Historic sulfur emissions—the likely cause of damage to Murujuga rock art

In July 2025, Murujuga Cultural Landscape was added to the UNESCO World Heritage List due to its outstanding cultural and spiritual significance. This brings renewed attention to Murujuga, which resides alongside industrial complexes that process commodities like liquefied natural gas (LNG). The Murujuga Rock Art Monitoring Program (MRAMP) released its third annual peer-reviewed report, aiming to understand how to protect the rock art.

This research found that there is a significant pattern of porosity in the rock surfaces near industrial areas, suggesting they are at a greater risk of fading or flaking. Previous monitoring had linked nitrogen dioxide as a potential cause, but the latest data indicates historic levels of sulfur dioxide, from industrial sites and shipping, as the most relevant factor.

This is significant because sulfur dioxide emissions have decreased sharply since the 1980s. The process where sulfur dioxide reacts to form sulfuric acid can dissolve the manganese and iron oxide minerals in the rock, leading to porosity. Our findings suggest that it was the historic peaks in sulfur dioxide, rather than current emissions, that made the rocks more porous.

Current evidence does not support industrial ammonia emissions as the primary cause of the long-term porosity pattern. It's important to note that while we have not observed acid rain or measurable acceleration of rock deterioration linked to current pollution, this does not rule out the possibility of small effects. Our research, based on three years of continuous monitoring, indicates that the elevated rock porosity is most consistent with historic sulfur dioxide emissions.