10 bags of snow were piled up at a landing 14 steps down, for later study. They stayed there all summer, without melting.
A monument to a baby mammoth stands outside the institute. He was found in a Yakutia gold mine in 1977, frozen in time.
"He was 6 months old, and he was so thin," Mrs. Botulo said. "He had been there 39,000 years."
Mrs. Botulo said there is some talk of moving the city to the hills, but there also is growing evidence that cities should not have been built here at all.
Towns were built at gold, diamond and coal mines when it might have been more economical to rotate workers in and out. Little grows here, so food has to be flown in. Construction costs are 60 percent higher than elsewhere in Russia.
Gold mines are shutting down because the cost of extracting the precious metal is higher than the world price. One mine has 100 people working, and 1,000 people living there.
Yakutia was lightly settled until the 1950s, when diamonds were discovered. Flocks of young people, inspired by patriotism, came to live in cities like Mirny, west of here, and Udachny, on the Arctic Circle.
"We believed in communism then," said Taisiya Vecherina, the curator of Mirny's museum.
She and her husband answered the call "Diamonds for the Mother land!" and arrived in Mirny in 1959, when it was a few wooden barracks and a sea of tents nearly buried in the snow. "They called on us to build new frontiers. We were romantics."
Once there, it was hard to go back with no job or apartment elsewhere. "We were very dumb and healthy at first," Mrs. Vecherina said, "and then we got used to it."
Lev A. Safonov, now first vice president of the Almazy Rossii-Sakha diamond company in Mirny, arrived there in July 1960. He remembers unpaved roads and a frenzy of construction and years when everyone had to wear high rubber boots all summer because of the mud.
"It was a time for romantics," he said. "It is over and will never return."
But larger-than-life challenges still hold their sway. John E. Emmert, an oil man from Midland, Texas, is in Mirny to build the world's first indoor refinery. Because of the cold, it will be enclosed in a 12-story building.
The refinery itself is being shipped from Texas, in 16 60-foot-high modules, to make fuel for the mining operations.
"It's going to be a job getting some old boys here to put it together," said Mr. Emmert. "Those old boys want their bacon and eggs for breakfast. You can't give them these cucumbers and tomatoes."
Mr. Emmert and his wife settled into the hotel breakfast fare of salami and tomatoes quite agreeably.
" 'Least you don't have to worry about eating rat," he said, "like in Equatorial Guinea."