lunes, 6 de julio de 2015

Largest freshwater lake on Earth was reduced to desert dunes in just a few hundred years


Fossilized fish. The drying of Lake Mega-Chad reveals a story of dramatic climate change in the southern Sahara, with a rapid change from a giant lake to desert dunes and dust, due to changes in rainfall from the West African Monsoon. Credit: Image courtesy of University of Royal Holloway London

Researchers from Royal Holloway, Birkbeck and Kings College, University of London used satellite images to map abandoned shore lines around Palaeolake Mega-Chad, and analysed sediments to calculate the age of these shore lines, producing a lake level history spanning the last 15,000 years.

At its peak around 6,000 years ago, Palaeolake Mega-Chad was the largest freshwater lake on Earth, with an area of 360,000 km2. Now today's Lake Chad is reduced to a fraction of that size, at only 355 km2. The drying of Lake Mega-Chad reveals a story of dramatic climate change in the southern Sahara, with a rapid change from a giant lake to desert dunes and dust, due to changes in rainfall from the West African Monsoon. The research, published in the journal Proceedings of the National Academy of Sciences confirms earlier suggestions that the climate change was abrupt, with the southern Sahara drying in just a few hundred years. [...] sciencedaily.com