Earth's climate could be disrupted by a huge volcanic eruption in Iceland, according to a BBC report.

Were it to erupt, Katla, which boasts a 6.2-mile crater, could pump enough ash and sulphuric acid into the atmosphere to cool the planet's climate, while the melting of “billions of gallons” of frozen glacier water would cause catastrophic flooding in Iceland.

"There has been a great deal of seismic activity," National Geographic's Ford Cochran told the BBC.

"There have been more than 500 tremors in and around the caldera of Katla just in the last month, which suggests the motion of magma. And that certainly suggests an eruption may be imminent," he added.

Katla erupts every 40 to 80 years, meaning it is now “overdue”, while a seismic disturbance recorded on July 9 has some experts predicting that a full eruption is imminent.

"The July 9 event seems to mark the beginning of a new period of unrest for Katla, the fourth we know in the last half century," said Professor Pall Einarsson.

The fallout from Katla could dwarf the Eyjafjallajokull eruption of 2010, which brought air traffic across Europe to a halt.

In 1783, the Laki crater fissures, which run through the south of Iceland and include Katla, erupted for eight months, causing a "nuclear winter” that changed earth's temperature.

"One certainly hopes that Katla's eruption will not be anything like that!" said Cochran.