Today, blueberry bushes drenched in the greens of spring or aflame with the colors of autumn blanket the ridges of Maine’s Down East region.

But somewhere between 23,000 and 28,000 years ago, when a mile-deep mountain of ice was beginning the long, slow retreat that would mark the end of a glacial period in Maine, the frigid coast was no Vacationland.

The very hills that give blueberry country its well-drained, sandy soil were once glacial moraines – moatlike deposits of sand and gravel that formed as water rushed from the melting glacier.

Sediment samples and other data reveal that Maine’s climate at the time probably resembled far northern Canada or portions of Greenland that are today within the Arctic Circle.

Glaciers shaped the state of Maine, covering every inch of its land and weighing down the surface so much so that when the ice rapidly melted, seawater flooded in, following the Penobscot River valley as far north and east as Millinocket.

In Maine, the signs of glaciation are all around, from Acadia’s famed Bubble Rock – an orphan boulder known as a “glacial erratic” that was dropped by the ice as it passed over South Bubble Mountain – to the Great Basin of Mount Katahdin itself, shaped by the glaciers that once nestled into its valleys.

Harold “Hal” Borns, founder of the University of Maine’s Climate Change Institute, has spent his life studying the geological signals of glaciers and is amazed at how little people know about the catastrophic climate shift that shaped their state.

“[Mainers] live and die on this landscape, and most of it is glacial,” he said.

Borns is creating an Ice Age Trail, a journey across coastal Maine with glacial clues as its signposts. The trail winds through Hancock and Washington counties highlighting some of the most accessible features that were sculpted into the landscape by tons of moving ice. The trail includes Cadillac Mountain – the first land to emerge from the ice as it made its final retreat – and continues east across the land where glaciers once met the sea. Between 12,000 and 17,000 years ago, the glaciers were gone from Maine, but their footprints remain.

For tens of thousands of years, ice was on the move, seasonally advancing and retreating as it slowly receded, all the while scraping bedrock, dropping boulders and hollowing out lakes. The first Ice Age Trail map will focus on the moraines of coastal Maine, where the ice sheet made its last stand. Borns hopes eventually to expand the trail to the entire state of Maine.

“There are spectacular examples of just about everything … eskers, moraines, deltas, erratics [throughout the state],” said Woodrow Thompson, a geologist with the Maine Geological Survey.

Climate change doesn’t just affect the weather and it doesn’t just change the habitat for plants and animals. When mountains of ice scrape across Earth, climate change has the power to alter the very landscape.

Borns likes to use a three-dimensional map of Maine’s landscape to explain the recession of glaciers across the state over thousands of years.

“There’s a climate change right there,” Borns said, pointing to a long ridge near Addison that clearly shows one of the moraines that crisscross Washington County.

Wisconsin offers tourists the National Ice Age Trail, while Washington is considering a trail to educate people about the glacial origins of the Cascades region. Borns and his colleagues have spent decades mapping glacial footprints on Maine’s landscape. “So why not a trail here?” he asked himself.

“We’ve got all the science done. All we’ve got to do is put it together in a map,” Borns said.

With federal funding, Borns has been working on the project for several years and he hopes to make available by this spring a printed map of a driving route between glacial features along the coast. He already shares considerable information about some of the locations in an interactive map online at: http://iceagetrail.umaine.edu.