Some of the oldest works of art in human history are falling apart, scientists say. And climate change could accelerate its decline.
New research reports that ancient rock art in Indonesian caves diminishes over time as boulders slowly peel off the walls. It’s a huge loss to human history – some of these paintings, depicting everything from animals to human figures to abstract symbols, date from around 40,000 years ago.
Salt crystals that build up on the walls are a significant part of the problem, according to the study. These salt deposits seep into the cave walls and then expand and contract as temperatures rise and fall. This process causes the rock to slowly dissolve.
Changes in weather could aid the process, scientists say.
Salt crystals can expand more easily when subjected to repeated shifts between wet, humid conditions and periods of prolonged drought. Indonesia is already a dynamic region, divided between the rainy monsoon season and the annual dry season. However, these types of shifts are expected to become more dramatic as the climate continues to warm.
In particular, according to the researchers, climate change could lead to more intense El Niño events in the future. These events can exacerbate the conditions that contribute to the formation of the harmful salt crystals.
Scientists are still debating the exact impact of climate change on El Niño, a natural climate cycle that causes changing patterns of warming and cooling in the Pacific. However, some studies suggest that events in El Niño could be more serious in the future.
The new study, led by Jillian Huntley at Griffith University, Australia, examined 11 ancient cave art sites in South Sulawesi, Indonesia. The researchers found evidence of salt formation at all 11 locations. In three places, they found the types of crystals known to cause stones to break apart.
It’s a small sample; There are more than 300 known cave art sites in the region. However, research suggests that salt crystals may actually be part of the problem.
In recent years, archaeologists have reported that the art appears to be deteriorating rapidly – in some places, experts have reported that up to an inch of art has disappeared every few months.
Scientists have suggested several theories as to what could be causing it. Coupled with climate change, they have suggested that pollution and other disruptions from nearby limestone mining could affect the fragile paintings.
It’s probably all, suggest Huntley and her colleagues. However, they add that climate change is a growing threat that deserves more attention.
In fact, they argue, along with mining, salt mining is “the most pressing threat to the preservation of rock art in this region”.
Reprinted from E&E News with permission from POLITICO, LLC. Copyright 2021. E&E News provides important news for energy and environmental professionals.