Espen Finstad was trudging through mud in the Jotunheimen mountains of eastern Norway this month when he happened upon a wooden arrow, bound with a pointed tip made of quartzite. Complete with feathers, it was so well-preserved that it looked as if it could have been lost just recently.

But Mr. Finstad, a glacial archaeologist for the county of Innlandet, knew better. By his estimate, the arrow is probably about 3,000 years old.

“I was really excited,” he said. “I’ve never seen something like this before because it was so complete.”

The find, which Mr. Finstad and his colleagues believe belonged to a reindeer hunter in the late Stone Age or early Bronze Age, is among thousands of artifacts and remains that have emerged from melting ice in recent years, as climate change thaws permafrost and glaciers around the world.

Last month, the global surface temperature was 1.25 degrees Celsius above the 20th century average, making it the planet’s warmest August on record, according to the National Oceanic and Atmospheric Administration. That heat is rapidly melting the ice, from the American West to Kilimanjaro, the Dolomites and the Himalayan mountains.

The thaw presents a fleeting opportunity for glacial archaeologists: They must find the historical treasures just as they emerge from the ice and before they are destroyed by the elements.

“We’re sort of in a race against time,” said Lars Holger Pilo, a glacial archaeologist and a colleague of Mr. Finstad’s. “We really need to work even harder to save as many of these artifacts as we possibly can.”

For more than a decade, their team, which runs the Secrets of the Ice project, has scoured mountain passes across the country. The project, a cooperative effort between Innlandet County Municipality and the Museum of Cultural History, University of Oslo, was founded in 2011.

Since then, the team has discovered around 4,000 artifacts and remains, including a 1,000-year-old wooden whisk and Viking mitten, medieval horseshoes, Bronze Age skis and more than 150 arrows.

Similar work is taking place near Anchorage, Alaska, as well as in northeastern Siberia and Mongolia.

Among the most exciting finds have been Yuka, a 39,000-year-old baby Mammoth found in Siberia in 2010, and a 280-million-year-old tree fossil found in Antarctica in 2016. But the most famous of all is Ötzi — a 5,300-year-old iceman found in 1991 by hikers on the northern Italian border with Austria.

At first presumed to be an unlucky mountaineer, Ötzi was later determined to be a Copper Age fellow, making him the most well-preserved mummy in history. He has since shed light on the social bonds, diets and lives of Copper Age humans.

“We are always hoping for an ice mummy,” Dr. Pilo said. “But, of course, the chances of that are really small.”

For now, he and his colleagues are content with the 250 or so objects pulled this year from the melted sludge in Norway, including a Viking Age knife, an iron horse bit, and several arrows, including the 3,000-year-old artifact.

What makes the arrow so impressive, Mr. Finstad said, is its preservation: Though it is broken into three parts, the arrowhead remains attached to the shaft, as do the feathers, known as fletchings, which help to stabilize the arrow’s flight path. Once the scientists carbon date the arrow, they can determine its exact age.

William Taylor, an associate professor of archaeology at the University of Colorado, Boulder, who was not involved in the Norwegian field research, said the “incredible” thing about the near-intact arrow was that it helped to fill in gaps about how such objects were made and used.

“We’re often sort of guessing at the big picture from whatever was robust enough to weather through the centuries,” said Dr. Taylor, who conducts similar research amid melting ice in Mongolia. The arrow, he added, “leaves nothing to the imagination.”

He noted that the clock was ticking to find objects before they deteriorate.

“This is a discipline that exists almost exclusively because we are in the sort of throes of catastrophic global climate change,” he said.

Mr. Finstad, the Norwegian archaeologist who discovered the arrow, described the finding as among his “top 10” favorites because its near-pristine state had helped him envisage the lives of those who had lived and died in the same mountains.

“You also kind of feel a special connection to the people who lost it,” he said.