How climate change helps and hinders archaeology

Climate change is rarely associated with anything positive. Archaeology is one field, however, that does seem to be benefiting as glaciers rapidly melt, permafrost retreats even further and rivers or lakes dry up.

Recent years have seen a string of archaeological discoveries of objects previously frozen in ice – and thus shielded for centuries from curious gazes, destruction or plunder.

While many finds are being exposed by the melting ice, the rising air and water temperatures seen in past decades are also dramatically impacting the field. Objects in cold, wet climates that were protected for millennia are in danger of disappearing thanks to climate change.

Treasures from the ice

The unfortunately no longer eternal ice has preserved sensational finds such as "Ötzi the Ice Man," discovered in 1991, for posterity. Thanks to Ötzi's excellent state of preservation, researchers got deep insight into how he and others lived in the Alps between Italy and Austria around 5,300 years ago.

More and more often, high-altitude archaeologists are finding impressive evidence of past tragedies. Only recently, researchers from Peru and Poland presented a facial reconstruction of an Inca mummy named "Juanita", an approximately 14-year-old girl who was sacrificed to the gods more than 500 years ago. In a bloody ritual named Copachoca, the Inca sought divine protection against natural disasters.

"Juanita" was found as a frozen bundle in 1995 at an altitude of more than 6,000 meters (19,685 feet) on the Ampato Volcano in southern Peru. Due to melting ice and erosion, the body had fallen from a higher Inca site into the volcanic crater.

Frozen time capsules

In the Alps and in Scandinavia, people are more frequently finding weapons, sleighs and garments from Roman or Medieval times. Researchers can learn a lot about the lives of our forebears thanks to the good state of conservation.

Many finds are turning up where permafrost is shrinking most rapidly. In the Antarctic, radar pictures reveal ancient river landscapes under the ice. In Alaska, thousands of old settlements are now being exposed. In Siberia, researchers uncovered the remains of mummies thought to be more than 3 million years old. In Canada, even a perfectly preserved mummified baby mammoth has been discovered.

Race against time

These are fortuitous finds, but the clock is running. In places where permafrost is conserving organic matter in exceptional state today, colored streaks on the ground may be all that is left in within a few years.

Melting glaciers, heavy rainfall and rising sea levels all present new challenges for archaeology. On the Mediterranean, many ancient port cities are under threat.

Droughts expose sunken treasures

Climate change isn't just responsible for melting ice and flooding. It also causes devastating drought. And what for archaeologists is partly a good thing is actually a disaster for eco-systems and inhabitants of affected zones. Fish are dying off on masse, fields become impossible to cultivate and drinking water is in short supply.

In Iraq, for example, a 3,400-year-old city suddenly emerged from a reservoir due to extreme drought. German and Kurdish archaeologists were able to briefly examine the Bronze Age city before the erstwhile center of power of the Mittani empire was submerged again.

In the western Spanish city Caceres, the Dolmen of Guadalperal – known as the Spanish Stonehenge – suddenly became visible in a reservoir due to drought. The megalithic monument was built from more than 150 standing stone blocks about 7,000 years ago.

Shipwrecks have been exposed in the dried-out US Mississippi River and beyond. In Europe, the Danube River saw record lows, exposing German World War II warships in Serbia. The numerous wrecks are not only a danger to shipping, they also often contain ammunition, perilous for more than just the environment.

Massive problem with unexpected perks

The double-edged nature of the situation can be seen in Brazil. Massive drought in the Amazonian region has exposed ancient, somewhat frightening face carvings on several rocks in the city of Manaus.

The prehistoric carvings depict a variety of facial expressions, from smiles to eerie looks, and are vaguely reminiscent of our present-day emojis. Presumably, Indigenous people living in this area in pre-Columbian times made the engravings about 2,000 years ago.

The etchings are an "invaluable" find in terms of understanding these people, Beatriz Carneiro, a historian and member of Brazil's National Historic and Artistic Heritage Institute said. "Unfortunately they are showing up again because of the drought," Carneiro told French news agency AFP.

Huge drought is causing massive problems for many of the rivers in the Amazon. The level of the Rio Negro, where the engravings were discovered, dropped significantly over the summer. Last week the river recorded its lowest flow in 121 years. According to the archaeologists there, this is a conservation risk, though above everything the dryness is depriving locals of their livelihoods.