It turns out climate change is revealing more than our failure to curb CO2 emissions: Melting mountain ice caps due to higher global temperatures have in recent years exposed a wealth of previously inaccessible, well-preserved fossils that give us an insight into little known periods of human history. Though climate change has been devastating for our planet, it has been (at least momentarily) generative for archaeology. The field of Glacial Archaeology has taken off in recent decades, with discoveries made from the Swiss Alps to Norway and Canada, the New York Times writes in this survey of the history of the field.

Sounds cool, but isn’t it just like normal archaeology + snow boots? Not exactly. Archaeologists working in this field have basically one month in which to search for findings — between the melting of the winter snow in mid-August and the arrival of the next season’s winter snow in late September. Glacial archaeology involves very little digging, and depends more on surveying the area to see what the ice has exposed. Once a discovery is made, scientists have a very short window — a year at most — in which to study the items before exposure to the elements causes organic materials to degrade. The constant renewal of ice inside glaciers also means that items are rarely preserved for more than 500 years, with ice patches — which are less changing and more stable — being a better location to search for thawed findings.

It is more of a process of working with, rather than drilling through, the ice: Initially, the items revealed dated from the Iron Age, 500-1200 years ago. But as successive winters passed and global warming persisted, the melting ice dissolved with it layers of earth and revealed older findings, from the Bronze Age (1200-3300 BC) and the Stone Age.

Humanity’s oldest (literal) cold case: The star of the field is Otzi, also known as the Iceman. Discovered by a group of hikers in the Otztal mountains in Italy in 1991, the Copper Age mummy was originally thought to be the remains of a mountaineer who had been missing more recently, but carbon dating showed he had lived and died some 5.3k years ago. Covered in tattoos, encased in clothing of animal skin and carrying various tools and herbal medicines, poor Otzi seems to have been murdered while attempting to cross the mountains, with researchers finding an arrow flint buried in his chest. Otzi’s is the oldest unsolved murder case in history, and him and his artifacts are on display in a special cold container at the South Tyrol Museum of Archaeology in Bolzano, Italy.

Since then, dedicated research centers have been established to study what the ice reveals: Norway’s Innlandet County, where a huge number of discoveries were made in 2006 after an unusually long and hot summer, has established a state-funded Glacier Archaeology Program. Among the notable discoveries are a 3k old animal hide-shoe, thought to have been worn by hunters, as well as a rare complete hunting bow from 3.3k years ago. In Canada’s Yukon territory, the expansive ice-patches are the only other site where a permanent glacial archaeology program is underway, with the Yukon Ice Patches being nominated as a UNESCO World Heritage site for their ongoing contribution to our knowledge of human history.

The study of these fossils can give us insight into how human society was organized: Burials of the Pazyryk people in Mongolia’s Altai mountains show that the horse riding nomads engaged in wide-ranging trade, with Chinese silk among the items found with the fossils. More morbidly, preserved remains of a woman and two children found on a mountaintop in the Andes suggest they had been killed as part of a human sacrifice made to the emperor known as Capacocha.

And the preservative qualities of ice have given us access to more than just human fossils: An exceptionally preserved puppy from a previously unknown species of dog/wolf dubbed Dogor — now believed to be an ancestor of both — was found in 2018 in Siberia, while the discovery of a nearly perfectly preserved baby wooly mammoth dating from 40k years ago in 2007 from the same region followed the consistent discovery of mammoth tusks that emerge from the permafrost every winter season. Scientists are working on combining mammoth DNA from these discoveries with modern elephants to genetically engineer a real life wooly mammoth in order to revitalize steppe ecosystems in Siberia, as we’ve previously written.

Despite the abundance of findings, scientists can’t afford to proceed at a glacial (pun intended) pace: Oceanfront erosion in places like Alaska means a wealth of preserved fossils are being washed into the sea, and with them our hopes of finding out more about ancient human and animal life. And the rapid progression of global warming means countless findings could be rotting in the ground before they are discovered. But as climate change appears to be here to stay, chances are the field is only going to grow, and scientists will have many chances yet to take a closer look at these frozen bits of history.