Researchers from the University of Bristol (UK) reported the discovery of the causes of rapid sea level rise during the two episodes that occurred about 14 600 8 200 years ago.

Responsibility is assigned to a process called "destruction saddles" (saddle-collapse.

After modeling of climate and ice cover those distant times, Lauren Gregoire and his colleagues came to the conclusion that the chain of events led to the collapse of the ice sheet that covered North America, in several parts. As a result, the melting has accelerated and became ice-free corridor.

Ice dome in the thickness to 3 km occur in areas with abundant snowfalls and high relief - for example, in the Rocky mountains. Together with saddles, i.e. ice valleys between the domes, they form ice sheets.

When the ice ages came to an end, ice, of course, was melting from below upward. Sooner or later he traveled to these saddles, they started to sink and fall to warmer elevations, where melt even stronger. As a result of all 500 years saddle disappeared, and domes have remained.

Meltwater led to a rapid rise in sea levels: in the first case - by 9 m 500 years, in the second - 2.5 m for the same period. The model showed that up to half of the increase comes from the melting of saddles, while the rest is given gradually thawing ice sheets Europe and Antarctica.

The study is published in the journal Nature.

Prepared from Bristol University.