While we worry about global warming affecting our future, it will also damage our past. Archaeological sites from the frozen steppes of Central Asia to the coast of Greenland are threatened by climate change.

In the survey Sites in Peril for the Archaeological Institute of the American publication Archaeology, Andrew Curry says that “archaeologists can’t stop global warming but they can make dealing with it a priority”.

One project is to save frozen tombs in the Altai Mountains of Kazakhstan and Russia, which in the past 60 years have yielded burials with well-preserved grave goods. Many have been frozen for more than two millennia, sandwiched between frozen subsoil and the insulating mound of rubble above which forms a kurgan, similar to the round barrows of Salisbury Plain in appearance. The bodies have been mummified by the cold, and their clothing, often with elaborate appliqué designs, and stomach contents have been preserved intact.

“The material is so well preserved it’s almost a kind of ethnography instead of archaeology,” says Hermann Parzinger, of the Prussian Cultural Heritage Foundation, after excavating the tomb of a Scythian warrior three years ago.

The problem, Curry says, is that the Altai is warming, the glaciers shrinking, and “for the first time since their occupants were buried 3,000 years ago, the Scythian tombs are in danger of thawing out and rotting away”. Jean Bourgeois, of the University of Ghent, notes that just a degree or two can be enough to destroy the frozen contents of the kurgans. He hopes to find ways to keep temperatures down: possibilities include painting the kurgans white to reflect sunlight away, and installing underground “thermo-pumps” to stabilise the temperature. The priority is to ascertain which kurgans still have a layer of permafrost below them and might therefore be saved. Others may have to be excavated in an emergency campaign, Curry says.

Glaciers in the Alps are also retreating. In the summer of 2004 the margins of one 5ft-thick ice patch monitored by glaciologists shrank by 20ft in a week. As the ice melted, archaeologists found artefacts in it ranging from prehistoric leather clothing to nails from Roman sandals. Gaps in the dates of the finds coincided with cold periods when the pass, near the Schnidejoch Glacier in Switzerland, would have been blocked by glacial ice.

“The fact that fragile organic materials were preserved for more than 5,000 years means that the ice cover hasn’t been this small since the Stone Age,” Curry says. “For archaeologists, the melting ice is both a crisis and an opportunity.”

It is clear that Ötzi, the famous iceman from the Italian Alps to the east, may be only one of many stunning finds with an equal chance of either discovery or destruction in the next few years.

On the coast of Greenland, the melting of sea ice has stripped away the protective barrier that mitigated shoreline erosion. As a result, villages of the 2,000-year-old Thule culture, with houses built of stone and turf and using whalebones as roof beams, are disappearing rapidly. Bjarne Gronnow, of the National Museum of Copenhagen, estimates that the shore is being cut back by a metre a year. Older sites are endangered as well, he says. Qeqertasussuk, a 4,500-year-old site preserving evidence of the earliest-known settlement of Greenland, is covered by a frozen layer of turf which, Gronnow believes, is now close to melting.

Rising sea levels threaten the evidence for the first settlement of the American continent, on the Channel Islands off the coast of California: coastal rock shelters and middens up to 13,000 years old are being eroded by the waves, Curry reports.

Archaeology 62 No. 2: 32-35.