Is climate change eroding European monuments?

ROME — For centuries, Europe's monuments have withstood earthquakes, fire and plundering. Now cultural treasures from the Colosseum to Westminster Abbey could face new threats from climate change, a study says.

Increased rains in northern Europe could wash away layer after layer of ancient stone, while rising heat in southern and central Europe could cause age-old monuments to crack and disintegrate, according to the European Union-funded study.

Experts have long warned that a rise in sea levels attributed to global warming threatens low-lying areas, including treasures like Venice or sites in flood-prone regions.

But the three-year study didn't look only at the catastrophic impact of storm surges, landslides and floods. It also took into account the slow erosion that Europe's cultural heritage could suffer from climate change, said Cristina Sabbioni, the study's coordinator.

"We needed to put this problem on the table, because so far it has been politically ignored," said Sabbioni, a physicist with Italy's National Research Council.

Climatologists, chemists, geologists and biologists used projected climate data to predict how marble, limestone, wood and other materials commonly used in ancient buildings would fare in future weather patterns until 2099, Sabbioni said.

Researchers produced a "Vulnerability Atlas" of Europe, with maps that indicate which areas will suffer an increase or decrease in risk factors, from damage caused by salt crystals to corrosion of medieval stained-glass windows.

According to the study, lower humidity during the summer in Britain, France, northern Spain and central Europe will increase the amount of salt deposited on monuments.

This is especially dangerous for the region's Gothic cathedrals, whose elaborate carvings are made of soft porous stone that absorbs sea salt from the air. Once the water evaporates, the salt crystallizes and puts pressure on the surrounding stone, Sabbioni said.

"If the salt is deposited on the surface, the damage is aesthetic, and this is a dramatic problem for frescoes," she said. "But if it is absorbed we have internal breakup of the material."

Less rain in southern Europe will force authorities to spend more money to clean monuments blackened by pollution, while an expected rise of precipitation in northern Europe could wash away an increasing amount of ancient stone each year.

Monuments built of marble and limestone, such as the Colosseum in Rome and the Parthenon in Athens, will also suffer due to increased temperature fluctuations that cause such materials to expand and contract, causing fractures and breakage. Central Europe, southern Spain and Greece will be the areas most affected due to the drier climate and rising temperatures, the study says.