Why did the Mayans disappear?

New evidence suggests that a 200 year dry spell punctuated by three severe droughts did the trick in the 8th century A.D.

And to think that all this time I thought it was global warming. Tsk, tsk.

To investigate the Mayan decline, scientists studied the ancient build-up of sediment on the sea floor just off the northern coast of Venezuela.

They discovered layers of deposits in bands of alternating dark and light colours each about a millimetre deep. The light bands consisted of algae and tiny fossils, while the dark bands were due to sediments of the metal titanium.

The scientists say titanium was washed into the sea by rivers during the rainy seasons. Shallower dark bands, which indicate lower levels of the metal, show the rivers were flowing more weakly. The researchers say this was because there was less rain.

They have worked out that in the 9th and 10th Centuries, probably just before the Mayan civilisation collapsed, there was a long period of dry weather and three intense droughts.