Climate key to Sphinx's riddle JEREMY WATSON GLOBAL warming is one of the greatest threats to present day civilisation but work by a team of Scots scientists suggests the ancient Egyptians may have been earlier victims of climate change. The pharaohs ruled their empire for hundreds of years, spreading culture, architecture and the arts before it collapsed into economic ruin. Why that happened is one of the great mysteries of history. Now a team of scientists from Scotland and Wales believe the answer lies beneath the waters of Lake Tana, high in the Ethiopian Highlands, and the source of the...