His analysis of rainfall patterns in the area suggests that rainfall in agriculture's upper-Mesopotamian heartland would, at this time, have fallen below the level needed to sustain farming reliably.

ECONOMIST: Climate change and civilisation

"We have always seen a great deal of variability in UK extreme rainfall because our weather patterns are constantly changing, but this analysis suggests we are seeing a shift in our rainfall behaviour, " she said.

BBC: Extreme rainfall in UK 'increasing'