Undersea Volcanoes released stupendous amounts of greenhouse gases 55 million years ago, causing a cataclysmic change in the world's climate.

Scientists warn that the dramatic climate change which happened during that period could be a model for a similar disaster in the coming centuries as a result of man-made global warming.

The earth 55 million years ago was already a warmer place than it is now when it suddenly became much warmer - by between 5C and 10C - for unknown reasons.

Henrik Svensen and collea-gues from University of Oslo believe they have found the cause of the sudden release of the gases. In a study published in the journal Nature, they identified thousands of volcanic vents under the Atlantic Ocean which they believe erupted, releasing 1,500 billion tons of carbon in an instant and triggering one of the hottest periods in the history of life on Earth.

Vast quantities of methane are still trapped under the sea in the form of a semi-solid gas hydrates. Although they represent an untapped reservoir of potential energy, they are highly unstable and sudden melting could trigger a greenhouse effect.