Climatologist says global warming could be behind Italian shipwreck

Global warming may have contributed to the freak storm that sank a luxury British-flagged yacht off the coast of Sicily on Monday, Italian climatologist Luca Mercalli told Reuters.

One man died and six people were missing, including British tech entrepreneur Mike Lynch, after the "Bayesian", a 56-metre-long (184-ft) sailboat, was suddenly hit by ferocious weather.

Mercalli, president of the Italian meteorological society, said the episode could have been a water spout, essentially a tornado over water, or else a downburst, a more frequent phenomenon that doesn't involve the rotation of the air.

"We don't know which it was because it all happened in the dark in the early hours of the morning, so we have no photographs," he said.

In Italy, water spouts can involve winds of up to 200 kilometres (124 miles) per hour, while downbursts can produce gusts of more than 250 km per hour.

Statistics show that downbursts are becoming more frequent around the country, which Mercalli said may be connected to global warming.

Storms and heavy rainfall have swept down Italy in recent days after weeks of scorching heat.

"The sea surface temperature around Sicily was around 30 degrees Celsius (86 Fahrenheit), which is almost 3 degrees more than normal. This creates an enormous source of energy that contributes to these storms," Mercalli said.

"So we can't say that this is all due to climate change, but we can say that it has an amplifying effect."

A similar freak storm killed four people, when their tourist boat sank on Lake Maggiore in northern Italy in May last year.

The country's varied geology makes it prone to floods and landslides, while the fact it is flanked by rapidly warming seas means it is vulnerable to increasingly powerful storms.

"Climate-driven catastrophes in Italy will become more frequent and more intense," Mercalli said.