KOTZEBUE, Alaska (AP):

President Barack Obama crossed the Arctic Circle yesterday in a first by a sitting US president, telling residents in a far-flung Alaska village that their plight should be the world's wake-up call on global warming.

Obama's visit to Kotzebue, a town of some 3,000 people in the Alaska Arctic, was designed to snap the country to attention by illustrating the ways warmer temperatures have already threatened entire communities and ways of life in Alaska. He said, despite progress in reducing greenhouse gases, the planet is already warming and the US isn't doing enough to stop it.

"I've been trying to make the rest of the country more aware of a changing climate, but you're already living it," Obama told a crowd of more than 1,000 in this rough-and-tumble town on Alaska's western coast.

Immense challenges

As he closed out a three-day tour of the state focused almost entirely on climate change, the president sought to show solidarity with Alaska natives and rural Alaskans whose immense challenges are rarely in the national spotlight. His brief visit had the feeling of a campaign rally, with throngs of people cheering and applauding when he invoked the historic nature of the first presidential visit to the Arctic.

From the moment Air Force One touched down in Kotzebue, examples of dire poverty and climate-related obstacles were easy to spot. Obama's motorcade snaked through the town passing rows of rusting shipping containers and dilapidated huts - almost all on stilts to accommodate gusts of wind and other weather-related events.

Despite poverty

It was a topic Obama brought up, by way of praising Alaskans for their perseverance despite poverty, isolation and a lack of support. He said while many speak of America's pioneering, independent spirit, in Alaska it's not just a slogan but a way of life.

"It can be harsh," Obama said. "That means that you depend on each other."

Obama came to Alaska with no grand policy pronouncements or promises of massive federal aid. Instead, he sought to use the changes to Alaska's breathtaking landscape to put pressure on leaders in the US and abroad to cut greenhouse gas emissions, as he works to secure a global climate treaty that he hopes will form a cornerstone of his environmental legacy.